Suppressing solvent adducts via coordination competition enables scalable perovskite photovoltaics

Domain: physics
Published: 2026-01-16
Editorial outcome: minor_revision

Abstract
Scalable coating methods are indispensable for the commercialization of perovskite photovoltaics. However, fundamental divergences in crystallization dynamics hinder the direct adaptation of spin-coating optimization strategies. Furthermore, the limited understanding of crystallization control under scalable conditions constrain the fabrication of high-quality perovskite films. Herein, we identify the solvent-precursor interaction time (τint) as the critical, yet previously overlooked, kinetic parameter governing film quality in scalable processes. We demonstrate the prolonged τint inherent to blade coating stabilizes solvent-adduct phases, increases solvent retention, and ultimately degrades film crystallinity. To resolve this, we introduce a dynamic coordination competition strategy that modulates the precursor coordination equilibrium, thereby effectively shortening τint and yielding high-crystallinity films with enhanced phase purity. Consequently, the blade-coated devices deliver power conversion efficiencies (PCEs) of 26.5% (0.0665 cm2) and 22.9% (728.0 cm2). Our findings provide a kinetic knob for crystallization control and establish a robust protocol for large-area manufacturing of high-quality perovskite films.

Introduction
The scalable fabrication of high-efficiency perovskite photovoltaics represents a critical step toward commercial viability1,2. Currently, the majority of high-efficiency perovskite solar cells (PSCs) have been achieved predominantly through spin coating3,4. This is largely attributed to pioneering advancements in precursor chemistry5–7, antisolvent quenching8,9, and interface engineering10–12. These innovations together facilitate the controlled growth of high-quality perovskite films.

However, the crystallization kinetics of perovskite film formation differ fundamentally between spin coating and scalable coating processes. In spin coating process, wet-film formation is dominated by centrifugal thinning and antisolvent, which enables precise control over nucleation and crystal growth. By contrast, scalable coating techniques depend on capillary flow and natural solvent evaporation13,14. This inherent dichotomy in fluid dynamics and film formation methods translates into distinct crystallization processes, which ultimately affect the optoelectronic properties of perovskite films. Consequently, crystallization control strategies that succeed for spin-coating systems cannot be directly applied to scalable processes. In turn, the performance of PSCs fabricated via scalable coating has not yet reached the level of aspiration required for commercial deployment. Crucially, our understanding of perovskite film crystallization under scalable deposition conditions remains relatively limited. While the overarching differences in fluid dynamics are appreciated, the fundamental kinetic parameter that dictates final film quality has remained elusive.

Here, we identify the solvent-precursor interaction time (τint) in the wet film as the missing link. During blade coating, the slow solvent evaporation rate prolongs τint, stabilizing the lead halide•N-methyl-2-pyrrolidone (NMP) adduct, locking in solvent residue, and ultimately compromising film crystallinity. To overcome this bottleneck, we devise a dynamic coordination competition strategy, employing the hydroxyl-terminated molecular bis (2-hydroxyethyl) dimethylammonium chloride (2OH) that outcompetes NMP for Pb2+ coordination. This modulation intervention effectively displaces the adduct equilibrium, markedly shortening τint. This tailored approach suppresses adducts formation and reduces NMP residue, enabling the formation of high-crystallinity perovskite films with enhanced phase purity and reduced defect density. Consequently, our blade-coated devices achieve power conversion efficiencies (PCEs) of 26.5% (0.0665 cm2), 22.9% (20.8 cm2), and 22.9% (728.0 cm2, certified at 22.58%), together with excellent long-term operational stability.

Results
The comparison of perovskite films prepared by spin-coating and blade coating
To evaluate crystallinity differences, we benchmarked blade-coating films against spin-coating references prepared using identical precursor formulations and annealing conditions (see experimental details in Methods). X-ray diffraction (XRD) analysis reveals that the spin-coating films exhibit significantly higher diffraction intensities than their blade-coating counterparts (Fig. 1a).

To investigate the reasons behind the considerable crystallinity differences under various processing conditions, we conducted XRD analysis of the intermediate phase films (Fig. 1b). The scattering peak at 2θ=8.26° corresponds to the PbI2-NMP solvent phase15,16. In intermediate wet films (following anti-solvent dripping or gas quenching but prior to annealing), the intensity of the PbI2-NMP in the blade-coated films was markedly higher than that in the spin-coated ones, which suggests that the intensity of the solvent intermediate phase in the wet film is critical to the final film quality. Subsequently, we measured the NMP content in the intermediate phase wet films prepared by different methods using Liquid Chromatography-Mass Spectrometry (LC-MS, Fig. 1c, Supplementary Fig. 1). This quantification relies on a linear calibration establishing the correlation between integrated signal intensity and NMP concentration (Supplementary Fig. 2a). Cross-sectional SEM imaging of the annealed perovskite films reveals thicknesses of ~592 nm and ~703 nm for spin-coating and blade-coating films, respectively (Supplementary Fig. 2b). Utilization of a standardized extraction protocol ensures that these thickness discrepancies do not bias the LC-MS solvent residue analysis (see the LC-MS in Methods and Supplementary Fig. 2c). Quantitative LC–MS analysis reveals that blade-coated films retain substantially higher NMP concentrations than their spin-coated counterparts processed from the identical precursor (Supplementary Fig. 2d). This difference may arise from the prolonged solvent-precursor interaction time in blade-coating.

The solvent-precursor interaction time and solvent residue in the wet films for different processing methods are illustrated in Fig. 1d. To weaken the solvent-precursor interaction in the blade-coating process, we introduced bis(2-hydroxyethyl) dimethylammonium chloride (named 2OH) molecules into the perovskite precursor. XRD analysis was performed on annealed perovskite films prepared by blade-coating with and without 2OH molecules (Fig. 1e). The results show that the 2OH-treated perovskite films exhibited stronger crystallinity, indicating improved crystallization quality. Subsequently, we conducted XRD analysis on the intermediate phase films (Fig. 1f). The control group displayed an unfavorable PbI2-NMP solvent phase, while the 2OH-treated wet films showed a suppressed solvent phase. This suggests that the 2OH additive effectively suppresses the interaction between PbI2 and NMP, thereby reducing NMP residues in the intermediate phase, which in turn promotes better film crystallinity (Fig. 1g, Supplementary Fig. 2e). DFT calculations were performed to analyze the binding energy of the interactions between 2OH, PbI2, and NMP (Supplementary Table S1). The binding energy between 2OH and PbI2 (−2.118 eV) is significantly higher than that between PbI2 and NMP (−1.116 eV), indicating that PbI2 prefers to bind with 2OH molecules rather than NMP.

Notably, a coherent evidentiary chain validates τint as the governing variable. Prolonged solvent residence during spin-coating proves intrinsically detrimental (Supplementary Fig. 3), while gas-quenched spin-coating reproduces kinetic bottlenecks that are specifically resolved by the additive (Supplementary Fig. 4). Moreover, the catastrophic nucleation induced by antisolvent baths confirms that abrupt physical extraction is incompatible with scalable thick films (Supplementary Figs. 5–6, Supplementary Video 1–2). This establishes coordination competition as the essential resolution for kinetic regulation.

Mechanistic origin of the suppressed solvent residue in wet films
We analyzed the transition from the precursor solution to the intermediate phase wet film during the blade-coating process using In-situ Grazing Incidence X-ray Diffraction (In-situ GIXRD) measurements (Fig. 2a). In the control group (blade-coated films without any additives), a distinct PbI2-NMP solvent peak appeared in the intermediate phase (Supplementary Fig. 7). In contrast, the 2OH-treated group did not exhibit PbI2-NMP solvent peak at the initial stage, showing only an amorphous solvent phase. This suggests that the introduction of 2OH effectively weakens the interaction between PbI2 and NMP.

To further investigate how the additive alters solvent-precursor interactions, we performed Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. Upon mixing 2OH with PbI2, the stretching vibration peak of the OH functional group (3278 cm−1) shifted to a higher wavenumber of 3398 cm−1, indicating strong coordination between the OH group and Pb2+ (Fig. 2b). In addition, mixing 2OH with FAI induces discernible shifts in both the C=N stretching vibration of FAI and the O–H stretching vibration of 2OH, indicating an interaction between the two species (Fig. 2c). The C=O stretch in pure NMP at 1692 cm−1 shifted to 1625 cm−1 upon the addition of PbI2, whereas it shifted to 1637 cm−1 in the 2OH-PbI2-NMP complexes. A free NMP peak appeared at 1688 cm−1 (Fig. 2d). These observations further confirm that 2OH competes with NMP for PbI2 coordination and thereby weakens the PbI–NMP interaction. Tracking ʋC=O evolution across PbI2:2OH ratios (500:1–5:1) reveals a concentration-dependent coordination shift (Supplementary Fig. 8 and Table S1). The additive competitively displaces NMP, progressively weakening the Pb···O=C interaction to restore the free solvent population. Notably, a distinct feature emerges at 1613 cm−1 in the high-concentration regime, attributable to robust hydrogen bonding (Pb-O-H···O=C) driven by the polarization-enhanced acidity of the coordinated hydroxyl group.

To further elucidate how 2OH attenuates the coordination between PbI2 and NMP, we collected Pb LIII-edge absorption spectra using extended X-ray absorption fine spectroscopy (EXAFS) (Fig. 2e). The peak in the R-space at approximately 2.2 Å corresponds to the Pb…O bond in the PbI2-NMP17,18, which shifts to 2.45 Å in the PbI2-2OH-NMP complex, indicating an elongated Pb–O distance and confirming that 2OH effectively weakens the interaction between PbI2 and NMP.

Building on this, we performed XRD measurements to further investigate the interactions between 2OH, FAI, and PbI2 (Fig. 2f). The peak of pure PbI2 at 12.78° corresponds to its (001) reflection. After adding 2OH, the PbI2 peak vanishes, and a new diffraction peak appeared at 9.97°, which is attributed to the diffraction peak of the one-dimensional perovskite structure of PbI2-2OH. The peak of FAI at 25.56° corresponds to its (040) reflection19. The intensity of this peak increases in the presence of 2OH, suggesting that 2OH enhances the crystallinity of FAI, which may play a role in the subsequent oriented growth of the perovskite film.

To demonstrate that the OH functional group serves as a tool for 2OH to compete with NMP for coordination with PbI2, we designed molecules without OH groups (Tetramethylammonium chloride, 0OH) and molecules with reduced OH number (Choline chloride, 1OH). The chemical structures of these three molecules are illustrated in Supplementary Fig. 9. To investigate the influence of additives with varying numbers of OH groups on the interaction between the solvent and the precursor, we monitored the precursor solution to the intermediate phase transition using in-situ GIXRD (Fig. 3a). In the control group, the PbI2-NMP solvent phase emerged at 32 s, while in the 0OH group, it appeared slightly earlier (30 s). By contrast, the PbI2-NMP peak was progressively delayed in the 1OH groups, and was not detected within the observation window for the 2OH group. These results indicate that OH-terminated molecules effectively compete with NMP for PbI2 coordination, and that the coordination ability strengthens as the number of OH groups increases.

To compare the strength of interactions between molecules with varying numbers of OH groups and the solute/solvent, as well as their impact on the PbI2-NMP interaction, we conducted FTIR measurements. For the neat additives, the C-N stretching vibration of 0OH is located at 950 cm−1, while the O-H stretching vibrations of 1OH and 2OH appear at 3149 cm−1 and 3170 cm−1, respectively. Upon coordination with PbI2, these peaks shift to 947 cm−1, 3250 cm−1, and 3499 cm−1, respectively, indicating a progressive enhancement in coordination ability with PbI2 as the number of OH groups increases (Fig. 3b). A similar trend is observed with FAI. The C=N stretching vibration of FAI in 0OH, 1OH, and 2OH shifted from 1699 cm−1 to 1701 cm−1, 1705 cm−1, and 1710 cm−1, respectively, while the N–H stretching vibration shifted from 3455 cm−1 to 3456 cm−1, 3462 cm−1, and 3465 cm−1, respectively. These systematic shifts further demonstrate that, with the increasing number of OH groups, the coordination ability with both PbI2 and FAI is also enhanced (Fig. 3c).

Furthermore, the C=O stretching vibration peak of PbI2-NMP at 1625 cm−1 shifts to 1626 cm−1 (PbI2-0OH-NMP), 1633 cm−1 (PbI2-1OH-NMP), and 1636 cm−1 (PbI2-2OH-NMP) upon the introduction of additives with varying numbers of OH groups (Fig. 3d). These shifts indicate that, as the number of OH groups increases, the stronger additive–PbI2 coordination progressively weakens the PbI2–NMP interaction. The full FTIR spectra of ternary PbI2-xOH-NMP are shown in Supplementary Fig. 10a–c. This conclusion is further corroborated by the EXAFS spectra. The Pb-O atomic distances at the Pb LIII-edge for PbI2-NMP, 0OH-PbI2-NMP, 1OH-PbI2-NMP, and 2OH-PbI2-NMP (Supplementary Fig. 11) are 2.18 Å, 2.19 Å, 2.32 Å, and 2.42 Å, respectively. These results indicate that, as the number of OH groups increases, the Pb-O bond length gradually elongates, thereby weakening the interaction between PbI2 and NMP. The density functional theory (DFT) calculations optimized structures of various molecular systems and their corresponding binding energies, as shown in Supplementary Fig. 12 and Supplementary Table 2, further support this conclusion.

Additionally, X‑ray photoelectron spectroscopy (XPS) corroborates the enhanced coordination imparted by the OH functional groups. The Pb 4f binding energy shifts to higher binding energies as the number of OH groups increases, further supporting the notion of stronger coordination between the OH groups and PbI2 (Fig. 3e). Moreover, the XPS spectra of I 3d and N 1s (Supplementary Fig. 13a–b) reveal enhanced coordination with FAI as the number of OH groups increases. Taken together, these results provide compelling evidence that the introduction of OH-containing molecules outcompetes NMP for coordination with PbI2, thereby weakening the interaction between PbI2 and NMP.

To further elucidate the interactions between molecules with varying numbers of OH groups, PbI2, and FAI, we performed XRD analysis. Upon mixing PbI2 with 0OH, peaks appeared at 12.75° and 10.56°, assigned to the (001) plane of PbI2 and the one-dimensional structure of PbI2-0OH, respectively (Fig. 3f). When mixed with 1OH/2OH, peaks appeared at 9.56° and 9.45°, characteristic of the corresponding one-dimensional structures of PbI2-1OH/2OH phases20. Additionally, the original PbI2 peak disappears, indicating that the presence of OH-containing molecules strengthens the interaction with PbI2. When FAI is mixed with 1OH or 2OH, the intensity of the FAI (040) reflection increases, indicating that OH-containing molecules enhance the crystallinity of FAI. Interestingly, in the FAPbI3-xOH complexes, FAPbI3-0OH exhibited a weak peak at 10.56° (PbI2-0OH one-dimensional perovskite peak), while a pronounced peak at 11.9° corresponded to δ-FAPbI3 (Supplementary Fig. 14a)21. By contrast, the peaks at 6.47° and 6.65° identify the one-dimensional PbI2-1OH and PbI2-2OH phases, respectively. Notably, the δ-FAPbI3 peak at 11.9° significantly decreased (Supplementary Fig. 14b–c). These results suggest that OH-containing molecules preferentially interact with PbI2, forming complexes that delay the reaction between FAI and PbI2. FTIR further confirms the interactions between xOH and FAI/PbI2. For the 0OH molecule, it shows negligible interaction with either PbI2 or FAI (Supplementary Fig. 15a), whereas 1OH and 2OH molecules exhibit interactions with both species (Supplementary Fig. 15b–c). These observations provide additional evidence for the role of OH-containing molecules in preferentially forming intermediate complexes that delay the reaction between FAI and PbI2, thus influencing the crystallization process.

LC-MS analysis of the intermediate phase wet films after gas quenching (Supplementary Fig. 16) indicated that the residual NMP content falls steadily as the number of introduced OH groups increases. This suggests that the introduction of OH-containing molecules weakens the interaction between PbI2 and the solvent, thereby reducing solvent residue and setting the stage for higher-quality perovskite film formation.

To confirm how this modulation strategy translates into the perovskite film quality, we conducted spatially resolved photoluminescence mapping (PL mapping) tests (Fig. 3g). Consistent with the LC-MS results, the PL intensity becomes progressively higher as the number of OH groups increases, signaling the reduced non-radiative recombination and improved crystallinity of the perovskite films, which also correlates with the weaker interaction between PbI2 and NMP. Subsequently, we performed in-situ GIXRD measurements to monitor the perovskite crystallization process (Supplementary Fig. 17a–d). The peaks at 11.9° and 14.2° correspond to the δ phase and α-phase of FAPbI322, respectively. The evolution of the α and δ phases of perovskite films with different OH additives over time is shown in Supplementary Fig. 17e. Compared to the others samples, the δ-FAPbI3 phase in the 0OH sample decays most slowly, with its conversion to α-FAPbI3 proceeding at the slowest rate and exhibiting the weakest diffraction peak intensity. As the number of OH groups increased, the conversion rate to α-FAPbI3 accelerated and amplified the intensity of α phase. This suggests that the progressively weakened solvent-solute interaction promotes more efficient conversion to the α-FAPbI3 phase and higher film crystallinity.

Device performance and stability
We fabricated devices with an ITO/NiOx/2-(pyren-1-yl)ethyl) phosphonic acid (Py3)/Cs0.02FA0.98PbI3/LiF/C60/BCP/Ag structure using the blade-coating configuration detailed in Supplementary Fig. 18 and Supplementary Video 3, and assessed their performance using additives with varying numbers of OH groups. Relative to the control one, the devices with 0OH molecules exhibited a slight decrease in performance, whereas those with 1OH/2OH additives showed significant improvements, primarily due to enhanced fill factor (FF) and open-circuit voltage (VOC) (Supplementary Fig. 19, Table S3). We also optimized the concentration of 2OH molecules, with the optimal concentration determined to be 0.3% mol (Supplementary Fig. 20, Table S4). As shown in Fig. 4a, the J-V curves show that the highest PCE for the control device is 25.3% (VOC=1.15 V, JSC=26.2 mA/cm², FF=84.0%), while the 2OH device achieves a PCE of 26.5% (VOC=1.18 V, JSC=26.3 mA/cm², FF=85.5%). The stabilized PCE for the control and 2OH devices is 25.2% and 26.2%, respectively (Fig. 4b). The integrated current density (JSC) values derived from the EQE spectra were 25.1 mA/cm2 for the control and 25.4 mA/cm2 for the 2OH treated PSCs, which match well with the J-V measurement (Supplementary Fig. 21). Figure 4c presents the statistical comparison of PCE for 15 devices under each condition, further highlighting the significant improvements in both FF and VOC upon the addition of the 2OH (Supplementary Fig. 22). Extending the strategy to triple-cation and mixed-halide compositions (Supplementary Figs. 23, 24), alongside alternative 2-pyrrolidone solvent systems (Supplementary Fig. 25), yields consistent performance enhancements that validate its broad applicability.

To evaluate the scalability, we fabricated perovskite mini-modules with an active area of 20.8 cm² featuring precise laser-scribed interconnects with a total dead-area width of approximately 280 µm (Supplementary Fig. 26a). Electroluminescence (EL) mapping captures the contrast in macroscopic homogeneity; the unmodified blade-coated module exhibits subdued, speckled luminescence indicative of widespread non-radiative defects, whereas the 2OH-treated counterpart displays a consistently bright and uniform emission profile (Supplementary Fig. 26b). Infrared thermography (IRT) under forward bias further distinguishes the electrical integrity. Distinct localized hot spots revealing low-resistance shunt paths in the control are effectively eliminated in the modified module, which maintains a homogeneous thermal distribution (Supplementary Fig. 26c).

Furthermore, statistical analysis of ten mini-modules (20.8 cm2) substantiates scalability, where 2OH-modified devices achieve 22.6 ± 0.8% efficiency versus the 20.9 ± 1.0% for control (Supplementary Fig. 27). The champion PCE of modules was improved from 21.5% to 22.9% (Fig. 4d and Supplementary Table 5). We next translated the strategy to a pre-pilot sub-module (30 × 30 cm², an aperture area of 728.0 cm²), which yielded a PCE of 22.9% under reverse scan and 21.9% under forward scan (Fig. 4e and Supplementary Table 6). A record certified PCE of 22.58% was also achieved (Supplementary Fig. 28), demonstrating the suitability of this strategy for commercial-scale production. A statistical summary of efficiencies across scalable fabrication methods is presented in Supplementary Fig. 29 (Supplementary Tables 7, 8). Our method achieved champion PCEs of 26.5% for small-area cells, 22.9% for 20.8 cm² mini-modules, and 22.9% for 728.0 cm² sub-modules, surpassing state-of-the-art benchmarks for blade- and slot-die coating. These results reveal the efficacy of our strategy for scalable manufacturing.

To elucidate the origins of the improved VOC and FF afforded by the 2OH additive, we first conducted current-flow microscopy (CFM) characterization. CFM maps revealed an increase in surface current after 2OH treatment, suggesting a reduction in defect state density (Supplementary Fig. 30a,c)23. We further measured the surface potential of the perovskite films using Kelvin Probe Force Microscopy (KPFM). After 2OH treatment, the films exhibited a reduced surface contact potential difference, indicating an increased work function and a more p-type surface (Supplementary Fig. 30b,d)24. This result is consistent with the UPS data, which showed a better alignment of the energy levels, facilitating efficient charge transfer and improving the overall FF (Supplementary Fig. 31a–b). Furthermore, the perovskite films treated with 2OH displayed enhanced photoluminescence (PL) intensity and longer transient photoluminescence (TRPL) carrier lifetimes, indicating a reduction in defect state density and non-radiative recombination, as well as an overall improved film quality (Supplementary Fig. 31c–d)5.

The charge transfer and recombination dynamics in the PSCs were investigated using transient photocurrent (TPC) and transient photovoltage (TPV) measurements. The observed reduction in TPC photocurrent decay time and the extension of TPV decay time further confirm efficient carrier extraction and reduced recombination (Supplementary Fig. 32a–b)25. A smaller energy disorder (EU = 12.07 meV) was observed in the devices with 2OH, compared to the control devices (EU = 14.05 meV). This indicates that the introduction of 2OH effectively reduced energy disorder and mitigated the energy loss associated with the reduction of the VOC deficit (Supplementary Fig. 32c)26. Additionally, the overall saturation dark current of the devices decreased, as evidenced by the dark J-V curve, which suggests a reduction in shallow energy level defects (Supplementary Fig. 32d)3. The plot of VOC versus the logarithm of light intensity is shown in Supplementary Fig. 32e. The deviation of the slope from unity (kT/q) suggests trap-assisted recombination in the solar cells, where k is the Boltzmann constant, T is the absolute temperature, and q denotes the elementary charge. The slope for the 2OH-based device is 1.31 kT/q, significantly smaller than the slope of 1.58 kT/q for the control device. This indicates that defect-assisted charge recombination is substantially reduced27. Moreover, the lower trap density of states (tDOS) characterization revealed a lower trap density across the energy range (0.30–0.49 eV) (Supplementary Fig. 32f), which is expected to minimise non-radiative recombination and voltage deficit28.

Finally, we evaluated the stability of small-area devices under continuous 1 sun illumination while tracking the maximum power point (MPP). After 920 h, the PCE of the control devices decreased to 80% of their initial efficiency, while the 2OH devices maintained 92% (Fig. 4f). The devices at 85°C thermal stress (ISOS-D-2 protocol) was also performed. The 2OH treated devices maintained over 92% of their initial efficiency after 550 h, whereas the device based on control remained only 85% (Supplementary Fig. 33). The enhanced stability may be attributed to the reduced NMP residue and improved crystallinity in the 2OH perovskite films.

Methods
Materials
All materials used in this work were obtained commercially and used without further purification unless otherwise specified. The transparent ITO glass substrates (ITO, 10 Ω per square, transmittance 88%) were purchased from Shenzhen Huayu United Technology Co., Ltd. The perovskite raw materials including lead iodide (PbI2, purity 99.999%), cesium iodide (CsI, purity 99.999%), formamidinium iodide (FAI, purity 99.99%), methylammonium chloride (MACl, purity 99.9%), lithium fluoride (LiF, purity 99.99%) and C60 (purity 99.9%) were all purchased from Advanced Election Technology Co., Ltd. Bathocuproine (BCP, purity 99%), Piperazine Dihydriodide (PDI, purity 99.5%), Propylammonium chloride (PACl, purity 99.8%) and 1,8-Octanediamine dihydriodide (ODADI, purity 99%) were purchased from Xi’an Polymer Light Technology Corp. Inc. L-α-phosphatidylcholine (LP, purity 99%) was obtained from Shanghai Macklin Biochemical Technology Co., Ltd. The NiOx nanoparticles (~10 nm diameter) were sourced from Advanced Election Technology. We employed in-house synthesized (2-(pyren-1-yl)ethyl)phosphonic acid (Py3) as the hole selective contact material3. The required solvent including N, N-Dimethylformamide (DMF, extra dry, purity 99.8%), dimethyl sulfoxide (DMSO, anhydrous, ≥99.9%), isopropanol (IPA, extra dry, purity 99.5%), methanol (extra dry, purity 99.8%), 2-methoxyethanol (2-ME, extra dry, purity 99.9%), N-Methyl-2-pyrrolidone (NMP, extra dry, purity 99.9%), isopropanol (IPA, extra dry, purity 99.5%), 2-pyrrolidone (PDI, purity 99%) and silver (Ag, purity 99.99%) were purchased from Sigma-Aldrich Inc.

Preparation of perovskite precursors and films
For the preparation of perovskite films with a composition Cs0.02FA0.98PbI3, 1.65 M perovskite precursor solution was prepared by dissolving FAPbI3 and CsPbI3 powder in mixed solvent of 2-Me and NMP at volume ratio 10:1. Additional, 10 mol% PACl and 15 mol% MACl, 2 mg/mL LP and 0.2 mg/mL ODADI were added to the precursor solution as additives. Then, the filtered perovskite precursor was blade-coated onto the substrates with a gap of 140 μm at a coating speed of 25 mm/s under dry air quenching. The blade-coating processes were performed under ambient conditions (25±1°C) with controlled humidity (~30%). The wet perovskite films were then transferred onto a hot plate and annealed at 130°C for 5 min in air.

For the preparation of perovskite films with a composition MA0.05Cs0.02FA0.93PbI3, 1.65 M perovskite precursor solution was prepared by dissolving MAI, FAPbI3 and CsPbI3 powder in mixed solvent of 2-Me and NMP at volume ratio 10:1. Additional 10 mol% PACl and 15 mol% MACl, 2 mg/mL LP and 0.2 mg/mL ODADI were added to the precursor solution as additives. Then the filtered perovskite precursor was blade-coated onto the substrates with a gap of 140 μm at a coating speed of 25 mm/s under dry air quenching. The blade-coating processes were performed under ambient conditions with controlled humidity (~30%). The wet perovskite films were then transferred onto a hot plate and annealed at 130°C for 5 min in air.

For the preparation of perovskite films with a composition (Cs0.02FA0.98)PbI3(0.98)(MAPbBr3)0.02, 1.65 M perovskite precursor solution was prepared by dissolving FAPbI3, CsPbI3 and MAPbBr3 powder in mixed solvent of 2-Me and NMP at volume ratio 10:1. Additional 10 mol% PACl and 15 mol% MACl, 2 mg/mL LP and 0.2 mg/mL ODADI were added to the precursor solution as additives. Then the filtered perovskite precursor was blade-coated onto the substrates with a gap of 140 μm at a coating speed of 25 mm/s under dry air quenching. The blade-coating processes were performed under ambient conditions with controlled humidity (~30%). The wet perovskite films were then transferred onto a hot plate and annealed at 130°C for 5 min in air.

For the preparation of perovskite films with a composition Cs0.02FA0.98PbI3, 1.65 M perovskite precursor solution was prepared by dissolving FAPbI3 and CsPbI3 powder in mixed solvent of 2-Me and PDI at volume ratio 12:1. Additional, 10 mol% PACl and 15 mol% MACl, 2 mg/mL LP and 0.2 mg/mL ODADI were added to the precursor solution as additives. Then, the filtered perovskite precursor was blade-coated onto the substrates with a gap of 140 μm at a coating speed of 25 mm/s under dry air quenching. The blade-coating processes were performed under ambient conditions with controlled humidity (~30%). The wet perovskite films were then transferred onto a hot plate and annealed at 130°C for 5 min in air.

Fabrication of perovskite solar cells by blade-coating
The pre-patterned ITO glass substrates were cleaned by sequentially washing with detergent, deionized water, acetone, and isopropanol (IPA), followed by drying with a pure nitrogen flow. Before use, the ITO was cleaned with ultraviolet ozone for 20 min. Then the substrate was spin-coated with a thin layer of NiOx nanoparticle film (20 mg/ml NiOx water solution) at 1500 rpm for 30 s, and annealed in ambient air at 125°C for 10 min. 0.5 mg/ml Py3 in mixed solvent of methanol and DMF at a volume ratio 2:1 was deposited onto the NiOx at 3000 rpm for 40 s. Afterwards, the film was annealed at 115°C for 20 min. After cooling down to room temperature, perovskite films were coated on these layers following the above-mentioned method. For the surface passivation layer, PDI was dissolved in isopropyl alcohol (IPA) to form a saturated solution. The PDI solution was spin-coated on top of the as-prepared perovskite at 5000 rpm for 30 s, and then transferred to the hot plate and annealed at 100°C for 5 min. After cooling down to room temperature, the whole device was transferred to a vacuum chamber under a base pressure of <5.0 × 10−6 Pa. 0.6 nm LiF at a rate of 0.1 Å/s, 30 nm C60 at a rate of 0.3 Å/s and 6 nm BCP at a rate of 0.1 Å/s were thermally evaporated on the perovskite thin film sequentially (Angstrom Engineering Inc, Beijing technol science co., ltd.) respectively, without breaking vacuum. Finally, a 120 nm thick Ag electrode at a rate of 1.5 Å/s was deposited to complete the devices for current density-voltage (J-V) measurements.

Fabrication of perovskite solar cells by spin-coating
The perovskite precursor solution was prepared using the composition detailed previously, dissolved in a 10:1 (v/v) solvent mixture of DMF and NMP, and stirred overnight. The preparation of the NiOx and Py3 based SAM layers follows the aforementioned procedures. The filtered perovskite precursor solution was spin-coated onto the prepared substrate at 4000 rpm for 40 seconds. During the spinning process, 150 µL of ethyl acetate (EA) was rapidly dispensed as an antisolvent at the 20 s during the spinning step. Subsequently, the film was annealed at 130°C for 5 min. To complete the device, the remaining functional layers were then deposited using the methodologies described above.

Experimental groups definition. In this study, the intermediate phase films/wet films are defined as the films immediately after antisolvent/gas-quenching activation but prior to the thermal annealing. The Control group refers to perovskite devices/films fabricated via the blade-coating process without any additives.

Fabrication of blade-coated perovskite solar modules
Mini-modules (20.8 cm2) with ten subcells connected in series were fabricated on ITO glass with a size of 6.5 × 8.0 cm2. The series interconnection of the module was realized by P1, P2 and P3 lines, which were patterned using a laser scribing system (HANSPV PV-HL0303) with a wavelength of 532 nm, a power of 30 W and pulse width of 15 ps. The ITO substrate was pre-patterned for P1 (18 μm wide) at 7.5% laser power and a speed of 300 mm/s with a frequency of 269 kHz. The following steps were the same as the fabrication of small-area PSCs. For the preparation of Cs0.02FA0.98PbI3 thin film, the precursor concentration is 1.45 M. Additional 10 mol% PACl and 15 mol% MACl, 2 mg/mL LP, and 0.2 mg/mL ODADI were added to the precursor solution as additives. The perovskite precursor solution was then blade-coated on the substrate at 15 mm/s with the blade gap of 180 μm under dry air quenching. The films were annealed at 130°C for 5 min. The blade-coating processes were performed under ambient conditions with controlled humidity (~30%). The passivation layer, LiF (0.6 nm), C60 (40 nm), BCP layer (6 nm) were prepared by the same method as listed above. The P2 lines (48 μm wide) were patterned with 1.6% laser power at a speed of 500 mm/s and frequency of 500 kHz. After Ag electrode (120 nm) was deposited, the P3 lines (37 μm wide) were patterned with an average laser power of 2.8% at a speed of 500 mm/s and frequency of 500 kHz. The distance between the P1 and P3 lines is about 280 μm, the width of a single sub-cell (including dead area) is about 5.2 mm. the geometric fill factor is around 97.5%.

Device characterization
J-V characteristics of small-area photovoltaic cells were taken using a Keithley 2400 source measure unit under a simulated AM 1.5G illumination from an SS-X100R solar simulator (Enli Technology). The illumination light was calibrated to 100 mW/cm2 AM 1.5G using a silicon reference cell (Enli Technology). Typically, the devices were measured in reverse scan (1.20 V→0 V, step 0.02 V). All the devices were measured without pre-conditioning, such as light-soaking, and a bias voltage was applied. Steady-state power conversion efficiency was calculated by measuring stabilized photocurrent density under a constant bias voltage. A black metal mask (0.0665 cm2) was applied to define the testing area of PSCs.

Large area mini-modules were measured using an Oriel solar simulator equipped with a Keithley 2400 source meter at a light intensity of 100 mA/cm2, calibrated using a Si reference solar cell (Newport). PSMs were measured in forward and reverse scan modes with a bias voltage from 0 to 12 V at a scanning step of 50 mV and a delay time of 200 ms.

External quantum efficiencies (EQEs) were measured using an integrated system (Enlitech Technology) and a lock-in amplifier with a current preamplifier under short-circuit conditions.

Device stability tests
The stability test following the ISOS-L-2 protocol was conducted with continuous heating at ~50°C and under continuous AM 1.5G illumination (100 mW/cm2, white LED) at open-circuit condition. The PCEs of the devices were tracked over time, and the J-V measurements were performed after cooling the devices down to room temperature. The maximum power point tracking (MPPT) of the devices was conducted under AM 1.5G illumination at ~50°C. The voltage at the maximum power point was automatically adjusted and applied, and the power output of the devices was tracked over time. For the temperature control, we employed the Solar Cell Stability Test System PR-SCCS-C24Q from PURI Materials, in which the devices were placed on a heating stage, with a temperature detector attached and connected to an external proportional-integral-derivative (PID) controller. The stability test following the ISOS-D-2 protocol was conducted in the nitrogen atmosphere with continuous heating at ~85°C at open-circuit condition for the unencapsulated devices. For all the stability measurements, the films were then transferred to the atomic layer deposition (ALD) system for SnO2 layer deposition to replace the BCP layer.

Materials characterization
X-Ray Diffractometer (XRD): To evaluate the diffraction intensity of the intermediate solvate phase and crystallinity of perovskite films, perovskite layers were deposited on NiOx/SAM substrates following the spin- and blade-coating protocols described above based on the exact same DMF/NMP (10:1) precursor formulation. X-ray diffraction patterns were acquired upon antisolvent or gas quenching to capture the characteristic solvate peaks in the as-cast films and the crystallinity of the annealing films. The signals were collected in reflection mode at room temperature on a D8 advance diffractometer equipped with a 1D LynxEye detector using monochromated Cu-Ka (λ=1.5418 Å) radiation. Prior to XRD analysis, all samples were positioned at the same height, aligned with the edge of the holder’s top surface. The samples were subjected to a spin rate of 10 r/min to ensure averaged results.

Liquid chromatography-mass spectrometry (LC-MS): The NMP content in the perovskite wet films and annealed films was semi-quantified using an ultra-performance liquid chromatography (UPLC) system. Three substrates were placed into a 20 mL brown vial, followed by the addition of 2 mL of ACN. The perovskite films were detached from the ITO substrates through ultrasonic exfoliation and subsequently dissolved in ACN for UPLC analysis. All samples were prepared at a concentration of 1 mg/mL. The perovskite wet film samples were diluted 100 times prior to injection. Quantification analysis of NMP was carried out by an ultra-performance liquid chromatography instrument (ACQUITY UPLC, H-Class, Waters) coupled with a photodiode array detector (PDA) with BEH T3 column (1.8 μm, 2.1*100 mm, Waters). The mobile phase A is a water solution (0.1% formic acid, v/v) and mobile phase B is acetonitrile. The initial mobile phase is 20% B, increasing to 100% B in 2 min and maintaining for 2 min later. The post running time is 3.0 min. The elution is performed at 40°C with a flow rate of 0.4 mL/min. Single PDA channels at 330 nm were used for NMP. All data were collected and processed with Empower 3 software.

In-situ Grazing-incidence X-ray diffraction (In-situ GIXRD): The measurement was performed using a Bruker D8 Venture device. The samples were illuminated with a Cu Kα radiation source (λ = 1.5418 Å) at an incident angle of 0.2°. The scattered X-rays were detected using a Dectris Pilatus 2M photon-counting detector. To record the gas quenching and annealing process of the perovskite films, the perovskite precursor was first dipped onto the ITO substrate. Wet perovskite precursor films were then mounted on an insitu heating holder at 130°C and observed with a microscope (DM2500P, Leica) equipped with a hot stage (LTSE420, Linkam) and a camera (MicroPublisher 5.0 RTV, QImaging).

Fourier Transform infrared spectroscopy (FTIR): For FTIR measurements, samples without NMP were dissolved in a mixed solvent of 2-Me and NMP at a volume ratio of 1:2. The resulting solutions were then deposited onto high-resistance silicon substrates and dried at 130°C in a nitrogen glove box to remove the solvent before measurements. For samples containing NMP, the solution was spin-coated onto high-resistance silicon substrates and annealed at 80°C for 1 min before analysis. The FTIR spectra were collected at room temperature by an FTIR spectrometer (Thermo Fisher Nicolet iS50) equipped with a DTGS KBr detector. Spectral resolution was set to 1 cm−1, aperture to 4 mm, and spectra were acquired by averaging 64 scans.

The XAFS spectra at the Pb LIII-edge were characterized using a Rapid 2M instrument (Anhui Absorption Spectroscopy Analysis Instrument Co., Ltd.), equipped with a double Si(111) monochromator to monochromatize the X-ray white beam. Fourier-transformed radial distribution functions of k³-weighted Pb LIII-edge EXAFS spectra (k³χ(k)) were obtained in the k range of 3.0 to 9.0 Å−1 using a standard XAFS data analysis protocol. Energy calibration was performed with a Pb foil reference, and data processing and analysis were carried out using the Athena package.

Photoluminescence (PL) mapping: The measurement was performed using an alpha 300R (WITec GMBH, Germany) confocal Raman system. A diode-pumped solid-state laser (532 nm, cobalt laser) was focused on samples with a diffraction-limited beam size of 590 nm by a 50x long-focus objective (NA=0.55). The collected PL signal was dispersed using a UHTS 600 mm spectrometer and detected using an electron-magnified charge-coupled-device (EMCCD) thermoelectrically cooled to −60°C. Ultrafast PL imaging comprised a 200 nm step size and 10 ms integration time.

High-resolution X-ray photoelectron spectroscopy (XPS): The samples were loaded into the XPS instrument (Thermo Fisher ESCALAB Xi+), and an Al Kα (1486.6 eV) X-ray was used as the excitation source. For the ultraviolet photoelectron spectroscopy (UPS) measurements, a He discharge lamp, emitting ultraviolet energy at 21.2 eV, was used for excitation. All UPS measurements were performed using standard procedures with a −10 V bias applied between the samples and detectors. Clean gold was used as a reference.

Atomic force microscope (AFM) and its variants: For the AFM, conductive atomic force microscope (c-AFM) and Kelvin probe force microscope (KPFM) measurements of the Control and 2OH-based blade-coating perovskite films. The as-prepared samples were subsequently sent out for the c-AFM and KPFM measurements using the Jupiter XR Oxford Instruments. For all c-AFM measurements, a bias of 400 mV was applied.

Time-resolved photoluminescence (TRPL): For TRPL measurements, the perovskite layers were deposited onto the functional layers using the method indicated above. The sample was excited with a picosecond-pulsed diode laser (Pico-quant LDH 450), with a ∼70 ps pulse width and 20 MHz repetition rate, focused on the sample with a 100x objective (NA=0.90). The photoluminescence signal was acquired through the TCSPC strobe lock system. The total instrument response function (IRF) for the photoluminescence decay was less than 200 ps, and the temporal resolution was less than 30 ps. The energy density of the laser for TRPL measurements was set to be 26.46 nJ/cm2.

Transient photovoltage (TPV) and transient photocurrent (TPC) measurements: TPV and TPC measurements were performed by a photo-electrochemical measurement system (CIMPS-abs) and a high-power white light source (1000 W/m2) as a bias light source. A strongly attenuated laser pulse (550 nm) was used to generate a transient voltage (ΔV) of less than 20 mV.

Thermal admittance spectroscopy (TAS): The measurements were conducted using an impedance spectroscopy analyser (ZENNIUM, Zahner, Germany). The d.c. bias was set to 0 V, and the a.c. bias amplitude was fixed at 20 mV. The frequency range for the a.c. signal was scanned from 0.02 kHz to 2000 kHz, allowing for a detailed analysis of the frequency-dependent capacitance and corresponding trap state dynamics.

Electroluminescence (EL) Characterization: EL imaging was performed using a commercial EL inspection system (GSOLA). The perovskite modules were placed on a motorized translation stage and scanned using a 4K line-scan camera equipped with a custom optical lens module. The detection window was optimized for the 750–850 nm range to capture the perovskite emission. The devices were electrically driven by an integrated programmable DC source meter (Voltage: 0–300 V, Current: 0–5 A, Precision: ±0.01 V/A) in a constant current mode. The images were reconstructed from the line-scan data with a spatial resolution of better than 0.5 mm. To evaluate the macroscopic uniformity, the modules were scanned with a 5 ms exposure time (integration time) while being driven at a constant injection current of 0.2 × Isc.

Infrared Thermography (IRT): To investigate the thermal distribution and identify potential shunts or defects, thermal imaging was performed under dark conditions. The portable HIKMICRO P09 thermal imaging camera (smartphone-integrated module) featuring an infrared resolution of 96×96 pixels and a temperature range of −20 to 400°C was employed. We performed infrared thermography under a 6 V forward bias under dark conditions, where the voltage was supplied by a Keithley 2400 source meter.

DFT calculations
The binding energies of various systems were computed using density functional theory within the Gaussian 16 software package29. Geometry optimizations were performed employing the B3LYP hybrid functional30 paired with the def2TZVP basis set and supplemented with DFT-D3 dispersion correction31 to account for long-range dispersion interactions. The binding energy (Ebinding) was calculated by the following equation:

Ebinding = Esystem − Emolecule1 − Emolecule2 (1)

where Esystem is the total energy of the system, and Emolecule1 and Emolecule2 are the energies of molecules 1 and 2, respectively. All calculated energies are shown in Table S1.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This manuscript provides a significant advancement in the scalable fabrication of perovskite solar cells by offering a new\nperspective on a critical challenge: the persistent performance gap between laboratory-scale spin-coating and industrially\nviable blade-coating methods. The authors compellingly identify the prolonged solvent-precursor interaction time (τint), a\npreviously overlooked kinetic parameter, as a primary factor limiting the quality of blade-coated films. Their core finding\nreveals that an extended τint stabilizes a detrimental solvent adduct intermediate phase, which in turn increases residual\nsolvent content and degrades the crystallinity of the final film. To address this limitation, the authors introduce an elegant and\neffective \"dynamic coordination competition\" strategy, which successfully engineers a more favorable crystallization\npathway for high-quality perovskite films within the blade-coating process. The success of this method is\ndemonstrated by the outstanding power conversion efficiencies achieved: 26.5% for small-area devices (0.0665 cm2) and an impressive\n22.0% for large-scale sub-modules (722.4 cm2). This work holds significant implications for the scalable manufacturing and\ncommercialization of perovskite solar cells, offering valuable guidance for overcoming key industrial hurdles. Therefore,\nI recommend it for publication after the authors have addressed the following issues.\n1. While the authors have convincingly demonstrated the role of the 2OH additive in the precursor solution and during the\nfilm formation process, its eventual fate within the final, annealed film remains unclear. An analysis of its residual\nconcentration and spatial distribution would be highly valuable.\n2. The manuscript proposes the coordination competition strategy as a \"universal kinetic knob\" for controlling crystallization\nin scalable perovskite fabrication. However, the supporting evidence is currently limited to a single, high-performance\nperovskite composition (Cs0.02FA0.98PbI3) prepared with a specific NMP-based solvent system. The applicability of this\nmethod to other widely used formulations, such as mixed-halide perovskites or the prevalent DMF/DMSO solvent systems,\nhas not yet been demonstrated. Therefore, while the strategy is shown to be highly effective for the reported system, further\ninvestigation across a broader range of precursor chemistries and processing conditions is necessary to fully substantiate\nthe claim of universality.\n3. The central thesis of manuscript posits that the observed improvements are driven by a \"coordination competition\"\nmechanism, wherein the hydroxyl groups of the 2OH additive outcompete the NMP solvent for Pb2+. However, as a\nquaternary ammonium salt, the 2OH additive may also introduce other significant physicochemical effects within the\nprecursor solution. These could include alterations to the solution's viscosity and surface tension, which are known to\ninfluence nucleation and crystal growth dynamics. Could the authors elaborate on how they were able to decouple these\npotential synergistic contributions from the primary coordination competition mechanism?\n4. The data systematically presented in Figure 3 convincingly demonstrate that the number of hydroxyl (-OH) groups is a\ndominant factor governing the additive's effectiveness. The results consistently show a stronger coordination effect and\nimproved crystallization control as the number of -OH groups increases from zero to two. This clear trend raises a critical\nquestion: is the beneficial effect of this strategy directly proportional to the number of hydroxyl groups?\n5. The manuscript posits that the PbI2-NMP solvent adduct intermediate phase is detrimental to the final film quality, a\nconclusion supported by observations of increased residual solvent and reduced crystallinity in blade-coated films where\nthis phase is prominent. This finding appears to stand in contrast to a significant body of literature suggesting that the\nformation of an intermediate phase can be beneficial, for instance, by lowering the nucleation energy barrier for the\nperovskite phase (e.g., Science, 2021, 372, 1327-1332). Could the authors, therefore, elaborate on their perspective\nregarding this apparent dichotomy? Specifically, what factors, in their view, determine whether a given intermediate phase is\nadvantageous or disadvantageous for achieving high-quality crystallization?\n6. The manuscript presents compelling operational stability data, demonstrating the enhanced durability of the 2OH-treated\ndevices under continuous one-sun illumination while tracking the maximum power point at approximately 50 °C. While these\nresults are convincing, it is suggested that the authors supplement the operational data with results from other key stress\ntests, such as intrinsic thermal stability. Secondly, the External Quantum Efficiency (EQE) spectra for the champion devices\nare not presented. Providing the EQE spectrum is crucial for independently verifying the accuracy of the short-circuit current\ndensity (JSC) values reported in the J-V tests.", "reviewer_2": "In the work \"Suppressing Solvent Adducts via Coordination Competition Enables Scalable Perovskite Photovoltaics\" the\nauthors describe how the introduction of bis(2-hydroxyethyl) dimethylammonium chloride to a double cation perovksite\nsolution with the solvents 2-Me and NMP can impede an unvaforable PbI2:NMP solvent phase and thus stablize the\nprecursor solution to yield superior crystallization and phase purity of the resulting perovskite films. The evidence for the\ninteraction between NMP and 2OH groups appears convincing due to a variety of\nmeasurements and DFT calculations. The reported device performances are impressive, the scaling losses are state-of-the-art and the large area devices shown have the active area correctly specified.\nNevertheless, I am afraid, I cannot recommend the work for publication in its current state to meet the high standards of the\njournal. There are two main arguments for this:\n1. Two of the main hypotheses of the work are not properly tested (or not correctly posed).\nThe authors write:\n\"Here, we identify the solvent-precursor interaction time (τint) in the wet film as the missing link. During blade coating, the\nslow solvent evaporation rate prolongs τint, stabilizing the lead halide•N-methyl-2-pyrrolidone (NMP) adduct, locking in\nsolvent residue, and ultimately compromising film crystallinity. To overcome this bottleneck, we devise a dynamic\ncoordination competition strategy, employing the hydroxyl-terminated molecular that ooutcompetes NMP for Pb2+\ncoordination.\"\nYet, the time parameter (τint) is no-where determined nor properly compared to a reference that would justify the authors\nclaim of having identified τint as the principal cause of upscaling difficulties with perovskite solar cells. Another issue with\nthis claim is that \"missing link\" insinuates that the interaction time would be the main issue in general of up-scaling of\nperovskite solution processes, while it might only be applicable to the specific precursor solution and drying method the\nauthors employ.\nTherefore, I would like to give the authors two choices to implement a revision of these shortcomings.\nChoice a): Drop or replace the hypothesis.\nWhat I perceive when I see the authors data and provided evidence is not the determination of an interaction time parameter,\nbut rather \"intermediate phase engineering for blade-coated PSCs\". In fact, there are several reports that did similar\nanalyses, sometimes revealing beneficial impact of certain intermediate phases, sometimes\ndetrimental. Examples are https://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.202500536\nhttps://www.nature.com/articles/s41563-022-01399-8\nhttps://pubs.acs.org/doi/10.1021/jacs.4c14955\nIt is in this context that the authors could reformulate/re-analyse their data. If they choose this route, they should present the\nevidence of prior works on the topic accurately in the introduction, and then build on the state-of-the-art here to showcase\nhow their work for their particular precursor extents the state-of-the-art. I would, in this case, like to motivate the authors to\nredesign their introduction and manuscript to meet the new claims.\nChoice b): Properly provide evidence for their hypothesis.\nIf the authors prefer to properly test their hypothesis about the time-parameter, they should i) attempt at quantifying τint and ii)\nseparate its impact from the effects of applying a different\ncoating technique and iii) applying antisolvent quenching as\nopposed to gas quenching. These considerations would require\ni) Showcase that in the case of spin coating the same precursor solution, τint is really the cause. This would imply that films\nspin-coated longer before antisolvent quenching would have inferior quality. This should be quantified by measuring the\ntime between antisolvent applciation and starting of the coating. In addition, it is not clear from the manuscript if the\nmeasurements on the spin-coated films were performed before or after antisolvent application.\nii) Showcase with a proper reference that the spin-coated devices under similar conditions of gas quenching as in the main\nexperiment have the same issues of NMP-PbI2 intermediate phase formation that can be solved by the proposed molecule\nalso for the case of spin-caoting.\niii) Try to apply antisolvent quenching or a similar method to a blade-coated sample before the intermediate phase forms.\nAccording to their data, the authors have 30s before the intermediate phase formation happens. This is enough time to\ntransfer a miniature blade coated sample onto a spin coater and perform antisolvent quenching/or transfer the sample to an\nantisolvent bath.\nThe second hypothesis is when the authors state:\n\"We identify the prolonged solvent-precursor contact interaction time (τint) as a fundamental bottleneck limiting the\nperformance of scalable blade coating devices,\"\nEven when ignoring the issue with tint discussed above, and replacing it with another viable statement, what the authors\ndescribe is not \"a fundamental bottleneck limiting the performance of scalable devices\". This would only be true if the\n\"scalable\" is synonymous with \"blade-coated\". To properly test that the intermediate phase would be a bottle neck for\n\"scalability\", the authors should fabricate scaled-up reference devices and show that their method offers superior scalability.\nIn contrast, What they describe in the manuscript is only to compare a small-scale control device, with a small-scale blade\ncoated device. They do not analyse any scalability-related challenges such as module scribing, defect analyses over the\narea, hot-spots and morphological inhomogeneiety. Nor do they provide necessary measurements that can estimate\nlayer inhomogeneity on large scales, such as EL/PL imaiging, LBIC or thermography imaging. Even after multiple reads, it is still\nunclear to me what the control device actually is. Is it a spin-coated or a blade-coated device? (see next point).\n2. In many instances, the authors give insufficient and very unspecific info about their samples and measurement\ntechniques, which not only puts in peril any effort to reproduce the work, but also does not correspond to high-quality\nscientific writing. References to later parts of the manuscript are completely missing, which is why I had to use the search\nfunction to find info about a certain method everywhere. In a well-written manuscript, all specific info about a technique or\nsample mentioned should be included directly where it is mentioned or referenced appropriately. In addtion, the overall\ninattention to detail of how experiments are described gives the strong impression that the presented results, although\nimpressive, will be hard, if not impossible to reproduce by any group.\nI will outline the general point above in several instances:\n- Almost directly after the introduction, the authors start by writing\n\"The perovskite films fabricated by spin-coating.\"\nIt is not clear to the reader which films they write about, since no indication is given as to where it is described how these\nfilms were made. By searching the paper for the term \"spin-coating\" there is only one instance of sample preperation by\nspin-caoting for FTIR not the XRD samples they are writing about. Proper reference or information is missing on any\nfabrication details!\nthe authors continue by writing\n\"In intermediate wet films\".\nThis is a very unspecific term. A lot more information would help to understand how these films were made. Where are the\nroutines for producing theses intermediate films? For spin coating, does intermediate mean before or after the antisolvent\nwas applied? How do these films differ from the normal, complete fabrication? How were the films transferred to the\nmeasurement equipment and how long did this take? At which stage in the drying/morphology formation do the authors\nestimate the measurement to take place? Can the authors do these measurements at different times to rule out the impact of\ntime on their claims and data?\n- The authors continue by writing\n\"Subsequently, we measured the NMP content in the intermediate phase wet films prepared by different methods using\nLiquid Chromatography-Mass Spectrometry (LC-MS, Fig. 1c, Supplementary Fig. 1). By fitting the peak area, we observed\nthat the NMP content in the blade-coating films was significantly higher than in the spin-coated ones (Supplementary Fig.\n2a). This difference may arise from the prolonged solvent-precursor interaction time in blade-coating.\"\nAlthough I really like the idea to measure the NMP content in this way, I have several detailed questions, that I could not find\nanswered in the manuscript nor in the supplementary.\nHow did the authors extract the material to prepare it for LC-MS? Which solvent did they use? What impact could this have?\nHow did the authors make sure that the difference in \"NMP content\" is not just due to a thicker, total film produced typically\nby blade coating? What was the impact of the sample area and film thickness irregularity? I did not find any reference in the\nwhole manuscript discussing film thicknesses. What is the measurement error of the technique? How many films were\nmeasured and can the authors rule out statistical error of the measurements? In Figure 2a, the authors write \"spin coating\"\nand \"blade coating\". Was the spin-coated film already quenched or not? If it was quenched with antisolvent, it is no wonder\nthat there would be less NMP inside the film. Gas and antisolvent quenching would further not be comparable in this case\nanyway, since the antisolvent would wash out most of the NMP and the present antisolvent changes the morphology\nformation completely. In Figure S2a, the measurement for \"blade-coating\" is at an a.I. value of about 3.5e3 a.u., while in\nFigure 2S b the \"control\" datapoint is at 4.3e3 a.u., why are these not the same? How did the authors make sure that the\nfilms \"control\" and \"2OH\" had exactly the same time to dry before the measurement? How did they make sure that both films\nhad the same thickness?\n- The authors write\n\"We fabricated devices with an ITO/SAM/PVK/C60/BCP/Ag structure and assessed their performance using additives with\nvarying numbers of OH groups.\" They do not give any reference as to which SAM they are using and where the device\nfabrication is described. The architecture written in these terms is very unspecific. There probably more than 10 choices for\nfilling \"SAM\". So, I had to search the manuscript to answer this question. In the part \"Fabrication of inverted perovskite solar\ncells devices\", the authors write\n\"Then the substrate was spin-coated with a thin layer of NiOx nanoparticle film (20 mg/ml NiOx water solution) at 1500 rpm\nfor 30 s, and annealed in ambient air at 125 °C for 10 min. 0.5 mg/ml Py3 in mixed solvent of methanol and DMF at a volume\nratio 2:1 was deposited on the NiOx at 3000 rpm for 40 s. \"\nNot only was NiOx missing in the above described architecture. Furthermore, the NiOx nanoparticle solution is not\nmentioned nor specified in the \"Materials\" part. The same is true for \"Py3\", which is mentioned only once in the manuscript\nand I estimate is 2-(pyren-1-yl)ethyl)phosphonic acid from https://www.nature.com/articles/s41586-024-07712-6. The\nmissing attention on details shows that these are probably not the only inconsistencies and the reproduciblity of the results\nby other research groups is highly questionable.\n- The authors write in the fabrication section\n\"The filtered perovskite precursor solution was then blade-coated on the substrate at 15 mm/s with the blade gap of 160 μm\nunder dry air quenching.\"\nTo reproduce the authors' results, they should provide more details about the quenching method they employed. The\nfollowing questions should be answered specified:\n-> Where was the air quench setup situated with respect to the coating: Distance from the coating and height above the\nsample\n-> What was the type model of air knife or nozzle geometry used: Slot-width and slot height\n-> What was the speed of the air exiting the nozzle. This can be described by working and static pressure values, or in the\nideal case, by measuring the flow rate of air that comes through the nozzle.\nIf they do not provide these parameters, the only way of ensuring reproduciblity is to share a sketch with dimensions and/or a\nphotograph of their setup and share a video of their fabrication process. This is also be helpful to understand what they\nmean by \"wet\" or \"intermediate\" film.\n- The authors write:\n\" Between each sub-cell, P1, P2, and P3 lines were laser-scribed (HANSPV PV-HL0303) to form the typical series-\nconnection of perovskite solar modules. \"\nThis is very spare information about how these lines were scribed.There is a lot of information about the laser scribing\nmissing that would be necessary for reproducing these results. Further, there is not\ncharacterization of the scribing lines (optical, SEM micrsocopy,etc..), there is no characterization of the homogeneity of the module looking for hot spots and\nirregularities such as EL/PL mapping, LBIC or thermography. In a paper that has \"scalable\" in the title and discusses module\nfabrication, I would expect more information both on the scribing, which is not trivial, and on the estimation of scaling losses!\nSee. e.g.\nhttps://onlinelibrary.wiley.com/doi/full/10.1002/pip.3489\nhttps://advanced.onlinelibrary.wiley.com/doi/full/10.1002/aenm.202400115\nThere are several other small details to correct:\n- The 2-ME solution the authors employ is known for degradation over time. The authors should make sure that non of the\neffects they observe comes from degradation of the solution. They should provide the time between the experiment and the\npreparation of the solution\n- The authors mention several times room-temperature, but did not specify exactly at which temperature they operate at.\n-Grammar and Spell check: In the above example\n\"employing the hydroxyl-terminated molecular that ooutcompetes NMP\"\nyou find a typo and \"molecular\" instead of \"molecule\". Please run a spell and grammar checker over your manuscript.\n- In Figure 4f, the authors show Normalized PCE. They must show absolute PCE instead, since relative PCE can be\nmisleading.", "reviewer_3": "This article makes a significant contribution to perovskite photovoltaics by identifying τint as a critical parameter and\ndemonstrating that coordination competition enables high-performance linear printed devices. The authors identify a\npreviously overlooked kinetic parameter governing film quality in blade-coating processes and propose a coordination\ncompetition strategy using bis(2-hydroxyethyl) dimethylammonium chloride (2OH) to address this challenge. The material\ncharacterization is sound, especially FTIR and crystallography studies , though statistical rigor for large-area devices can\nadd value to a certain extent. The work's practical impact and mechanistic insights make it suitable for high-impact\npublication following the recommended revisions. The efficiency of 26.5% is rather impressive with blade-coated devices,\nbut an independent certification is beneficial to demonstrate the state-of-the-art performance of the blade-coated device,\nespecially considering the impact of the journal here. I have a few major queries from the scientific front before\nrecommending the manuscript for publication in Nature Communications.\nComments for authors:\n1. The authors made a few typos, namely “hydroxyl-terminated molecular that ooutcompetes NMP”, which should be\n“hydroxyl-terminated molecule that outcompetes”. Additionally, it would be beneficial to introduce the molecule in this\nintroductory paragraph, explicitly stating its chemical name at the very least.\n2. Do PACl and MACl impact the crystallization rate by controlling the intermediate adducts? Could the authors clarify the\nrole of such high mol% additives alongside 2OH molecule? What happens in the absence of PACl or MACl but in the\npresence of 2OH? Do you expect them to behave similar to 0OH molecule used in the study?\n3. The authors should demonstrate the difference in concentration 2OH group (PbI2-2OH-NMP) and its impact on C=O\nstretching vibration peaks by showing the peak-shift evolution with different concentrations of 2OH. The concentration of\n2OH in relation to other compounds used for FTIR measurements should also be mention in detail.\n4. Why does 0OH molecules increase NMP retention in LC-MS analysis in Fig. S11. Does PACl and MACl have a similar\neffect?\n5. Can 2OH completely replace NMP completely? Can the authors shed some insights into this process?\n6. The authors should mention concentrations of 0OH, 1OH and 2OH used for statistics in Fig S13.\n7. The authors should display the statistics obtained for large-area devices with and without control. This is important to\nunderstand the true potential of the additive.\n8. Finally, please make a comparison table comparing the performance of particular bandgap blade-coated devices with the\nliterature, so the reader could get a sense of state-of-the-art devices."}, "author_response": "Response Letter to Referees\n(Manuscript# NCOMMS-25-68139)\nBased on the referees’ comments, we have provided additional results and revised the manuscript\naccordingly. Via the supplementary data and analysis, we believe that we have fully addressed the\nconcerns raised in the reviews. Detailed point-to-point replies to the reviews along with the\nchanges we have made in the manuscript and Supplementary Materials are provided below.\n(Notes: the figures used for the replies are labeled as Fig. R# in sequence. For the convenience of\nthe reviewers, at the end of each piece of reply, we quoted the figures and texts that we have\nchanged in the manuscript and the Supplementary Materials.)\nReviewer #1:\nThis manuscript provides a significant advancement in the scalable fabrication of perovskite solar\ncells by offering a new perspective on a critical challenge: the persistent performance gap between\nlaboratory-scale spin-coating and industrially viable blade-coating methods. The authors\ncompellingly identify the prolonged solvent-precursor interaction time (τ ), a previously\nint\noverlooked kinetic parameter, as a primary factor limiting the quality of blade-coated films. Their\ncore finding reveals that an extended τ stabilizes a detrimental solvent adduct intermediate phase,\nint\nwhich in turn increases residual solvent content and degrades the crystallinity of the final film. To\naddress this limitation, the authors introduce an elegant and effective “dynamic coordination\ncompetition” strategy, which successfully engineers a more favorable crystallization pathway for\nhigh-quality perovskite films within the blade-coating process. The success of this method is\ndemonstrated by the outstanding power conversion efficiencies achieved: 26.5% for small-area\ndevices (0.0665 cm2) and an impressive 22.0% for large-scale sub-modules (722.4 cm2). This\nwork holds significant implications for the scalable manufacturing and commercialization of\nperovskite solar cells, offering valuable guidance for overcoming key industrial hurdles. Therefore,\nI recommend it for publication after the authors have addressed the following issues.\nReply: We are sincerely grateful to the reviewer for the support towards the potential publication\nof our manuscript. We have carefully considered all the comments and suggestions from the\nreviewer and revised our manuscript accordingly.\n1.While the authors have convincingly demonstrated the role of the 2OH additive in the precursor\nsolution and during the film formation process, its eventual fate within the final, annealed film\nremains unclear. An analysis of its residual concentration and spatial distribution would be highly\nvaluable.\nReply: We thank the reviewer for the suggestion. To determine the residual presence of the\nmolecule, we performed thermogravimetric analysis (TGA) on both the neat 2OH and the\nannealed 2OH-perovskite powder in Fig. R1a. Samples were heated to 130 ℃ at 10 ℃/min, held\nfor 10 min, and then raised to 400 ℃ at 20 ℃/min. The neat 2OH molecule exhibits minor mass\n1\nloss (~2.3%) below 100 ℃, attributed to desorbing moisture, but maintains thermal stability\nthroughout the annealing temperature (130 ℃). Decomposition initiates only near 250 ℃.\nConsistently, the 2OH-containing perovskite powder shows no measurable mass loss at the 130 ℃\nannealing temperature. This confirms that the additive is non-volatile under our processing\nconditions and does not evaporate during film formation.\nWe elucidated precise spatial distribution of the residues using time-of-flight secondary ion mass\nspectrometry (ToF-SIMS). Comparing the depth profiles in Fig. R1b (control) and Fig. R1c\n(target), the 2OH+ signal is sharply confined to the uppermost surface of the perovskite film,\nshowing negligible penetration into the bulk layer. This segregation behavior is visually\ncorroborated by the 3D ion maps in Fig. R1d-e. The data indicates that the molecules are sterically\nexcluded from the perovskite lattice and consequently accumulate at the grain boundaries on film\nsurfaces.\nFig. R1 a, TGA curves of pure 2OH molecules and annealed 2OH-perovskite powders. Samples\nwere heated to 130 ℃ at 10 ℃/min, held for 10 min, and then raised to 400 ℃ at 20 ℃/min. The\ndecomposition of pure 2OH occurs at approximately 250 ℃. The 2OH-perovskite powder exhibits\nno weight loss at the 130 ℃ annealing temperature. b-e, ToF-SIMS depth profiles (b, c) and 3D\nion maps (d, e) for the control and 2OH-treated films, respectively. The 2OH+ signal is exclusively\ndetected at the surface of the treated film.\n2.The manuscript proposes the coordination competition strategy as a “universal kinetic knob” for\ncontrolling crystallization in scalable perovskite fabrication. However, the supporting evidence is\ncurrently limited to a single, high-performance perovskite composition (Cs FA PbI ) prepared\n0.02 0.98 3\nwith a specific NMP-based solvent system. The applicability of this method to other widely used\nformulations, such as mixed-halide perovskites or the prevalent DMF/DMSO solvent systems, has\nnot yet been demonstrated. Therefore, while the strategy is shown to be highly effective for the\nreported system, further investigation across a broader range of precursor chemistries and\nprocessing conditions is necessary to fully substantiate the claim of universality.\nOur approach targets the fundamental kinetics of meniscus-guided coating: the 2OH molecule\nmodulates the stability of the intermediate phase by competitively inhibiting the formation of\noverly robust lead halide-solvent adducts. This interaction accelerates solvent removal and\nestablishes a superior crystallization template. Since this mechanism relies on basic coordination\nchemistry, we hypothesized it would remain effective across various perovskite formulations. To\nvalidate this, we applied the optimized protocol to two distinct narrow-bandgap compositions: a\ntriple-cation formulation MA Cs FA PbI and a mixed-halide system\n0.05 0.02 0.93 3\n(Cs FA PbI ) (MAPbBr ) . The statistical distributions in Fig. R2 and Fig. R3 reveal\n0.02 0.98 3 0.98 3 0.02\nconsistent performance enhancements across all photovoltaic metrics for both compositions,\nmirroring our initial findings. We then tested the robustness of this strategy against alternative\nsolvent environments. Replacing the standard host with a 2-pyrrolidone (PDI) coordinating\nsolvent system yielded comparable improvements, as detailed in Fig. R4. These parallel gains\nconfirm that the 2OH strategy is a generalized solution for intermediate phase engineering in\nscalable fabrication, functioning independently of specific cationic ratios or solvent choices.\nFig. R2 Statistical distributions of performance parameters for control, and 2OH-treated\nMA Cs FA PbI devices.\n0.05 0.02 0.93 3\nFig. R3 Statistical distributions of performance parameters for control, and 2OH-treated\nmixed-halide devices with composition (Cs FA PbI ) (MAPbBr ) devices.\n0.02 0.98 3 0.98 3 0.02\nprocessed via the 2-pyrrolidone (PDI) coordinating solvent system.\nWe have modified the manuscript and supplementary materials as follows:\n“Extending the strategy to triple-cation and mixed-halide compositions (Supplementary Fig. 23,\n24), alongside alternative 2-pyrrolidone solvent systems (Supplementary Fig. 25), yields\nconsistent performance enhancements that validate its broad applicability.\nSupplementary Fig. 23 Statistical distributions of performance parameters for control, and\n2OH-treated MA Cs FA PbI devices.\n0.05 0.02 0.93 3\nSupplementary Fig. 24 Statistical distributions of performance parameters for control, and\n2OH-treated mixed-halide devices with composition (Cs FA PbI ) (MAPbBr ) devices.\n0.02 0.98 3 0.98 3 0.02\n2OH-treated devices processed via the 2-pyrrolidone (PDI) coordinating solvent system.\nPreparation of perovskite precursors and films\nFor the preparation of perovskite films with a composition MA Cs FA PbI , 1.65 M\n0.05 0.02 0.93 3\nperovskite precursor solution was prepared by dissolving MAI, FAPbI and CsPbI powder in\n3 3\nmixed solvent of 2-Me and NMP at volume ratio 10:1. Additional 10 mol% PACl and 15 mol%\nMACl, 2 mg/mL LP and 0.2 mg/mL ODADI were added to the precursor solution as additives.\nThen the filtered perovskite precursor was blade-coated onto the substrates with a gap of 120 μm\nat a coating speed of 15 mm/s under dry air quenching. The blade-coating processes were\nperformed under ambient conditions with controlled humidity (~30%). The wet perovskite films\nwere then transferred onto a hot plate and annealed at 130 ℃ for 5 min in air.\nFor the preparation of perovskite films with a composition (Cs FA PbI ) (MAPbBr ) ,\n0.02 0.98 3 0.98 3 0.02\n1.65 M perovskite precursor solution was prepared by dissolving FAPbI , CsPbI and MAPbBr\n3 3 3\npowder in mixed solvent of 2-Me and NMP at volume ratio 10:1. Additional 10 mol% PACl and\n15 mol% MACl, 2 mg/mL LP and 0.2 mg/mL ODADI were added to the precursor solution as\nadditives. Then the filtered perovskite precursor was blade-coated onto the substrates with a gap of\n120 μm at a coating speed of 15 mm/s under dry air quenching. The blade-coating processes\nwere performed under ambient conditions with controlled humidity (~30%). The wet perovskite\nfilms were then transferred onto a hot plate and annealed at 130 ℃ for 5 min in air.\nFor the preparation of perovskite films with a composition Cs FA PbI , 1.65 M perovskite\n0.02 0.98 3\nprecursor solution was prepared by dissolving FAPbI and CsPbI powder in mixed solvent of\n3 3\n2-Me and PDI at volume ratio 12:1. Additional 10 mol% PACl and 15 mol% MACl, 2 mg/mL LP\nand 0.2 mg/mL ODADI were added to the precursor solution as additives. Then the filtered\nperovskite precursor was blade-coated onto the substrates with a gap of 120 μm at a coating speed\nof 15 mm/s under dry air quenching. The blade-coating processes were performed under ambient\nconditions with controlled humidity (~30%). The wet perovskite films were then transferred onto\na hot plate and annealed at 130 ℃ for 5 min in air.\n3.The central thesis of manuscript posits that the observed improvements are driven by a\n\"coordination competition\" mechanism, wherein the hydroxyl groups of the 2OH additive\noutcompete the NMP solvent for Pb2+. However, as a quaternary ammonium salt, the 2OH\nadditive may also introduce other significant physicochemical effects within the precursor solution.\ninfluence nucleation and crystal growth dynamics. Could the authors elaborate on how they were\nable to decouple these potential synergistic contributions from the primary coordination\ncompetition mechanism?\nReply: We thank the reviewer for this insightful and critical question. The quaternary ammonium\nsalts (QAS) can indeed introduce significant physicochemical changes to a precursor solution,\nincluding alterations to viscosity and surface tension, as demonstrated in the literature (Nature\nEnergy, 2018, 3, 7, 560-566). To decouple generic physicochemical alterations-such as viscosity\nor surface tension modifications from specific chemical interactions, we designed a comparative\nstudy using a homologous series of quaternary ammonium salts: Tetramethylammonium chloride\n(0OH), Choline chloride (1OH), and bis (2-hydroxyethyl) dimethylammonium chloride (2OH).\nThese analogues share an nearly identical cationic core and chloride counter-ion, differing strictly\nin their hydroxyl functionality (n=0, 1, 2). If the observed enhancements stemmed from\nnon-specific rheological changes induced by the salt, one would anticipate comparable impacts\nacross the series regardless of the hydroxyl count. The experimental outcomes reveal a strict\ndependence on the specific chemical structure. The 0OH variant yielded device metrics\nindistinguishable from the control, effectively ruling out the ammonium core or general solution\neffects as the primary drivers of film quality. Conversely, performance scaled directly with\nhydroxyl density, with 1OH providing moderate gains and 2OH delivering the optimal results.\nThis functional correlation isolates the hydroxyl moiety as the active agent, confirming that\nspecific coordination competition, rather than bulk solution modification, governs the\ncrystallization kinetics.\n4.The data systematically presented in Figure 3 convincingly demonstrate that the number of\nhydroxyl (-OH) groups is a dominant factor governing the additive's effectiveness. The results\nconsistently show a stronger coordination effect and improved crystallization control as the\nnumber of -OH groups increases from zero to two. This clear trend raises a critical question: is the\nbeneficial effect of this strategy directly proportional to the number of hydroxyl groups?\nReply: We thank the reviewer for this insightful question. The data in Figure 3 establishes a\ndistinct positive correlation between the number of hydroxyl groups and the effectiveness of\nadditive. The primary objective of this homologous series was to unambiguously isolate the\nfunctional moiety driving the performance, rather than to define a strict linear scaling law. The\n0OH variant functions as the definitive null control; its inability to enhance film quality confirms\nthat the quaternary ammonium core alone is chemically inert regarding the crystallization process.\nConsequently, the incremental performance gain observed from 1OH to 2OH serves as\nmechanistic validation. This trend confirms that the specific coordination capability of the\nhydroxyl group is the sole determinant of the improved kinetics, distinct from generic solution\nproperties.\n5.The manuscript posits that the PbI -NMP solvent adduct intermediate phase is detrimental to\n2\nthe final film quality, a conclusion supported by observations of increased residual solvent and\nreduced crystallinity in blade-coated films where this phase is prominent. This finding appears to\nstand in contrast to a significant body of literature suggesting that the formation of an intermediate\nphase can be beneficial, for instance, by lowering the nucleation energy barrier for the perovskite\n6\nphase (e.g., Science, 2021, 372, 1327-1332). Could the authors, therefore, elaborate on their\nperspective regarding this apparent dichotomy? Specifically, what factors, in their view, determine\nwhether a given intermediate phase is advantageous or disadvantageous for achieving high-quality\ncrystallization?\nReply: We thank the reviewer for raising this excellent point. We share the view that intermediate\nphases often serve as beneficial templates for modulating grain growth, a concept well-established\nin recent literature (e.g., Joule, 2022, 6, 2, 315-339; Nature Materials, 2023, 22, 1, 73-83; Nature,\n2023, 624, 7992, 557-563). The determination of whether such a phase facilitates or hinders\nhigh-quality crystallization rests primarily on the kinetics of solvent extraction inherent to the\nprocessing method. In spin-coating, the interplay of centrifugal force and antisolvent quenching\ndictates an aggressive extraction regime, forcing a rapid transition from the intermediate state to\nthe perovskite phase. Conversely, scalable blade-coating relies on slower, evaporation-driven\nremoval. Within this protracted kinetic window, the strong coordination of NMP forms a robust\nPbI -NMP adduct that persists excessively in the wet film. This thermodynamic stability becomes\n2\ndetrimental in two specific ways: Retarded Nucleation: High residual solvent content delays the\nonset of supersaturation, suppressing the formation of dense nucleation nuclei (Angewandte\nChemie International Edition, 2025, 64, 32, e202509459). Structural Defects: The persistent\nadduct effectively traps solvent within the matrix. Upon thermal annealing, the violent\nvolatilization of these trapped species induces pinhole formation (Energy & Environmental\nScience, 2025, 18, 9917-9926; ACS Energy Letters, 2024, 9, 7, 3418-3425). and degrades phase\npurity (Energy & Environmental Science, 2024, 17, 14, 5070-5079). In our NMP-based\nblade-coating system, the adduct is overly stable. Our coordination competition strategy\nspecifically targets this disparity, destabilizing the overly robust intermediate phase to accelerate\ncrystallization and match the drying dynamics of scalable fabrication.\n6.The manuscript presents compelling operational stability data, demonstrating the enhanced\ndurability of the 2OH-treated devices under continuous one-sun illumination while tracking the\nmaximum power point at approximately 50 ℃. While these results are convincing, it is suggested\nthat the authors supplement the operational data with results from other key stress tests, such as\nintrinsic thermal stability. Secondly, the External Quantum Efficiency (EQE) spectra for the\nchampion devices are not presented. Providing the EQE spectrum is crucial for independently\nverifying the accuracy of the short-circuit current density (J ) values reported in the J-V tests.\nSC\nReply: We thank the reviewer for these constructive suggestions. As suggested by the reviewer,\nwe performed the aging test of the unencapsulated devices at 85 ℃ in the dark condition to\nevaluate the intrinsic thermal stability of our devices. The degradation kinetics plotted in Fig. R5\nreveal a stark contrast: while the control devicesretained 85% of their initial efficiency after 550\nhours, the 2OH-modified devices exhibited superior resilience, maintaining over 92% of their\noriginal performance. This confirms that its enhanced intrinsic resistance to thermal stress. To\nvalidate the short-circuit current densities reported in the J-V measurements, we provide the\nexternal quantum efficiency (EQE) spectra in Fig. R6. The integrated short-circuit current density\n(JSC) values extracted from the external quantum efficiency (EQE) for our champion devices are\n25.1 mA/cm2 for the control device and 25.4 mA/cm2 for the 2OH device, which are in good\nagreement with J-V measurement.\nfollowing the ISOS-D-2 protocol.\nFig. R6 EQE spectra and corresponding integrated current densities for control and 2OH-treated\nchampion devices.\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows:\n“The devices at 85 °C thermal stress (ISOS-D-2 protocol) was also performed. The 2OH treated\ndevices maintained over 92% of their initial efficiency after 550 hours, whereas the device based\non control remained only 85% (Supplementary Fig. 33).\nThe integrated current density (J ) values derived from the EQE spectra were 25.1 mA/cm2 for\nSC\nthe control and 25.4 mA/cm2 for the 2OH treated PSCs, which match well with the J-V\nmeasurement (Supplementary Fig. 21).\nSupplementary Fig. 33 Statistical distributions of performance parameters for control, and\n2OH-treated devices processed via the 2-pyrrolidone (PDI) coordinating solvent system.\nand 2OH-treated champion devices.\nReviewer #2:\nIn the work \"Suppressing Solvent Adducts via Coordination Competition Enables Scalable\nPerovskite Photovoltaics\" the authors describe how the introduction of bis (2-hydroxyethyl)\ndimethylammonium chloride to a double cation perovksite solution with the solvents 2-Me and\nNMP can impede an unvaforable PbI :NMP solvent phase and thus stablize the precursor solution\n2\nto yield superior crystallization and phase purity of the resulting perovskite films. The evidence\nfor the interaction between NMP and 2OH groups appears convincing due to a variety of\nmeasurements and DFT calculations. The reported device performances are impressive, the\nscaling losses are state-of-the-art and the large area devices shown have the active area correctly\nspecified. Nevertheless, I am afraid, I cannot recommend the work for publication in its current\nstate to meet the high standards of the journal.\nReply: We thank the reviewer for the time and efforts in evaluating our manuscript. As per the\nreviewer’s concerns, we have carefully considered all the points raised and conducted experiments\nand analysis to address them. We have provided point-to-point replies below.\n1.There are two main arguments for this: Two of the main hypotheses of the work are not\nproperly tested (or not correctly posed). The authors write: \"Here, we identify the\nsolvent-precursor interaction time (τ ) in the wet film as the missing link. During blade coating,\nint\nthe slow solvent evaporation rate prolongs τ , stabilizing the lead halide•N-methyl-2-pyrrolidone\nint\n(NMP) adduct, locking in solvent residue, and ultimately compromising film crystallinity. To\novercome this bottleneck, we devise a dynamic coordination competition strategy, employing the\nhydroxyl-terminated molecular that ooutcompetes NMP for Pb2+ coordination.\" Yet, the time\nparameter (τ ) is no-where determined nor properly compared to a reference that would justify\nint\nthe authors claim of having identified τ as the principal cause of upscaling difficulties with\nint\nperovskite solar cells. Another issue with this claim is that \"missing link\" insinuates that the\ninteraction time would be the main issue in general of up-scaling of perovskite solution processes,\nwhile it might only be applicable to the specific precursor solution and drying method the authors\nemploy.\ndefinition of the solvent-precursor interaction time (τ ) may have implied a quantifiable\nint\nparameter amenable to direct chronometric measurement. We intended τ to define a kinetic\nint\nregime rather than a specific scalar value. We use τ to qualitatively distinguish between the\nint\nsolvent extraction mechanisms of spin-coating and blade-coating. In spin-coating, the combination\nof high centrifugal force and immediate antisolvent quenching creates an inherently brief τ ,\nint\nforcibly interrupting solvent-solute interactions to induce rapid supersaturation. Conversely,\nblade-coating relies on gas quenching. This inherently prolonged τ permits strong coordinating\nint\nsolvents like NMP to maintain sustained coordination with PbI , locking the wet film in a\n2\npersistent solvent-rich state. We did not seek to measure τ directly but rather to validate the\nint\nspecific consequences of this prolonged interaction. Figure 1 provides the empirical evidence:\nusing identical precursor formulations, the blade-coated wet films exhibit significantly stronger\nPbI -NMP solvate signatures compared to their spin-coated counterparts. This data confirms that\n2\nthe extended interaction window of the coating method directly causes the accumulation and\noverly stable intermediates. Our \"dynamic coordination competition\" strategy is designed\nspecifically to disrupt this stabilization during that prolonged window.\nWe posit that the management of τ represents a ubiquitous challenge in scalable fabrication,\nint\nextending beyond our specific chemical system or drying method. Recent literature substantiates\nthis view. Investigations into vacuum-flash processes (Energy & Environmental Science, 2025, 18,\n9917-9926; Energy & Environmental Science, 2025 (DOI: 10.1039/D5EE05421D). identify the\nprecise balance between supersaturation rate and coordination capability as the determinant for\nhigh-performance devices; a dynamic inextricably linked to τ . Similarly, research on\nint\nmechanical-chemical synthesis similarly targets this bottleneck, leveraging shear stress and\nvolatile precursors to circumvent prolonged solvent interactions (Nature Synthesis, 2025, 4,\n196-208.). In this context, the PbI -NMP adduct is merely the specific phenomenological\n2\nmanifestation within our system. The prolonged τ remains the fundamental, process-induced root\nint\ncause inherent to scalable coating methods, which our strategy specifically resolves.\n2.Therefore, I would like to give the authors two choices to implement a revision of these\nshortcomings. Choice a): Drop or replace the hypothesis. What I perceive when I see the authors\ndata and provided evidence is not the determination of an interaction time parameter, but rather\n\"intermediate phase engineering for blade-coated PSCs\". In fact, there are several reports that did\nsimilar analyses, sometimes revealing beneficial impact of certain intermediate phases, sometimes\ndetrimental. Examples are:\nhttps://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.202500536\nhttps://www.nature.com/articles/s41563-022-01399-8\nhttps://pubs.acs.org/doi/10.1021/jacs.4c14955\nIt is in this context that the authors could reformulate/re-analyze their data. If they choose this\nroute, they should present the evidence of prior works on the topic accurately in the introduction,\nand then build on the state-of-the-art here to showcase how their work for their particular\nprecursor extents the state-of-the-art. I would, in this case, like to motivate the authors to redesign\ntheir introduction and manuscript to meet the new claims.\nChoice b): Properly provide evidence for their hypothesis.\nattempt at quantifying τ and ii) separate its impact from the effects of applying a different\nint\ncoating technique and iii) applying antisolvent quenching as opposed to gas quenching. These\nconsiderations would require\ni) Showcase that in the case of spin coating the same precursor solution, τ is really the cause.\nint\nThis would imply that films spin-coated longer before antisolvent quenching would have inferior\nquality. This should be quantified by measuring the time between antisolvent applciation and\nstarting of the coating. In addition, it is not clear from the manuscript if the measurements on the\nspin-coated films were performed before or after antisolvent application.\nii) Showcase with a proper reference that the spin-coated devices under similar conditions of gas\nquenching as in the main experiment have the same issues of NMP-PbI intermediate phase\n2\nformation that can be solved by the proposed molecule also for the case of spin-caoting.\niii) Try to apply antisolvent quenching or a similar method to a blade-coated sample before the\nintermediate phase forms. According to their data, the authors have 30 s before the intermediate\nphase formation happens. This is enough time to transfer a miniature blade coated sample onto a\nspin coater and perform antisolvent quenching/or transfer the sample to an antisolvent bath.\nReply: We sincerely thank the reviewer for the thoughtful comments to help us validate our\ncentral hypothesis. We have opted for Choice (b) and performed the three specific experiments\nrequested to isolate the role of the solvent–precursor interaction time (τ ).\nint\ni. Quantifying the impact of τ via spin-coating delay.\nint\nWe first clarify that all spin-coated measurements in the original manuscript were performed after\nantisolvent application. While we initially defined τ as a kinetic regime to qualitatively\nint\ndistinguish between the solvent extraction mechanisms of spin-coating and blade-coating. we\nadopted the reviewer’s quantitative approach to isolate the temporal variable. We performed\nspin-coating experiments using the identical blade-coating precursor formulation but\nsystematically varied the delay prior to antisolvent dispensing (5 s to 25 s). As detailed in Fig. R7,\nwe observe a distinct, monotonic decline in both FF and PCE as the delay increases. This data\nprovides direct empirical confirmation that for NMP-based systems, the prolonged presence of the\nsolvent degrades the final film quality even by a matter of seconds. This mirrors the kinetic\nbottleneck inherent to the extended drying window of blade-coating.\nOC SC\ndevices subjected to varying delays prior to antisolvent quenching. The x-axis denotes the specific\ntime interval between the onset of the spin cycle and the antisolvent dispensing.\nii. Decoupling drying kinetics from coating mechanics.\nTo verify that the slow drying mechanism (rather than the coating tool itself) drives intermediate\nphase formation, we applied gas quenching (GQ) to spin-coated films (SC+GQ), mimicking the\nsolvent extraction kinetics of blade-coating. As displayed in Fig. R8a-d, it reveals that SC+GQ\ndevices suffer severe performance deficits compared to the standard antisolvent (SC+AS) control.\nX-ray diffraction of the corresponding wet films (Fig. R8e) confirms that this slow drying regime\nprecipitates a massive accumulation of the NMP-PbI intermediate phase.\nintroduction of the 2OH additive into the SC+GQ process significantly suppresses this\nintermediate phase intensity and recovers device metrics (V and FF).\nOC\nThis result demonstrates\nthat the approach is not limited to blade-coating but is effective for any process governed by slow\ndrying kinetics, specifically mitigating the excessive accumulation of overly stable NMP-PbI\n2\nintermediates.\nFig. R8. Statistical distributions of a, PCE, b, V , c, FF, and d, J for spin-coated devices\nOC SC\nprocessed via gas quenching (SC+GQ), gas quenching with 2OH modification (SC+GQ+2OH),\nand standard antisolvent quenching (SC+AS). e, X-ray diffraction patterns of the corresponding\nas-cast wet films highlighting the characteristic PbI -NMP solvate diffraction peak.\n2\niii. Feasibility of antisolvent quenching in scalable processing.\nWe subjected blade-coated wet films to a rapid antisolvent bath immersion using either\nchlorobenzene or ethyl acetate. As shown in Fig. R9 and Fig. R10 (Supplementary Video 1-2),\nthis abrupt solvent extraction induces catastrophic, uncontrolled nucleation, resulting in\nmacroscopically inhomogeneous films with inferior crystallization quality and photovoltaic\nperformance compared to the gas-quenching process. This failure highlights that simple\nantisolvent quenching is incompatible with the thick wet films typical of scalable fabrication.\nIt\nunderscores the necessity of our proposed strategy.\nimplementation of the antisolvent immersion method, where miniature wet blade-coated films\nwere transferred into (a) chlorobenzene (CB) and (b) ethyl acetate (EA) baths prior to intermediate\nphase consolidation. The lower insets display the front side and back side of the resulting annealed\nperovskite films, which exhibit visible macroscale inhomogeneities. The full dynamic processes\nhave been uploaded separately in Supplementary Video 1 (for CB) and Supplementary Video 2\n(for EA), respectively. c, d, Comparative optical images of the front side and back side of\nannealed films obtained via the standard gas-quenching process for the control (c) and\n2OH-modified (d) perovskite films.\nFig. R10 Photovoltaic performance statistics and crystallinity of blade-coated devices processed\nvia different quenching protocols. a-d, Distributions of (a) PCE, (b) V , (c) FF, and (d) J for\nOC SC\nstandard gas-quenched films (Control, 2OH) compared to films subjected to antisolvent\nimmersion in chlorobenzene (Control/CB) or ethyl acetate (Control/EA). e, XRD patterns of the\ncorresponding annealed perovskite films.\nspin-coating data (i) confirms that prolonged solvent interaction is intrinsically detrimental. The\ngas-quenched spin-coating data (ii) proves that our additive specifically resolves this kinetic issue.\nThe antisolvent bath failure (iii) demonstrates that the necessity of our strategy for upscaling.\nThese findings rigorously validate τ as the governing variable and coordination competition as\nint\nthe essential resolution for achieving this regulation.\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows:\nNotably, a coherent evidentiary chain validates τ as the governing variable. Prolonged solvent\nint\nresidence during spin-coating proves intrinsically detrimental (Supplementary Fig. 3), while\ngas-quenching exhibits kinetic bottlenecks that are specifically resolved by the additive\n(Supplementary Fig. 4). Moreover, the catastrophic nucleation induced by antisolvent baths\nconfirms that abrupt physical extraction is incompatible with scalable thick films (Supplementary\nFig. 5-6, Supplementary Video 1-2). This establishes coordination competition as the essential\nresolution for kinetic regulation.\nSupplementary Fig. 3 Statistical performance distributions of a, PCE, b, V , c, FF, and d, J\nOC SC\nfor spin-coated devices subjected to varying delays prior to antisolvent quenching. The x-axis\ndenotes the specific time interval between the onset of the spin cycle and the antisolvent\ndispensing.\ndevices processed via different quenching protocols. a-d, Distributions of (a) PCE, (b) V , (c) FF,\nOC\nand (d) J for standard gas-quenched films (Control, 2OH) compared to films subjected to\nSC\nantisolvent immersion in chlorobenzene (Control/CB) or ethyl acetate (Control/EA). e, XRD\npatterns of the corresponding annealed perovskite films.\nSupplementary Fig. 5 a, b, Representative frames extracted from the real-time recording the\nexperimental implementation of the antisolvent immersion method, where miniature wet\nblade-coated films were transferred into (a) chlorobenzene (CB) and (b) ethyl acetate (EA) baths\nprior to intermediate phase consolidation. The lower insets display the front side and back side of\nthe resulting annealed perovskite films, which exhibit visible macroscale inhomogeneities. The\nfull dynamic processes are documented in Supplementary Video 1 (for CB) and Supplementary\nVideo 2 (for EA), respectively. c, d, Comparative optical images of the front side and back side of\nannealed films obtained via the standard gas-quenching process for the (c) control and (d)\n2OH-modified perovskite films.\ndevices processed via different quenching protocols. a-d, Distributions of (a) PCE, (b) V , (c) FF,\nOC\nand (d) J for standard gas-quenched films (Control, 2OH) compared to films subjected to\nSC\nantisolvent immersion in chlorobenzene (Control/CB) or ethyl acetate (Control/EA). e, XRD\npatterns of the corresponding annealed perovskite films.\n16\n3.The second hypothesis is when the authors state: “We identify the prolonged solvent-precursor\ncontact interaction time (τ ) as a fundamental bottleneck limiting the performance of scalable\nint\nblade coating devices,” Even when ignoring the issue with tint discussed above, and replacing it\nwith another viable statement, what the authors describe is not “a fundamental bottleneck limiting\nthe performance of scalable devices”. This would only be true if the “scalable” is synonymous\nwith “blade-coated”. To properly test that the intermediate phase would be a bottle neck for\n“scalability”, the authors should fabricate scaled-up reference devices and show that their method\noffers superior scalability. In contrast, what they describe in the manuscript is only to compare a\nsmall-scale control device, with a small-scale blade coated device. They do not analyze any\nscalability-related challenges such as module scribing, defect analyses over the area, hot-spots and\nmorphological inhomogeneity. Nor do they provide necessary measurements that can estimate\nlayer inhomogeneity on large scales, such as EL/PL imaging, LBIC or thermography imaging.\nEven after multiple reads, it is still unclear to me what the control device actually is. Is it a\nspin-coated or a blade-coated device? (see next point).\nReply: We appreciate the reviewer’s constructive assessment regarding the validation of\nscalability validation. Acknowledging the necessity of module-level characterization, we have\ncomprehensively updated the manuscript to include large-area fabrication details and spatial\nhomogeneity analyses.\nFirst, we clarify that the \"Control\" device referenced throughout the manuscript refers exclusively\nto devices fabricated via blade-coating without the 2OH additive, ensuring a direct methodological\ncomparison for scalable process.\nWe now explicitly define the \"wet film\" state for this comparative analysis: for spin-coating, this\nrefers to the film immediately following anti-solvent dripping but prior to thermal annealing; for\nblade-coating, it denotes the film post-gas quenching but prior to annealing. This isolation allows\n16\nfor a direct assessment of the solvent retention differences between the two crystallization\nkinetics.\nTo validate the translation of this kinetic control to large-area fabrication, we fabricated perovskite\nmini-modules and detailed the laser scribing parameters (wavelength, power, frequency) for the\nP1, P2, and P3 interconnections in the revised Methods section. Optical microscopy (Fig. R11c)\nconfirms the geometric precision of the monolithic interconnects, revealing clean ablation lines\nwith a total dead-area width of approximately 280 µm.\nWe probed the macroscopic uniformity of these modules via electroluminescence (EL) mapping,\nacquiring images with a 5 ms exposure time under a constant injection current of 0.2 × Isc. The\ncontrol module (Fig. R11a, left) exhibits subdued luminescence with a speckled distribution of\ndark spots, indicative of widespread non-radiative recombination centers and film inhomogeneity.\nConversely, the 2OH-modified module (Fig. R11a, right) displays a consistently bright and\nspatially uniform emission profile across the sub-cells. This contrast confirms that the\ncoordination strategy effectively mitigates defect formation over large areas, significantly\nenhancing the optoelectronic uniformity of the blade-coated films.\nTo evaluate electrical integrity and potential shunting, we performed infrared thermography (IRT)\nunder a 6 V forward bias under dark conditions. The control module (Fig. R11b, left) manifests\ndistinct localized hot spots (bright regions), identifying specific low-resistance shunt paths and\nJoule heating defects. We acknowledge that the limited spatial resolution of the handheld thermal\nimage precludes the precise spatial localization of these hot spots. In sharp contrast, the\n2OH-target module (Fig. R11b, right) maintains a homogeneous thermal distribution across the\nactive area. This verifies that our strategy suppresses the localized overheating that typically\ncompromise the reliability of scalable blade-coated devices.\nCollectively, these optical, luminescent, and thermal characterizations provide robust evidence\nthat the 2OH additive resolves the fundamental homogeneity bottlenecks inherent to upscaling,\nvalidating the method’s applicability to module-level fabrication.\nFig. R11 a, Optical micrograph of the monolithic interconnection region for the perovskite\nmodule, detailing the P1, P2, and P3 scribing lines with a total dead area width of approximately\n280 µm. b, Comparative electroluminescence (EL) mapping images of the blade-coated control\n(left) and 2OH-modified (right) devices. c, Infrared thermal imaging profiles captured under dark\n17\nconditions with a 6 V forward bias of the blade-coated control (left) and 2OH-modified (right)\ndevices.\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows:\n“To evaluate the scalability, we fabricated perovskite mini-modules with an active area of 20.8 cm²\nfeaturing precise laser-scribed interconnects with a total dead-area width of approximately 280 µm\n(Supplementary Fig. 26a). Electroluminescence (EL) mapping captures the contrast in\nmacroscopic homogeneity; the unmodified blade-coated module exhibits subdued, speckled\nluminescence indicative of widespread non-radiative defects, whereas the 2OH-treated counterpart\ndisplays a consistently bright and uniform emission profile (Supplementary Fig. 26b). Infrared\nthermography (IRT) under forward bias further distinguishes the electrical integrity. Distinct\nlocalized hot spots revealing low-resistance shunt paths in the control are effectively eliminated in\nthe modified module (Supplementary Fig. 26c).\nSupplementary Fig. 26 a, Optical micrograph of the monolithic interconnection region for the\nperovskite module, detailing the P1, P2, and P3 scribing lines with a total dead area width of\napproximately 280 µm. b, Comparative electroluminescence (EL) mapping images of the\nblade-coated control (left) and 2OH-modified (right) devices. c, Infrared thermal imaging profiles\ncaptured under dark conditions with a 6 V forward bias of the blade-coated control (left) and\n2OH-modified (right) devices.\nFabrication of blade-coated perovskite solar modules\nMini-modules (20.8 cm2) with ten subcells connected in series were fabricated on ITO glass with a\nsize of 6.5 × 8.0 cm2. The series interconnection of the module was realized by P1, P2 and P3 lines,\nwhich were patterned using a laser scribing system (HANSPV PV-HL0303) with a wavelength of\n532 nm, a power of 30 W and pulse width of 15 ps. The ITO substrate was pre-patterned for P1\n(18 μm wide) at 7.5% laser power and a speed of 300 mm/s with a frequency of 269 kHz. The\nfollowing steps were the same as the fabrication of small-area PSCs. For the preparation of\nCs FA PbI thin film, the precursor concentration is 1.45 M. Additional 10 mol% PACl and 15\n0.02 0.98 3\nmol% MACl, 2 mg/mL LP, and 0.2 mg/mL ODADI were added to the precursor solution as\nadditives. The perovskite precursor solution was then blade-coated on the substrate at 15 mm/s\nwith the blade gap of 160 μm under dry air quenching. The films were annealed at 130 °C for 5\n18\nmin. The blade-coating processes were performed under ambient conditions with controlled\nhumidity (~30%). The passivation layer, LiF (0.6 nm), C60 (40 nm), BCP layer (6 nm) were\nprepared by the same method as listed above. The P2 lines (48 μm wide) were patterned with 1.6%\nlaser power at a speed of 500 mm/s and frequency of 500 kHz. After Ag electrode (120 nm) was\ndeposited, the P3 lines (37 μm wide) were patterned with an average laser power of 2.8% at a\nspeed of 500 mm/s and frequency of 500 kHz. The distance between the P1 and P3 lines is about\n280 μm, the width of a single sub-cell (including dead area) is about 5.2 mm. the geometric fill\nfactor is around 97.5%.\nMaterials characterization\nElectroluminescence (EL) Characterization: EL imaging was performed using a commercial EL\ninspection system (GSOLA). The perovskite modules were placed on a motorized translation\nstage and scanned using a 4K line-scan camera equipped with a custom optical lens module. The\ndetection window was optimized for the 750–850 nm range to capture the perovskite emission.\nThe devices were electrically driven by an integrated programmable DC source meter (Voltage: 0–\nreconstructed from the line-scan data with a spatial resolution of better than 0.5 mm. To evaluate\nthe macroscopic uniformity, the modules were scanned with a 5 ms exposure time (integration\ntime) while being driven at a constant injection current of 0.2 × Isc.\nInfrared Thermography (IRT): To investigate the thermal distribution and identify potential shunts\nor defects, thermal imaging was performed under dark conditions. The portable HIKMICRO P09\nthermal imaging camera (smartphone-integrated module) featuring an infrared resolution of 96 ×\n96 pixels and a temperature range of -20 to 400 °C was employed. We performed infrared\nthermography under a 6 V forward bias under dark conditions, where the voltage was supplied by\na Keithley 2400 source meter.\n4.In many instances, the authors give insufficient and very unspecific info about their samples\nand measurement techniques, which not only puts in peril any effort to reproduce the work, but\nalso does not correspond to high-quality scientific writing. References to later parts of the\nmanuscript are completely missing, which is why I had to use the search function to find info\nabout a certain method everywhere. In a well-written manuscript, all specific info about a\ntechnique or sample mentioned should be included directly where it is mentioned or referenced\nappropriately. In addition, the overall inattention to detail of how experiments are described gives\nthe strong impression that the presented results, although impressive, will be hard, if not\nimpossible to reproduce by any group. I will outline the general point above in several instances:\nAlmost directly after the introduction, the authors start by writing \"The perovskite films fabricated\nby spin-coating.\" It is not clear to the reader which films they write about, since no indication is\ngiven as to where it is described how these films were made. By searching the paper for the term\n\"spin-coating\" there is only one instance of sample preparation by spin-coating for FTIR not the\nXRD samples they are writing about. Proper reference or information is missing on any\nfabrication details!\nReply: We appreciate the reviewer’s suggestion on more comprehensive experimental details.\nWe\nclarify that the spin-coated films serve exclusively as a control to benchmark the evolution of the\nPbI -NMP solvate phase within the intermediate phase and the crystallinity of the annealing films\n2\n19\nrelative to the blade-coating process. To ensure a rigorous comparison, these reference films were\nfabricated using the exact same DMF/NMP (10:1) precursor formulation employed for the\nblade-coating process. We have updated these additional fabrication details in the Methods section\nand provided cross-referencing in the manuscript as follows:\nFabrication of inverted perovskite solar cell devices\nFabrication of perovskite solar cells by blade-coating\nThe pre-patterned ITO glass substrates…for current density-voltage (J-V) measurements.\nFabrication of perovskite solar cells by spin-coating\nThe perovskite precursor solution was prepared using the composition detailed previously,\ndissolved in a 10:1 (v/v) solvent mixture of DMF and NMP, and stirred overnight. The preparation\nof the NiO and Py3 based SAM layers follows the aforementioned procedures. The filtered\nX\nperovskite precursor solution was spin-coated onto the prepared substrate at 4000 rpm for 40\nseconds. During the spinning process, 150 µL of ethyl acetate (EA) was rapidly dispensed as an\nanti-solvent at the 20 s during the spinning step. Subsequently, the film was annealed at 130 °C for\n5 minutes. To complete the device, the remaining functional layers were then deposited using the\nmethodologies described above.\nMaterials characterization\nX-Ray Diffractometer (XRD)：To evaluate the diffraction intensity of the intermediate solvate\nphase and crystallinity of perovskite films, perovskite layers were deposited on NiOx/SAM\nsubstrates following the spin- and blade-coating protocols described above based on the exact\nsame DMF/NMP (10:1) precursor formulation. X-ray diffraction patterns were acquired upon\nantisolvent or gas quenching to capture the characteristic solvate peaks in the as-cast films and the\ncrystallinity of the annealing films. The signals were collected in reflection mode at room\ntemperature on a D8 advance diffractometer equipped with a 1D LynxEye detector using\nmonochromated Cu-Ka (λ = 1.5418 Å) radiation. Prior to XRD analysis, all samples were\npositioned at the same height, aligned with the edge of the holder’s top surface. The samples were\nsubjected to a spin rate of 10 r/min to ensure averaged results.\nLiquid chromatography-mass spectrometry (LC-MS): The NMP content in the perovskite wet\nfilms and annealed films was semi-quantified using an ultra-performance liquid chromatography\n(UPLC) system...\nThe Original phrase \"To evaluate the difference between blade-coating and spin-coating on the\ncrystallinity of perovskite films under identical precursor formulations and annealing conditions,\nwe performed X-ray diffraction (XRD) measurements (Fig. 1a). The perovskite films fabricated\nby spin-coating exhibited significantly higher diffraction intensities compared to those prepared\nby blade-coating.\" has been revised to \"To evaluate crystallinity differences, we benchmarked\nblade-coating films against spin-coating references prepared using identical precursor\nformulations and annealing conditions (see experimental details in Methods). X-ray diffraction\n(XRD) analysis reveals that the spin-coating films exhibit significantly higher diffraction\nintensities than their blade-coating counterparts (Fig. 1a).\"\n20\n5.The authors continue by writing \"In intermediate wet films\". This is a very unspecific term. A\nlot more information would help to understand how these films were made. Where are the\nroutines for producing theses intermediate films? For spin coating, does intermediate mean before or after\nthe antisolvent was applied? How do these films differ from the normal, complete fabrication?\nHow were the films transferred to the measurement equipment and how long did this take?\nAt\nwhich stage in the drying/morphology formation do the authors estimate the measurement to take\nplace? Can the authors do these measurements at different times to rule out the impact of time on\ntheir claims and data?\nReply: We thank the reviewer for the comments, which have helped us to clarify the specific\nprocessing windows defining our “intermediate wet films.” In this study, we define the\nintermediate wet film for spin-coating as the state immediately following antisolvent extraction\n(ethyl acetate) but strictly prior to thermal annealing. Similarly, for blade-coating, this denotes the\nfilm immediately post-gas quenching but preceding the thermal annealing. The fabrication of these\nintermediate wet films follows the identical protocol detailed in the Experimental Section for our\noperational devices, distinguished solely by the intentional omission of the final thermal annealing\nstep. All perovskite layers discussed were deposited onto identical NiOx/SAM substrates to\neliminate interface-induced variables.\nTo minimize environmental exposure and the time lag between fabrication and measurement, all\nintermediate samples were fabricated directly adjacent to the characterization equipment within\nthe diffractometer facility (Fig. R12a). The time interval between intermediate phase formation\n(via antisolvent or gas quenching) and the onset of X-ray data acquisition was commonly\nrestricted to under two minutes. Consequently, this protocol captures the film state at the precise\nonset of intermediate phase formation, before significant solvent volatilization.\nAddressing the concern regarding temporal instability during measurement, we performed a\nstability validation using sequential diffraction scanning. We subjected a fresh spin-coated\nintermediate film to three consecutive rapid scans targeting the characteristic PbI -NMP solvate\n2\npeak at 9.2°. As plotted in Fig. R12b and c, the normalized peak intensity remains virtually\nconstant across the measurement sequence. This kinetic stability confirms that the wet films exist\nin a quasi-stable state within our acquisition window, ensuring that the spectral differences\nreported in the manuscript stem from distinct processing kinetics rather than temporal\nmeasurement artifacts.\nFig. R12 a, Digital photograph of the Bruker D8 Advance diffractometer utilized for ex situ\ncharacterization. b, Three consecutive X-ray diffraction scans performed on a single spin-coated\n21\nintermediate wet film immediately following antisolvent quenching. c, Corresponding normalized\npeak intensities extracted from the sequential scans.\n6.The authors continue by writing \"Subsequently, we measured the NMP content in the\nintermediate phase wet films prepared by different methods using Liquid Chromatography-Mass\nSpectrometry (LC-MS, Fig. 1c, Supplementary Fig. 1). By fitting the peak area, we observed that\nthe NMP content in the blade-coating films was significantly higher than in the spin-coated ones\n(Supplementary Fig. 2a). This difference may arise from the prolonged solvent-precursor\ninteraction time in blade-coating.\" Although I really like the idea to measure the NMP content in\nthis way, I have several detailed questions, that I could not find\nanswered in the manuscript nor in\nthe supplementary. How did the authors extract the material to prepare it for LC-MS? Which\nsolvent did they use? What impact could this have? How did the authors make sure that the\ndifference in \"NMP content\" is not just due to a thicker, total film produced typically by blade\ncoating? What was the impact of the sample area and film thickness irregularity? I did not find any\nreference in the whole manuscript discussing film thicknesses. What is the measurement error of\nthe technique? How many films were measured and can the authors rule out statistical error of the\nmeasurements? In Figure 2a, the authors write \"spin coating\"\nand \"blade coating\". Was the\nspin-coated film already quenched or not? If it was quenched with antisolvent, it is no wonder that\nthere would be less NMP inside the film. Gas and antisolvent quenching would further not be\ncomparable in this case\nanyway, since the antisolvent would wash out most of the NMP and the present antisolvent changes the morphology\nformation completely. In Figure S2a, the\nmeasurement for \"blade-coating\" is at an value of about 3.5e3 a.u., while in Figure S2b the\n\"control\" datapoint is at 4.3e3 a.u., why are these not the same? How did the authors make sure that the\nfilms \"control\" and \"2OH\" had exactly the same time to dry before the measurement?\nHow did they make sure that both films\nhad the same thickness?\nReply: We thank the reviewer for the suggestion. We have expanded the Methods section to\ninclude precise sample preparation methods for liquid chromatography-mass spectrometry,\nensuring the complete validation and reproducibility of these critical measurements.\nSample Preparation Methods: To rigorously rule out geometric variations associated with film\nthickness, area, and morphological irregularity, we implemented a strict sampling protocol\nvisualized in Fig. R13a. A fixed film area (1.0 × 2.0 cm2) was precision-cut from the center of the\nwet film to avoid edge effects and fully dissolved in acetonitrile (ACN). The dissolved solid mass\nwas then quantified, and each sample was redissolved to a strict standard concentration of 1\nmg/mL prior to LC-MS injection. Consequently, the reported NMP values represent the specific\nsolvent content per unit mass of perovskite, not the total film burden. This normalization\nfundamentally decouples the measurement from geometric variations, ensuring a rigorous\ncomparison. In addition, we explicitly addressed the thickness concern via cross-sectional SEM\n(Fig. R13b). The images reveal that while the blade-coated films (703 nm) are indeed thicker than\nthe spin-coated references (592 nm), but our approach fundamentally eliminates the impact of film\nthickness.\nfixed film area (1.0 × 2.0 cm2) is dissolved in acetonitrile to ensure volumetric normalization. b,\nThe cross-sectional SEM images of annealed perovskite films prepared by spin-coating and\nblade-coating, showing thicknesses of approximately 592 nm and 703 nm, respectively. (Scale bar,\n1 μm).\nStatistical Robustness and Error Analysis: To rule out statistical error, we prepared six independent\nfilms for each condition (e.g., spin-coated, blade-coated, 2OH-modified), grouping them into three\ndistinct sets. Each set was measured independently (n=3). The data presented in Fig. R14\nrepresents the mean of these independent trials, with error bars denoting the standard deviation.\nThe instrument precision is verified with a relative standard deviation (RSD) below 5%,\nconfirming high reproducibility.\nFig. R14.a, Standard calibration curve for NMP quantification via LC-MS, establishing the linear\nbetween integrated signal intensity and NMP concentrations. b, The relative amount of NMP in\nintermediate wet films prepared using the DMF/NMP solvent system after spin-coating and\nblade-coating processes. c, Comparative NMP concentrations in blade-coated intermediate films\nprocessed from the 2Me/NMP system with and without additives (Control, 0OH, 1OH, 2OH)\nfollowing gas quenching. Error bars represent the standard deviation of three independent\nmeasurements (n=3).\nSpin-Coating vs. Blade-Coating Comparison: Regarding the comparison between\nantisolvent-quenched spin-coating (SC+AS) and gas-quenched blade-coating, we clarify that the\npurpose was to quantify the kinetic consequences of their respective standard protocols.\nSpin-coating relies on rapid antisolvent extraction, while blade-coating depends on slower\nevaporative gas quenching. The LC-MS data confirms that the scalable method inherently results\nin drastically higher solvent retention, validating the central problem statement of our work.\nClarification of Numerical Differences (Supplementary Fig. 2a vs. 2b): The variation in absolute\nNMP values between Supplementary Fig. 2a (blade-coating ~3.5×103 ng/mL) and 2b (control\n23\n~4.3×103 ng/mL) arises from the use of distinct solvent systems tailored to specific experimental\ngoals. For the kinetic comparison (Supplementary Fig. 2a/Fig. R14b), we employed the classical\nDMF/NMP system to establish a controlled baseline for comparing coating kinetics (spin vs.\nBlade coating). This choice was dictated by film quality constraints: while 2Me-based inks yield\npoor morphology via spin-coating, the DMF/NMP formulation produces high-efficiency films\n(PCE>25%) in both spin- and blade-coating regimes (under high-pressure gas quenching). This\nshared chemical baseline was strictly necessary to isolate the coating method as the sole variable.\nConversely, for the additive optimization (Supplementary Fig. 2b/Fig. R14c), we transitioned to\nthe 2-methoxyethanol (2Me)/NMP system as 2Me is the preferred host solvent for scalable\nfabrication using gas quenching. Validating our strategy within this specific matrix was essential\nto demonstrate its industrial applicability. The shift in solvent background alters the LC-MS\nionization baseline, resulting in the observed shift in absolute signal intensity.\nThe Control of Drying Time: To ensure temporal consistency, all samples were harvested, weighed,\nand dissolved immediately following the coating process. As detailed above, our\nmass-normalization method (1 mg/mL) renders any minor variations in drying time or film\nthickness irrelevant.\nWe have updated the LC-MS results in the manuscript and supplementary materials as follows:\nThe sentence “By fitting the peak area, we observed that the NMP content in the blade-coating\nfilms was significantly higher than in the spin-coated ones (Supplementary Fig. 2a).” has been\nrevised as “Quantitative LC–MS analysis reveals that blade-coated films retain substantially\nhigher NMP concentrations than their spin-coated counterparts processed from the identical\nprecursor (Supplementary Fig. 2a-b).\nIn addition, we have revised Supplementary Fig. 2 and Supplementary Fig. 16 to include the\nstandard deviation error bars. These updated results align perfectly with our original findings;\ntherefore, the discussion in the main text remains applicable without modification.\nSupplementary Fig. 2 a, Standard calibration curve for NMP quantification via LC–MS,\nestablishing the linear between integrated signal intensity and NMP concentrations. b, The relative\namount of NMP in intermediate wet films prepared using the DMF/NMP solvent system after\nspin-coating and blade-coating processes. c, Comparative NMP concentrations in blade-coated intermediate films\nwith and without 2OH during the gas quenching process. Error bars represent the standard\ndeviation of three independent measurements (n=3).\nprocessed from the 2Me/NMP system with and without additives (Control, 0OH, 1OH, 2OH)\nfollowing gas quenching. Error bars represent the standard deviation of three independent\nmeasurements (n=3).\n7.The authors write \"We fabricated devices with an ITO/SAM/PVK/C60/BCP/Ag structure and\nassessed their performance using additives with varying numbers of OH groups.\" They do not give\nany reference as to which SAM they are using and where the device fabrication is described. The\narchitecture written in these terms is very unspecific. There probably more than 10 choices for\nfilling \"SAM\". So, I had to search the manuscript to answer this question. In the part \"Fabrication\nof inverted perovskite solar cells devices\", the authors write \"Then the substrate was spin-coated\nwith a thin layer of NiOx nanoparticle film (20 mg/ml NiOx water solution) at 1500 rpm for 30 s,\nand annealed in ambient air at 125 °C for 10 min. 0.5 mg/ml Py3 in mixed solvent of methanol\nand DMF at a volume ratio 2:1 was deposited on the NiOx at 3000 rpm for 40 s. \"Not only was\nNiOx missing in the above described architecture. Furthermore, the NiOx nanoparticle solution is\nnot mentioned nor specified in the \"Materials\" part. The same is true for \"Py3\", which is\nmentioned only once in the manuscript and I estimate is 2-(pyren-1-yl)ethyl)phosphonic acid\nfrom https://www.nature.com/articles/s41586-024-07712-6. The missing attention on details\nshows that these are probably not the only inconsistencies and the reproduciblity of the results by\nother research groups is highly questionable.\nReply: We thank the reviewer for the suggestion in our experimental description. We have\nupdated these additional fabrication details in the manuscript as follows:\nThe sentence “We fabricated devices with an ITO/SAM/PVK/C60/BCP/Ag structure…” has been\nrevised to “We fabricated devices with an ITO/NiOx/2-(pyren-1-yl)ethyl) phosphonic acid (Py3)/\nCs FA PbI /LiF/C60/BCP/Ag structure…\n0.02 0.98 3\nMaterials\n... L-α-phosphatidylcholine (LP, purity 99%) was obtained from Shanghai Macklin Biochemical\nTechnology Co., Ltd. The NiOx nanoparticles (~10 nm diameter) were sourced from Advanced\nElection Technology. (2-(pyren-1-yl)ethyl) phosphonic acid (Py3) was synthesized following our\npreviously described (Nature,2024, 632, 8024, 301–306)...\n8.The authors write in the fabrication section \"The filtered perovskite precursor solution was then\nblade-coated on the substrate at 15 mm/s with the blade gap of 160 μm under dry air quenching.\"\nthey employed. The following questions should be answered specified: Where was the air quench\nsetup situated with respect to the coating: Distance from the coating and height above the sample\nWhat was the type model of air knife or nozzle geometry used: Slot-width and slot height?\nWhat\nwas the speed of the air exiting the nozzle? This can be described by working and static pressure\nvalues, or in the ideal case, by measuring the flow rate of air that comes through the nozzle.\nIf they\ndo not provide these parameters, the only way of ensuring reproduciblity is to share a sketch with\ndimensions and/or a photograph of their setup and share a video of their fabrication process. This\nis also be helpful to understand what they mean by \"wet\" or \"intermediate\" film.\nReply: We thank the reviewer for the suggestion, which is helpful to enhance the reproducibility\nof our experiments. We clarify that our gas-quenching setup utilizes standard laboratory\nequipment-specifically a high-speed blower (Laifen, LF03) or a handheld nitrogen gun, rather than\na calibrated industrial air knife. Consequently, precise fluid dynamic metrics such as nozzle slot\ngeometry or exit velocity are not applicable. To define the operational window, the blower was set\nto cold mode at maximum velocity, while the nitrogen gun operated at level 3 intensity with a 0.5\nMPa supply line pressure.\nAdopting the reviewer’s specific recommendation to ensure replicability in the absence of these\naerodynamic parameters, we have documented the exact physical configuration in Fig. R15 and\nprovided a real-time fabrication recording in Supplementary Video 3. This footage visually\ndefines the dynamic transition from the wet precursor state to the intermediate phase, offering an\nunambiguous reference for the film formation kinetics.\nFig. R15a, The photograph of blade-coating platform during precursor deposition. b, Snapshot of\nthe real-time gas-quenching process. The real-time precursor deposition and gas quenching are\nrecorded in Supplementary Video 3.\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows: “We fabricated devices with an ITO/.../Ag structure using the blade-coating\nconfiguration detailed in Supplementary Fig. 18 and Supplementary Video 3…\n9.The authors write:“Between each sub-cell, P1, P2, and P3 lines were laser-scribed (HANSPV PV-HL0303) to form the typical series-\nconnection of perovskite solar modules.”This is very spare\ninformation about how these lines were scribed. There is a lot of information about the laser\nscribing missing that would be necessary for reproducing these results. Further, there is not\ncharacterization of the scribing lines (optical, SEM micrsocopy,etc..), there is no characterization\nof the homogeneity of the module looking for hot spots and irregularities such as EL/PL\nmapping, LBIC or thermography. In a paper that has \"scalable\" in the title and discusses module\nfabrication, I would expect more information both on the scribing, which is not trivial, and on the estimation\nof scaling losses! See. e.g. https://onlinelibrary.wiley.com/doi/full/10.1002/pip.3489,\nhttps://advanced.onlinelibrary.wiley.com/doi/full/10.1002/aenm.202400115.\nReply: We appreciate the reviewer’s valuable suggestions, which are indeed critical for validating\nthe scalability and reproducibility of our fabrication process. As this critique overlaps with the\nscalability concerns raised in Point 3, we have presented the primary characterization data,\nincluding optical microscopy of the scribing lines, electroluminescence (EL) mapping, and\ninfrared thermography (IRT) in Fig. R13a-b of the preceding response. To specifically address the\nrequest for process transparency, we have updated the Methods section with the comprehensive\nlaser parameters for the P1, P2, and P3 steps, including wavelength, pulse frequency, and scan\nspeed. The optical micrograph in Fig. R13c confirms clean ablation channels with a total dead\nwidth of 280 µm, yielding a Geometric Fill Factor (GFF) of approximately 97%. Regarding\nspatial defects, the comparative EL and thermal imaging results discussed in Point 3\nunequivocally demonstrate that the 2OH-modified modules exhibit superior luminescence\nuniformity and effective suppression of localized hot spots compared to the control, validating the\nhigh quality of the scalable fabrication process.\n10.There are several other small details to correct: The 2-ME solution the authors employ is\nknown for degradation over time. The authors should make sure that non of the effects they\nobserve comes from degradation of the solution. They should provide the time between the\nexperiment and the preparation of the solution. The authors mention several times\nroom-temperature, but did not specify exactly at which temperature they operate at.\nReply: We thank the reviewer for the question. To mitigate stability concerns associated with\n2-methoxyethanol (2-ME), we enforced a strict 1.5-hour utilization window for precursor\nsolutions to ensure experimental reproducibility. To empirically verify that solution aging did not\nartifactually influence our results, we tracked the photovoltaic performance of devices fabricated\nfrom inks aged over this specific interval (0, 0.5, 1.0, and 1.5 h). As presented in Fig. R16, the\nstatistical distributions of PCE and associated metrics exhibit negligible variation across the\ntesting period, confirming that the solution remains chemically stable within our processing\ntimeframe. Consequently, the observed performance trends are intrinsic to the proposed additive\nstrategy rather than precursor degradation. Regarding environmental specifications, we have\nupdated the Methods section to define \"room temperature\" as a controlled environment of 25 ±\n1 °C.\nDistributions of a, PCE, b, FF, c, V and d, J for devices fabricated using\nOC SC\n2-methoxyethanol-based inks stored for varying intervals (0, 0.5, 1.0, and 1.5 h) prior to\nblade-coating.\n11.Grammar and Spell check: In the above example \"employing the hydroxyl-terminated\nmolecular that ooutcompetes NMP\". you find a typo and \"molecular\" instead of \"molecule\".\nPlease run a spell and grammar checker over your manuscript.\nReply: We sincerely thank the reviewer for the careful evaluation of our manuscript and pointing\nout these editorial issues. We have conducted a comprehensive linguistic review of the entire\nmanuscript to eliminate typographical and grammatical errors.\nThe specific corrections have been implemented in the revised manuscript as follows:\nThe Original phrase \"...employing the hydroxyl-terminated molecular that ooutcompetes NMP”\nhas been corrected to \"…employing the hydroxyl-terminated molecule bis (2-hydroxyethyl)\ndimethylammonium chloride (2OH)that outcompetes NMP...\nThe sentence“CFM maps reveal revealed an increase…”has been corrected to“CFM maps\nrevealed an increase…”\nThe phrase \"This inherent dichotomy... translate into distinct crystallization process...\"has been\ncorrected to \"This inherent dichotomy... translates into distinct crystallization processes...\n28\n12.In Figure 4f, the authors show Normalized PCE. They must show absolute PCE instead, since\nrelative PCE can be misleading.\nReply: We appreciate the reviewer’s valid point regarding the presentation of stability data.\nWe\nhave revised Figure 4f to plot absolute efficiency values under continuous maximum power point\n(MPP) tracking at ~50 °C (Fig. R17). This direct visualization confirms that the stability\nenhancement is intrinsic. The 2OH-modulated devices not only initiate with higher efficiency but\nsustain a superior performance trajectory throughout the 900 hours test, retaining 92.6% of their\ninitial value compared to 80.8% for the control.\nFig. R17 MPP tracking of perovskite devices fabricated with and without 2OH under continuous\none-sun light soaking at ~50 °C.\nWe have modified the manuscript as follows:\n“Furthermore, statistical analysis of ten mini-modules (20.8 cm2) substantiates scalability, where\n2OH-modified devices achieve 22.6 ± 0.8% efficiency versus the 20.9 ± 1.0% for control\n(Supplementary Fig. 27). The champion PCE of modules was improved from 21.5% to 22.9% (Fig.\n4d and Supplementary Table 5). We next translated the strategy to a pre‑pilot sub‑module\n(30 × 30 cm², an aperture area of 728.0 cm²), which yielded a PCE of 22.9% under reverse scan\nand 21.9% under forward scan (Fig. 4e and Supplementary Table 6). A record certified PCE of\n22.58% was also achieved (Supplementary Fig. 28), demonstrating the suitability of this strategy\nfor commercial‑scale production.\nthe steady-state power output (SPO) (b) of perovskite solar cell devices fabricated with and\nwithout 2OH. The inset shows the detailed photovoltaic parameters. c, PCE distribution of\nperovskite solar cells with and without 2OH. d, I–V curves of the champion perovskite\nmini-modules (aperture area: 20.8 cm²) for control and 2OH treated devices. Inset, a photograph\nof the mini-module. e, I–V curves of the champion 30 cm × 30 cm sub-module (aperture area:\n728.0 cm²) with 52 series-connected subcells under reverse and forward scans. Inset, a photograph\nof a 30 cm × 30 cm sub-module. f, MPP tracking of perovskite devices fabricated with and without\n2OH under continuous one-sun light soaking at ~50 °C.\nSupplementary Table 5. Photovoltaic parameters of the control and 2OH treated perovskite\nmini-modules (20.8 cm2).\nV I FF PCE\nOC SC\nSample\n(V) (mA) (%) (%)\nControl 11.44 52.4 74.7 21.5\n2OH 11.61 52.2 78.5 22.9\nSupplementary Table 6. Photovoltaic parameters of forward and reverse scan I-V curves of\nsub-modules (728.0 cm2) with 2OH.\nV I FF PCE\nOC SC\nSample\n(V) (A) (%) (%)\nForward 59.13 0.35 77.0 21.9\nReverse 59.77 0.35 79.3 22.9\nReviewer #3:\nThis article makes a significant contribution to perovskite photovoltaics by identifying τ as a\nint\ncritical parameter and demonstrating that coordination competition enables high-performance\nlinear printed devices. The authors identify a previously overlooked kinetic parameter governing\nfilm quality in blade-coating processes and propose a coordination competition strategy using\nbis(2-hydroxyethyl) dimethylammonium chloride (2OH) to address this challenge. The material\ncharacterization is sound, especially FTIR and crystallography studies, though statistical rigor for\nlarge-area devices can add value to a certain extent. The work's practical impact and mechanistic\ninsights make it suitable for high-impact publication following the recommended revisions. The\nefficiency of 26.5% is rather impressive with blade-coated devices, but an independent\ncertification is beneficial to demonstrate the state-of-the-art performance of the blade-coated\ndevice, especially considering the impact of the journal here. I have a few major queries from the\nscientific front before recommending the manuscript for publication in Nature Communications.\nReply: We are sincerely grateful to the reviewer for the support towards the potential publication\nof our manuscript. We have carefully considered all the comments and suggestions from the\nreviewer and revised our manuscript accordingly.\n1. The efficiency of 26.5% is rather impressive with blade-coated devices, but an independent\ncertification is beneficial to demonstrate the state-of-the-art performance of the blade-coated\ndevice, especially considering the impact of the journal here.\nindustrial relevance of this blade-coating strategy, we commissioned independent third-party\ncertification for a large-area module (300 mm × 300 mm) by Sinores Lab (CNAS/CMA\naccredited). As shown in Fig. R18, the certified PCE measured under reverse scan reached 22.58%\nover an effective area of 728.0 cm2, marking the highest certified efficiency for perovskite\nsub-modules reported to date. Achieving such metrics on module-scale substrates verifies the\nexceptional film uniformity and transferability of our coordinate competition protocol.\n1. The authors made a few typos, namely “hydroxyl-terminated molecular that ooutcompetes\nNMP”, which should be “hydroxyl-terminated molecule that outcompetes”. Additionally, it would\nbe beneficial to introduce the molecule in this introductory paragraph, explicitly stating its\nchemical name at the very least.\nReply: We thank the reviewer for the valuable suggestions. We have rectified the specified\ntypographical errors and explicitly integrated the full chemical identity of the additive into the\nintroducion to establish immediate clarity. We have incorporated these corrections into the revised\nmanuscript as follows: To overcome this bottleneck, we devise a dynamic coordination\ncompetition strategy employing the hydroxyl-terminated molecule bis (2-hydroxyethyl)\ndimethylammonium chloride (2OH)that outcompetes NMP...\nFig. R18 Certification report of the 30×30 cm2 submodule.\n2. Do PACl and MACl impact the crystallization rate by controlling the intermediate adducts?\nCould the authors clarify the role of such high mol% additives alongside 2OH molecule? What\nhappens in the absence of PACl or MACl but in the presence of 2OH? Do you expect them to\nbehave similar to 0OH molecule used in the study?\nReply: We thank the reviewer for the questions. The reviewer correctly surmises that PACl and\nMACl govern the crystallization rate through intermediate adduct formation. These\nalkylammonium chlorides form transient RA···H-Cl-PbI intermediates that lower the\n2\nthermodynamic barrier for the δ→α phase transition. Their subsequent deprotonation and\nvolatilization directly afford the kinetic window for grain growth and orientation adjustment\n(Nature, 2023, 616, 7958, 724-730).\nAs shown in Fig. R19, our statistical data confirms this primary role: the introduction of MACl\nalone (Ref vs. MA) induces a discrete efficiency jump from ~21% to ~25%, establishing it as the\nessential driver for high-quality α-FAPbI formation and the fundamental baseline for device\n3\nperformance. Similarly, PACl (Ref vs. PA) acts as an auxiliary modulator, significantly enhancing\nOC\noptimization, but exhibits limited intrinsic regulation capability in isolation, requiring MACl to\nmaintain high current density.\nIn contrast, the 2OH molecule operates through a different mechanism: coordination competition.\nRather than driving the phase transition itself, 2OH competitively coordinates with Pb2+ to\ndisplace NMP, thereby suppressing the formation of overly stable solvent-solute adducts that\nimpede pure α phase formation (Nature, 2024, 628, 8007, 299-305; ACS Energy Letters, 2024, 9,\n7, 3418-3425.) This effect is synergistic with the chloride additives. Across all conditions (Ref, PA,\nMA, and MA/PA), the addition of 2OH consistently improves FF and V . Specifically, in the\nOC\noptimized MA/PA system, 2OH further accelerates the α-phase transformation and enhances film\ncrystallinity and phase purity.\nIn the absence of these chloride drivers, the system lacks the thermodynamic impetus to form the\nα-phase. Comparing the reference (Ref) to the 2OH-only condition (2OH), we observe only\nmarginal gains in efficiency (~21.2% to ~21.8%). This confirms that 2OH cannot independently\ndrive nucleation and crystal growth or substitute for the chlorides. It behaves fundamentally\ndifferently from the inert 0OH control, which lacks both the crystallization drive of chlorides and\nthe coordination capability of hydroxyls. Thus, 2OH acts as a critical α-phase purity enhancer that\ncomplements, rather than replaces, the foundational crystallization kinetics established by PACl\nand MACl.\nFig. R19 Statistical performance distributions of a, PCE, b, V , c, FF, and d, J for perovskite\nOC SC\nsolar cells fabricated with distinct additive compositions. The specific impact of the\nhydroxyl-terminated molecule in the absence of crystallization-modulating chlorides is isolated in\nthe ‘2OH’ condition, serving as a baseline to contrast with its synergistic incorporation into the\nbinary (‘PA/2OH’, ‘MA/2OH’) and ternary (‘MA/PA/2OH’) co-additive systems. Ref,\nadditive-free control; PA, propylammonium chloride; MA, methylammonium chloride.\n33\n3. The authors should demonstrate the difference in concentration 2OH group (PbI -2OH-NMP)\n2\nand its impact on C=O stretching vibration peaks by showing the peak-shift evolution with\ndifferent concentrations of 2OH. The concentration of 2OH in relation to other compounds used\nfor FTIR measurements should also be mention in detail.\nReply: We thank the reviewer for the suggestion to elucidate the concentration-dependent\ninteraction mechanism. To map the specific role of the 2OH additive, we performed a systematic\nFTIR study tracking the C=O stretching vibration (ʋ ) of NMP across a broad range of\nC=O\nPbI :2OH molar ratios (500:1 to 5:1), as detailed in Fig. R20 and Table R1. Pure NMP and the\nIn the low-concentration regime (500:1 to 100:1), the introduction of trace 2OH induces a\ncompetitive displacement of NMP due to the superior binding affinity of the hydroxyl group for\nPb2+. This results in two distinct carbonyl populations. First, a \"quasi-free\" NMP signal emerges at\n1683-1687 cm⁻¹. We attribute the redshift relative to pure NMP (1693 cm⁻¹) not to hydrogen\nbonding, but to the solvation shell effect exerted by the high ionic strength environment, which\nperturbs the solvent vibrational modes. As the 2OH concentration increases, this perturbation\ndiminishes, and the frequency shifts back toward the intrinsic bulk value. Second, the coordinated\nNMP peak exhibits a progressive blueshift (~1630 → 1634 cm⁻¹), indicative of a weakening\nPb···O=C interaction. In the high-concentration regime (50:1 to 5:1), the chemical environment\nevolves further, resolving into three distinct states. The \"free\" NMP signal stabilizes at 1692-1694\ncm⁻¹, confirming the substantial displacement of solvent by 2OH molecule. A \"weakly\ncoordinated\" population appears at 1640-1643 cm⁻¹, corresponding to NMP bound to the modified\n[PbIₓ(OH)ᵧ] complex. Crucially, a new feature emerges at 1613 cm⁻¹. We assign this to a strong\nhydrogen-bonding interaction (Pb-O-H···O=C). Coordination of the hydroxyl oxygen to the Pb2+\ncenter induces severe polarization of the O–H bond, dramatically enhancing its protic acidity. This\nestablishes a robust hydrogen bond with the NMP carbonyl, exhibiting an interaction energetically\nsuperior to the original direct metal-solvent coordination.\nFig. R20 Evolution of FTIR spectra focusing on the C=O stretching vibration (ʋ ) of NMP\nC=O\nwithin the PbI -NMP system at varying PbI :2OH molar ratios ranging from 500:1 to 5:1.\n2 2\nC=O\nacross varying PbI -2OH molar ratios.\nRatio (\"Free NMP\") (\"Coordinated (\"H-bonded\n(PbI₂:2OH) (cm⁻¹) NMP\") NMP\")\n(cm⁻¹) (cm⁻¹)\nPure NMP 1693 / /\nPbI₂-NMP / 1625 /\n500:1 1683 1630 /\n200:1 1689 1631 /\n100:1 1687 1634 /\n50:1 1692 1640 1613\n20:1 1692 1640 1613\n10:1 1694 1641 1613\n5:1 1694 1641 1613\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows:\n“Tracking ʋ evolution across PbI :2OH ratios (500:1-5:1) reveals a concentration-dependent\nC=O 2\ncoordination shift (Supplementary Fig. 8 and Table S1). The additive competitively displaces\nNMP, progressively weakening the Pb···O=C interaction to restore the free solvent population.\nNotably, a distinct feature emerges at 1613 cm-1 in the high-concentration regime, attributable to\nrobust hydrogen bonding (Pb-O-H···O=C) driven by the polarization-enhanced acidity of the\ncoordinated hydroxyl group.\nSupplementary Fig. 8 Evolution of FTIR spectra focusing on the C=O stretching vibration (ʋ )\nC=O\nof NMP within the PbI -NMP system at varying PbI :2OH molar ratios ranging from 500:1 to 5:1.\n2 2\nC=O\nand peak\nassignments across varying PbI -2OH molar ratios.\nRatio (\"Free (\"Coordinated (\"H-bonded\n(PbI₂:2OH) NMP\") NMP\") NMP\")\n(cm⁻¹) (cm⁻¹) (cm⁻¹)\nPure NMP 1693 / /\nPbI₂-NMP / 1625 /\n500:1 1683 1630 /\n200:1 1689 1631 /\n100:1 1687 1634 /\n50:1 1692 1640 1613\n20:1 1692 1640 1613\n10:1 1694 1641 1613\n5:1 1694 1641 1613\n4. Why does 0OH molecules increase NMP retention in LC-MS analysis in Fig. S11. Does PACl\nand MACl have a similar effect?\nReply: The anomalous retention of NMP induced by 0OH stems from its chemical inertness\nrelative to the coordination environment. Lacking the active hydroxyl moiety, 0OH is incapable of\ncompetitively displacing NMP ligands similar to 2OH. Instead, it likely stabilizes the PbI -NMP\n2\nsolvate structure through steric confinement or electrostatic interactions, effectively obstructing\nsolvent volatilization channels. This results in the observed counterintuitive increase in residual\nsolvent. This behavior stands in stark contrast to that of PACl and MACl. These chlorides function\nas the essential driver for high-quality α-FAPbI formation. As detailed in Point 2, they operate by\n3\nforming RA···H-Cl-PbI intermediates that lower the thermodynamic barrier for the δ→α phase\n2\ntransition. Crucially, their mechanism involves the deprotonation and subsequent volatilization, a\nprocess that promotes nucleation and crystal growth. Consequently, while 0OH exacerbates\nsolvent trapping, PACl and MACl actively engineer the crystallization kinetics to construct\nhigh-quality perovskite films, representing fundamentally opposing mechanisms regarding film\nevolution.\n5. Can 2OH completely replace NMP completely? Can the authors shed some insights into this\nprocess?\nReply: We experimentally evaluated the feasibility of complete NMP substitution. As presented in\nFig. R21, devices fabricated from NMP-free precursor inks exhibit a catastrophic drop in\nefficiency to 5.42%, confirming that 2OH cannot function as a standalone replacement for the\ncoordinating solvent.\nThis failure stems from the distinct different physical and chemical roles of the two molecules. In\nblade-coated formulations, the solvent system is typically necessitate a binary solvent architecture\n36\ncomprising a volatile non-coordinating component (e.g., 2-ME) and a lower-volatility\ncoordinating agent (e.g., NMP) (Science Advances, 2019, 5, 12, eaax7537). As a potent Lewis\nbase with a high donor number, NMP forms intermediate phase that retard reaction kinetics\nbetween PbI with FAI, thereby regulating crystallization before being removed via volatilization\n2\nduring gas quenching and annealing. In contrast, 2OH is a non-volatile solid. Attempting a\nstoichiometric substitution introduces a massive burden of insulating organic material that remains\ntrapped within the matrix. This residual mass inevitably induces secondary phase formation and\nimpedes charge transport, directly resulting in the poor performance observed in the NMP-free\ndevices.\nHigh-quality film formation of blade-coating relies on a precise kinetic equilibrium between rapid\nnucleation, driven by the evaporation of the volatile host (2-ME), and retarded crystal growth\nregulated by the coordinating agent (NMP). NMP acts as a critical kinetic buffer, counteracting the\nflash evaporation of 2-ME to prevent premature supersaturation and ensuring adequate substrate\nwetting. Through the formation of solvated intermediates, it can extend the processing window for\nmeniscus-guided blade coating and regulate the crystallization rate. As a solid additive, 2OH lacks\nthe vapor pressure dynamics requisite for regulating wet-film drying rates. Consequently,\nremoving NMP eliminates this solvent-phase buffer, precipitating uncontrolled, rapid nucleation\nand inferior grain morphology.\nCrucially, NMP governs the precursor colloidal network and rheological parameters required for\nthe blade-coating process window. Its strong coordination modulates viscosity and surface tension\nto accommodate meniscus-guided deposition, ensuring macroscopic homogeneity. Substituting\nthis liquid regulator with high-concentration solid 2OH destabilizes the ink rheology, shifting fluid\nproperties outside the optimal processing regime and inevitably compromising both film\nuniformity and crystalline quality.\nTherefore, NMP functions as an essential dual-purpose regulator, defining precursor rheology\nwhile balancing nucleation and growth kinetics through its volatile coordination. 2OH, by contrast,\noperates strictly as a solid-state modulator to refine phase purity through coordination competition.\nAttempting to substitute the coordination solvent with this additive incurs severe thermodynamic\npenalties, yielding impurity phases and a total loss of kinetic control that precludes\nhigh-performance device fabrication.\nFig. R21 Current density–voltage (J-V) characteristic of a perovskite device fabricated from a\nprecursor ink excluding NMP solvent. The inset table summarizes the corresponding photovoltaic\nparameters.\n37\n6. The authors should mention concentrations of 0OH, 1OH and 2OH used for statistics in Fig\nS13.\nReply: We appreciate the reviewer’s suggestion to explicitly define the experimental parameters.\nWe have specified the fixed concentration of 0.3 mol% for the 0OH, 1OH, and 2OH additives in\nthe revised manuscript to ensure methodological clarity. Note that the original Supplementary Fig.\n13 has been renumbered to Supplementary Fig. 19 in the revised version due to the inclusion of\nadditional data. Accordingly, the figure caption has been updated as follows:\nSupplementary Fig. 19Statistical distributions of photovoltaic parameters for control devices and\nthose treated with 0OH, 1OH, and 2OH additives at a fixed concentration of 0.3 mol%. a, PCE, b,\nV , c, FF, and d,J .\nOC SC\n7.The authors should display the statistics obtained for large-area devices with and without\ncontrol. This is important to understand the true potential of the additive.\nReply: We appreciate the suggestion to validate the scalability of our approach through statistical\nanalysis. To address this, we fabricated large-area perovskite mini-modules (aperture area: 20.8\ncm²) under both control and 2OH-modified conditions. The statistical distribution of photovoltaic\nmetrics across 10 independent modules is presented in Fig. R22. The 2OH-modified modules\nexhibit a marked performance enhancement, achieving an average PCE of 22.6 ± 0.8%, compared\n20.9 ± 1.0% for the control. The most significant gain appears in the FF, which increases from\napproximately 74% to 78%. This substantial improvement, coupled with a consistently elevated\nV , confirms that the coordination competition strategy effectively minimizes non-radiative\nOC\nrecombination losses across the expanded active area, demonstrating high reliability and\nreproducibility for scalable fabrication.\nFig. R22 Statistical distributions of performance parameters for large-area control and\n2OH-modified perovskite modules.\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows:\n“Furthermore, statistical analysis of ten mini-modules (20.8 cm2) substantiates scalability, where\n2OH-modified devices achieve 22.6 ± 0.8% efficiency versus the 20.9 ± 1.0% for control\n(Supplementary Fig. 20).\nand 2OH-modified perovskite modules (20.8 cm2).\n8.Finally, please make a comparison table comparing the performance of particular bandgap\nblade-coated devices with the literature, so the reader could get a sense of state-of-the-art devices.\nReply: We thank the reviewer’s suggestion to benchmark our performance against the literature.\nAs requested, we tabulated scalable blade-coated small-area devices exceeding 25% efficiency\nreported over the past five years (Table R2). Expanding this analysis to large-area fabrication,\nTable R3 surveys blade- and slot-die-coated mini-modules (20-200 cm², PCE > 21%) and\nsub-modules (200–800 cm²). As visualized in Fig. R23, our devices achieving 26.5% (small-area),\n22.9% (mini-module, 20.8 cm2), and 22.9% (sub-module, 728.0 cm2) occupy a leading position\nwithin the current technological landscape. This achievement underscores the efficacy of our\nstrategy but also the practical potential for scalable manufacturing.\nTable R2 A summary of previously reported efficiencies exceeding 25% fabricated via scalable\nblade-coating methods for small perovskite devices reported in the past five years.\nFilm\nDevice Area PCE\nfabrication Ref.\nStructure （cm2） (%)\nmethod\nBlade coating Advanced Materials, 2024, 36,\np-i-n N/A 25.1\n(air-knife) 52, 2412059.\nBlade coating\nn-i-p 0.09 25.31 Joule, 2024, 8, 9, 2539-2553.\n(air-knife)\nBlade coating Advanced Functional Materials,\np-i-n 0.079 25.01\n(vacuum) 2025, 2506386.\nBlade coating Nature Synthesis, 2025, 4, 2,\nn-i-p 0.09 25.9\n(shear force) 196-208.\nBlade coating Advanced Energy Materials,\nn-i-p 0.076 25.75\n(air-knife) 2025, 15, 32,2501227.\nBlade coating\nn-i-p N/A 26.11 Joule, 2025, 9, 5,101919.\n(air-knife)\nBlade coating Advanced Functional Materials,\np-i-n 0.079 25.01\n(vacuum) 2025, 35, 39, 2506386.\np-i-n 0.08 26.0\n(air-knife) eadu3493.\nBlade coating Advanced Energy Materials,\np-i-n N/A 25.91\n(air-knife) 2025, 15, 35, 2502000.\nBlade coating DOI:10.1016/j.joule.2025.102212\np-i-n 0.049 26.0\n(air-knife) (In press)\nBlade coating Energy & Environmental Science,\np-i-n 0.058 25.2\n(air-knife) 2025, 18, 20, 9149-9157.\nBlade coating Energy & Environmental Science,\np-i-n 0.09 25.38\n(vacuum) 2025, 18, 9917-9926\nBlade coating Advanced Functional Materials,\np-i-n 0.035 25.43\n(air-knife) 2025, e23243.\nBlade coating Advanced Energy Materials,\np-i-n 0.09 25.52\n(vacuum) 2025, 15, 40, e02193.\nBlade coating Advanced Materials, 2025, 37,\np-i-n 0.09 25.8\n(air-knife) 43, e06291.\nBlade coating Advanced Energy Materials,\np-i-n N/A 25.91\n(vacuum) 2025, 15, 35, 2502000.\nBlade coating\np-i-n 0.0665 26.5 This work\n(air-knife)\nTable R3 A summary of reported efficiencies for scalable blade- and slot-die-coated mini-modules\n(20–200 cm², PCE > 21%) and sub-modules (200–800 cm²) in the past five years.\nFilm\nDevice Area\nPCE (%) fabrication Ref.\nStructure （cm2）\nmethod\nMini-Modules (20-200 cm2)\nBlade coating\nn-i-p 31 21.23 Joule, 2023, 7, 4, 797-809.\n(air-knife)\nBlade coating\nn-i-p 31 21.23 Joule, 2023, 7, 4, 797-809.\n(air-knife)\nBlade coating Science,2023, 380, 6647,\np-i-n 26.9 21.8\n(air-knife) 823-829.\nBlade coating Advanced Materials, 2024, 36,\np-i-n 30.03 22.0\n(air-knife) 52, 2412059.\nBlade coating Nature, 2024, 628, 8007,\nn-i-p 27.22 22.0\n(vacuum) 299-305.\nBlade coating Nature Synthesis, 2025, 4, 2,\nn-i-p 70 21.78\n(shear force) 196-208.\nBlade coating Advanced Energy Materials,\nn-i-p 22.9 23.50\n(air-knife) 2025, 15, 32,2501227.\nn-i-p 57.20 22.76 Joule, 2025, 9, 5,101919.\n(air-knife)\nSlot-die coating Nature Communications,2025,\np-i-n 56.5 21.5\n(vacuum) 16, 1, 2052.\nBlade coating Science Advances, 2025, 11, 3,\nn-i-p 56 22.05\n(vacuum) eadp3112.\nSlot-die coating Advanced Energy Materials,\np-i-n 164 22.05\n(air-knife) 2025, 15, 35, 2502000.\nBlade coating DOI:10.1016/j.joule.2025.102212\np-i-n 20.25 22.5\n(air-knife) (In press)\n23.25 22.80 Slot-die coating Nature Communications, 2025,\np-i-n\n87.45 21.45 (vacuum) 16, 1, 9110.\nBlade coating Energy & Environmental Science,\np-i-n 21.84 23.22\n(vacuum) 2025, 18, 9917-9926\nBlade coating Advanced Energy Materials,\np-i-n 164 22.05\n(vacuum) 2025, 15, 35, 2502000.\nBlade coating\np-i-n 20.8 22.9 This work\n(air-knife)\nSub Modules (200-800 cm2)\nBlade coating Nature Energy, 2022, 7, 6,\nn-i-p 205 15.3\n(air-knife) 528-536.\nSlot-die coating Nature, 2024, 634, 8036,\nn-i-p 715.1 22.80\n(vacuum) 1091-1095.\nBlade coating Advanced Energy Materials,\nn-i-p 214.7 19.0\n(air-knife) 2024, 14, 25, 2400791.\nSlot-die coating Nature Energy, 2024, 9, 12,\nn-i-p 310 18.90\n(air-knife) 1540-1550.\n802 17.59 Blade coating DOI:10.1016/j.joule.2025.102212\np-i-n\n804 20.2 (air-knife) (In press)\nSlot-die coating Nature Communications,2025,\np-i-n 749.276 20.21\n(vacuum) 16, 1, 9110.\nSlot-die\np-i-n 728.0 22.9 coating This work\n(air-knife)\nperovskite solar cells, in comparison to the efficiency of the champion perovskite devices in this\nwork. b, A summary of previously reported efficiencies of scalable-coated perovskite solar\nmini-modules with an aperture area of 20 to 200 cm2 and sub-module from 200 to 800 cm2, in\ncomparison to the efficiency of the champion modules reported in this work.\nWe have added these additional results and discussions in the manuscript and supplementary\nmaterials as follows:\n“A statistical summary of efficiencies versus active area across scalable fabrication methods is\npresented in Supplementary Fig. 29 (Supplementary Tables 7, 8). Our method achieved champion\nPCEs of 26.5% for small-area cells, 22.9% for mini-modules, and 22.9% for sub-modules,\nsurpassing state-of-the-art benchmarks for blade- and slot-die coating. These results reveal the\nefficacy of our strategy for scalable manufacturing.\nSupplementary Table 7. A summary of previously reported efficiencies exceeding 25%\nfabricated via scalable blade-coating methods for small perovskite devices reported in the past five\nyears.\nBlade coating Advanced Materials, 2024, 36,\np-i-n N/A 25.1\n(air-knife) 52, 2412059.\nBlade coating\nn-i-p 0.09 25.31 Joule, 2024, 8, 9, 2539-2553.\n(air-knife)\nBlade coating Advanced Functional Materials,\np-i-n 0.079 25.01\n(vacuum) 2025, 2506386.\nBlade coating Nature Synthesis, 2025, 4, 2,\nn-i-p 0.09 25.9\n(shear force) 196-208.\nBlade coating Advanced Energy Materials,\nn-i-p 0.076 25.75\n(air-knife) 2025, 15, 32,2501227.\nBlade coating\nn-i-p N/A 26.11 Joule, 2025, 9, 5,101919.\n(air-knife)\nBlade coating Advanced Functional Materials,\np-i-n 0.079 25.01\n(vacuum) 2025, 35, 39, 2506386.\np-i-n 0.08 26.0\n(air-knife) eadu3493.\nBlade coating Advanced Energy Materials,\np-i-n N/A 25.91\n(air-knife) 2025, 15, 35, 2502000.\nBlade coating DOI:10.1016/j.joule.2025.102212\np-i-n 0.049 26.0\n(air-knife) (In press)\nBlade coating Energy & Environmental Science,\np-i-n 0.058 25.2\n(air-knife) 2025, 18, 20, 9149-9157.\nBlade coating Energy & Environmental Science,\np-i-n 0.09 25.38\n(vacuum) 2025, 18, 9917-9926\nBlade coating Advanced Functional Materials,\np-i-n 0.035 25.43\n(air-knife) 2025, e23243.\nBlade coating Advanced Energy Materials,\np-i-n 0.09 25.52\n(vacuum) 2025, 15, 40, e02193.\nBlade coating Advanced Materials, 2025, 37,\np-i-n 0.09 25.8\n(air-knife) 43, e06291.\nBlade coating Advanced Energy Materials,\np-i-n N/A 25.91\n(vacuum) 2025, 15, 35, 2502000.\nBlade coating\np-i-n 0.0665 26.5 This work\n(air-knife)\nSupplementary Table 8. A summary of reported efficiencies for scalable blade- and\nslot-die-coated mini-modules (20–200 cm², PCE > 21%) and sub-modules (200–800 cm²) in the\npast five years.\nDevice Area PCE Film fabrication\nRef.\nStructure （cm2） (%) method\nMini-Modules (20-200 cm2)\nBlade coating\nn-i-p 31 21.23 Joule, 2023, 7, 4, 797-809.\n(air-knife)\nBlade coating Science,2023, 380, 6647,\np-i-p 26.9 21.8\n(air-knife) 823-829.\nBlade coating Advanced Materials, 2024, 36,\np-i-n 30.03 22.0\n(air-knife) 52, 2412059.\nBlade coating Nature, 2024, 628, 8007,\nn-i-p 27.22 22.0\n(vacuum) 299-305.\nBlade coating Nature Synthesis, 2025, 4, 2,\nn-i-p 70 21.78\n(shear force) 196-208.\nBlade coating Advanced Energy Materials,\nn-i-p 22.9 23.50\n(air-knife) 2025, 15, 32,2501227.\nn-i-p 57.20 22.76 Joule, 2025, 9, 5,101919.\n(air-knife)\nSlot-die coating Nature Communications,2025,\np-i-n 56.5 21.5\n(vacuum) 16, 1, 2052.\nBlade coating Science Advances, 2025, 11, 3,\nn-i-p 56 22.05\n(vacuum) eadp3112.\nSlot-die coating Advanced Energy Materials,\np-i-n 164 22.05\n(air-knife) 2025, 15, 35, 2502000.\nBlade coating DOI:10.1016/j.joule.2025.102212\np-i-n 20.25 22.5\n(air-knife) (In press)\n23.25 22.80 Slot-die coating Nature Communications, 2025,\np-i-n\n87.45 21.45 (vacuum) 16, 1, 9110.\nBlade coating Energy & Environmental Science,\np-i-n 21.84 23.22\n(vacuum) 2025, 18, 9917-9926\nBlade coating Advanced Energy Materials,\np-i-n 164 22.05\n(vacuum) 2025, 15, 35, 2502000.\nBlade coating\np-i-n 20.8 22.9 This work\n(air-knife)\nSub Modules (200-800 cm2)\nBlade coating Nature Energy, 2022, 7, 6,\nn-i-p 205 15.3\n(air-knife) 528-536.\nSlot-die coating Nature, 2024, 634, 8036,\nn-i-p 715.1 22.80\n(vacuum) 1091-1095.\nBlade coating Advanced Energy Materials,\nn-i-p 214.7 19.0\n(air-knife) 2024, 14, 25, 2400791.\nSlot-die coating Nature Energy, 2024, 9, 12,\nn-i-p 310 18.90\n(air-knife) 1540-1550.\n802 17.59 Blade coating DOI:10.1016/j.joule.2025.102212\np-i-n\n804 20.2 (air-knife) (In press)\nSlot-die coating Nature Communications, 2025,\np-i-n 749.276 20.21\n(vacuum) 16, 1, 9110.\nSlot-die\np-i-n 728.0 22.9 coating This work\n(air-knife)\nsmall-area perovskite solar cells, in comparison to the efficiency of the champion perovskite\ndevices in this work. b, A summary of previously reported efficiencies of scalable-coated\nperovskite solar mini-modules with an aperture area of 20 to 200 cm2 and sub-module from 200 to\n800 cm2, in comparison to the efficiency of the champion modules reported in this work.\n(Manuscript# NCOMMS-25-68139)\nWe are gratified that all reviewers are satisfied with our revisions and recommend the manuscript\nfor publication in Nature Communications. We have carefully implemented the final minor\nsuggestions from Reviewer 2 to further enhance the clarity of our work. Detailed point-by-point\nreplies to the reviews along with the changes we have made in the manuscript and Supplementary\nInformation are provided below.\n(Notes: For the convenience of the reviewers, at the end of each piece of reply, we quoted the\nfigures and texts that we have changed in the manuscript and the Supplementary Materials.)\nReviewer #1:\nThe authors have addressed my concerns. I would like to recommed publishing this work in\nNature Communications.\nReply: We are sincerely grateful to the reviewer for support and the recommendation for\npublication of our work.\nReviewer #2:\nThank you a lot for the implementation of my suggestions. I see all of the points sufficiently\naddressed. Last minor changes: I would recommend to transfer figure R13 to the supplementary\nand reference to it in the manuscript to have the thickness measurements in. Further, I would like\nto motivate minor changes of the manuscript that clarify the terms “control” and “intermediate\nphase” as the authors have correctly explained in the answers. It can be as short as “In the control\ngroup (blade-coated devices without 2OH additive) ...” “In Intermediate Films (after antisolvent\nactivation, before annealing) ...” Alternatively, they could include these references in materials\nand methods as Control group A,B,C or Intermediate Films and reference them properly.\nReply: We are sincerely grateful for the reviewer constructive feedback and the final minor\nsuggestions. We have added the relevant figure to the supplementary information and refined the\ndefinitions and discussions in the revised manuscript as follows:\nThe Original sentence “Quantitative LC–MS analysis reveals that blade-coated films retain\nsubstantially higher NMP concentrations than their spin-coated counterparts processed from the\nidentical precursor (Supplementary Fig. 2a-b)” has been revised as “This quantification relies on a\nlinear calibration establishing the correlation between integrated signal intensity and NMP\nconcentration (Supplementary Fig. 2a). Cross-sectional SEM imaging of the annealed perovskite\nfilms reveals thicknesses of ~592 nm and ~703 nm for spin-coating and blade-coating films,\nrespectively (Supplementary Fig. 2b). Utilization of a standardized extraction protocol ensures\nthat these thickness discrepancies do not bias the LC-MS solvent residue analysis (see the LC-MS\nin Methods and Supplementary Fig. 2c).”\nwet films (following anti-solvent dripping or gas quenching but prior to annealing)…”. The\nOriginal phrase “In the control group…” has been revised to “In the control group (blade-coated\nfilms without any additives)…”.\nWe have also included explicit definitions for the terms namely control group and intermediate\nphase in Methods sections:\nExperimental Groups Definition: In this study, the intermediate phase films/ wet films are defined\nas the films immediately after antisolvent/gas-quenching activation but prior to the thermal\nannealing. The Control group refers to perovskite devices/films fabricated via the blade-coating\nprocess without any additives.\nSupplementary Figure 2Quantification of residual NMP in perovskite intermediate films. (a)\nStandard calibration curve for NMP quantification via LC–MS, establishing the linear between\nintegrated signal intensity and NMP concentrations. (b) The cross-sectional SEM images of\nannealed perovskite films prepared by spin-coating and blade-coating, showing thicknesses of\napproximately 592 nm and 703 nm, respectively (Scale bar, 1 μm). (c) Digital photographs of the\nsample extraction protocol for all wet-film LC-MS analysis, where a fixed film area (1.0 × 2.0 cm2)\nis dissolved in acetonitrile to ensure volumetric normalization. (d) The relative amount of NMP in\nintermediate wet films prepared using the DMF/NMP solvent system after spin-coating and\nblade-coating processes. (e) Comparative NMP concentrations in blade-coated intermediate films\nwith and without 2OH during the gas quenching process. Error bars represent the standard\ndeviation of three independent measurements (n=3)\nReviewer #3:\nAfter carefully reviewing the authors' comprehensive rebuttal and the substantial additional\nexperimental evidence provided, I am now satisfied that the manuscript has successfully addressed\n2\nthe major concerns raised during the initial review. The authors have rigorously validated their\ncentral hypothesis regarding the solvent-precursor interaction time (τint). Furthermore, the\nexpanded characterization now includes module-level validation, which collectively demonstrates\nthat the additive effectively resolves fundamental bottlenecks inherent to upscaling. The authors\nhave also substantially improved the reproducibility of their work by providing comprehensive\nexperimental details, clarifying sample preparation protocols, and adding critical data on thermal\nstability. The impressive device efficiencies (26.5% for small-area devices and 22.0% for\nlarge-scale sub-modules), combined with the now well-substantiated mechanistic insights,\nrepresent a significant advancement in the field of perovskite photovoltaics. Therefore, I\nrecommend acceptance of this manuscript for publication.\nReply: We are sincerely grateful to the reviewer for the positive evaluation and recognition of our\nresearch.\n3"}, {"round": 2, "reviewer_comments": {"reviewer_1": "The authors have addressed my concerns. I would like to recommed publishing this work in Nature Communications.", "reviewer_2": "Thank you a lot for the implementation of my suggestions. I see all of the points sufficiently addressed.\nLast minor changes: I would recommend to transfer figure R13 to the supplementary and reference to it in the manuscript to\nhave the thickness measurements in. Further, I would like to motivate minor changes of the manuscript that clarify the terms\n\"control\" and \"intermediate phase\" as the authors have correctly explained in the answers. It can be as short as\n\"In the control group (blade-coated devices without 2OH additive), ... \"\n\"In Intermediate Films (after antisolvent activation, before annealing) ...\"\nAlternatively, they could include these refrences in materials and methodds as Control group A,B,C or Intermediate Films\nand reference them properly.", "reviewer_3": "After carefully reviewing the authors' comprehensive rebuttal and the substantial additional experimental evidence provided,\nI am now satisfied that the manuscript has successfully addressed the major concerns raised during the initial review. The\nauthors have rigorously validated their central hypothesis regarding the solvent-precursor interaction time (τint). Furthermore,\nthe expanded characterization now includes module-level validation, which collectively demonstrates that the additive\neffectively resolves fundamental bottlenecks inherent to upscaling. The authors have also substantially improved the\nreproducibility of their work by providing comprehensive experimental details, clarifying sample preparation protocols, and\nadding critical data on thermal stability. The impressive device efficiencies (26.5% for small-area devices and 22.0% for\nlarge-scale sub-modules), combined with the now well-substantiated mechanistic insights, represent a significant\nadvancement in the field of perovskite photovoltaics. Therefore, I recommend acceptance of this manuscript for publication."}, "author_response": "Response Letter to Referees\n(Manuscript# NCOMMS-25-68139)\nWe are gratified that all reviewers are satisfied with our revisions and recommend the manuscript\nfor publication in Nature Communications. We have carefully implemented the final minor\nsuggestions from Reviewer 2 to further enhance the clarity of our work. Detailed point-by-point\nreplies to the reviews along with the changes we have made in the manuscript and Supplementary\nInformation are provided below.\n(Notes: For the convenience of the reviewers, at the end of each piece of reply, we quoted the\nfigures and texts that we have changed in the manuscript and the Supplementary Materials.)\nReviewer #1:\nThe authors have addressed my concerns. I would like to recommed publishing this work in\nNature Communications.\nReply: We are sincerely grateful to the reviewer for support and the recommendation for\npublication of our work.\nReviewer #2:\nThank you a lot for the implementation of my suggestions. I see all of the points sufficiently\naddressed. Last minor changes: I would recommend to transfer figure R13 to the supplementary\nand reference to it in the manuscript to have the thickness measurements in. Further, I would like\nto motivate minor changes of the manuscript that clarify the terms “control” and “intermediate\nphase” as the authors have correctly explained in the answers. It can be as short as “In the control\ngroup (blade-coated devices without 2OH additive) ...” “In Intermediate Films (after antisolvent\nactivation, before annealing) ...” Alternatively, they could include these references in materials\nand methods as Control group A,B,C or Intermediate Films and reference them properly.\nReply: We are sincerely grateful for the reviewer constructive feedback and the final minor\nsuggestions. We have added the relevant figure to the supplementary information and refined the\ndefinitions and discussions in the revised manuscript as follows:\nThe Original sentence “Quantitative LC–MS analysis reveals that blade-coated films retain\nsubstantially higher NMP concentrations than their spin-coated counterparts processed from the\nidentical precursor (Supplementary Fig. 2a-b)” has been revised as “This quantification relies on a\nlinear calibration establishing the correlation between integrated signal intensity and NMP\nconcentration (Supplementary Fig. 2a). Cross-sectional SEM imaging of the annealed perovskite\nfilms reveals thicknesses of ~592 nm and ~703 nm for spin-coating and blade-coating films,\nrespectively (Supplementary Fig. 2b). Utilization of a standardized extraction protocol ensures\nthat these thickness discrepancies do not bias the LC-MS solvent residue analysis (see the LC-MS\nin Methods and Supplementary Fig. 2c).”\nwet films (following anti-solvent dripping or gas quenching but prior to annealing)…”. The\nOriginal phrase “In the control group…” has been revised to “In the control group (blade-coated\nfilms without any additives)…”.\nWe have also included explicit definitions for the terms namely control group and intermediate\nphase in Methods sections:\nExperimental Groups Definition: In this study, the intermediate phase films/ wet films are defined\nas the films immediately after antisolvent/gas-quenching activation but prior to the thermal\nannealing. The Control group refers to perovskite devices/films fabricated via the blade-coating\nprocess without any additives.\nSupplementary Figure 2Quantification of residual NMP in perovskite intermediate films. (a)\nStandard calibration curve for NMP quantification via LC–MS, establishing the linear between\nintegrated signal intensity and NMP concentrations. (b) The cross-sectional SEM images of\nannealed perovskite films prepared by spin-coating and blade-coating, showing thicknesses of\napproximately 592 nm and 703 nm, respectively (Scale bar, 1 μm). (c) Digital photographs of the\nsample extraction protocol for all wet-film LC-MS analysis, where a fixed film area (1.0 × 2.0 cm2)\nis dissolved in acetonitrile to ensure volumetric normalization. (d) The relative amount of NMP in\nintermediate wet films prepared using the DMF/NMP solvent system after spin-coating and\nblade-coating processes. (e) Comparative NMP concentrations in blade-coated intermediate films\nwith and without 2OH during the gas quenching process. Error bars represent the standard\ndeviation of three independent measurements (n=3)\nReviewer #3:\nAfter carefully reviewing the authors' comprehensive rebuttal and the substantial additional\nexperimental evidence provided, I am now satisfied that the manuscript has successfully addressed\n2\nthe major concerns raised during the initial review. The authors have rigorously validated their\ncentral hypothesis regarding the solvent-precursor interaction time (τint). Furthermore, the\nexpanded characterization now includes module-level validation, which collectively demonstrates\nthat the additive effectively resolves fundamental bottlenecks inherent to upscaling. The authors\nhave also substantially improved the reproducibility of their work by providing comprehensive\nexperimental details, clarifying sample preparation protocols, and adding critical data on thermal\nstability. The impressive device efficiencies (26.5% for small-area devices and 22.0% for\nlarge-scale sub-modules), combined with the now well-substantiated mechanistic insights,\nrepresent a significant advancement in the field of perovskite photovoltaics. Therefore, I\nrecommend acceptance of this manuscript for publication.\nReply: We are sincerely grateful to the reviewer for the positive evaluation and recognition of our\nresearch.\n3"}]

Decision letter