Scalable solution soaking quenching technique unlocks efficient and durable wide bandgap perovskite solar modules

Domain: neuroscience
Published: 2026-02-16
Editorial outcome: major_revision

Abstract
Wide-bandgap mixed-halide perovskite photovoltaic modules show strong potential for portable chargers, building-integrated photovoltaics, agri-voltaics, and tandem systems, but large-area processing exacerbates crystallization heterogeneity, surface defects, and halide phase segregation. Conventional spin-coating passivation fails to deliver uniform interfacial control at scale. Here, an industrially inspired solution-soaking quenching technique is introduced, in which hot blade-coated wide-bandgap perovskite films (~30 cm2) are immersed in cold SrI2/isopropanol. It enables rapid surface reconstruction and uniform surface passivation, enhances photoluminescence uniformity, improves crystallinity, reduces roughness, and stabilizes halides via gradient Sr2+ incorporation. These effects mitigate tensile stress, optimize energy-level alignment, and suppress light-induced phase separation. Methylammonium-free wide-bandgap small-area (0.04 cm2) devices achieve efficiencies up to 22.03%, while a 10.13 cm2 module delivers 20.32% efficiency with excellent operational stability. The method is versatile across wide-bandgap perovskite compositions and enables practical applications including portable chargers, semitransparent modules (18.41% bifacial equivalent efficiency), and >27% efficient all-perovskite tandem windows.

Introduction
Perovskite solar cells (PSCs) have gained widespread research attention in the field of photovoltaics due to their remarkable power conversion efficiencies (PCEs) and low-cost manufacturing processes1. Recent advances demonstrated that small-scale laboratory PSCs (active area <0.1 cm2) have achieved certified PCEs approaching 27%, which is comparable to the performance of commercial crystalline silicon solar cells2. Notably, by tailoring the bandgap properties of perovskite materials, functional devices can be designed for specific application scenarios. Among them, mixed-halide wide-bandgap (WBG) perovskite materials, owing to their larger bandgap (range: 1.6–2.0 eV), theoretically maintain higher optical transparency and achieve higher open-circuit voltage (VOC), showing unique advantages in semi-transparent photovoltaic devices and tandem solar cells3,4. This offers promising potential for the development of next-generation photovoltaic technologies and products.

Currently, the mainstream WBG perovskite system predominantly adopts mixed-halide formulations with high bromine (Br) content. However, inherent issues such as differences in crystallization dynamics between different halides, halide phase segregation, and ion migration induced by external factors (e.g., light, temperature, and moisture) lead to poor crystallization quality, significant chemical compositional inhomogeneity, and abundant bulk/surface defects in perovskite thin films5–7. These drawbacks collectively cause severe interfacial non-radiative recombination and carrier transport losses, thereby constraining further improvements in efficiency and operational stability. Blade-coating, as a scalable large-area thin film deposition technique, has demonstrated considerable industrialization potential due to its low ink consumption and high compatibility with roll-to-roll processing8. However, during the blade-coating of large-area WBG perovskite films, the crystallization heterogeneity of mixed-halide components exacerbates the aforementioned uneven crystallization and abundant interfacial defects, resulting in the degradation of key photovoltaic parameters across the solar modules, ultimately leading to performance deterioration9. For instance, when scaling up high-efficiency small-area cells (<1 cm2) to modules (>10 cm2), a pronounced PCE roll-off exceeding 4% is often observed, posing a critical barrier to commercialization and practical development10. Notably, the reduction in fill factor (FF) induced by device scaling is more significant than the reductions in short-circuit current density (JSC) and VOC11–13. This phenomenon is primarily attributed to the amplification effect of interfacial imperfections, inhomogeneous carrier transport paths, and accelerated degradation of interfacial properties at larger scales, which collectively lead to a significant increase in series resistance (RS) at the interfaces14,15.

Studies have demonstrated that introducing organic/inorganic small molecules or modifying the interface between the perovskite layer and the electron transport layer (ETL) can optimize the interfacial contact and enhance charge extraction dynamics, thereby improving the JSC and FF of PSCs16–18. For example, Liu et al. sequentially deposited ethylenediamine diiodide (EDAI2) and 4-fluoro-phenethylammonium chloride (4F-PEACl) to improve the interfacial contact between perovskite and the C60 ETL, effectively alleviating interfacial energy losses and enhancing charge extraction efficiency, achieving a breakthrough in the performance of WBG perovskite/silicon tandem solar cells19. Similarly, Jiang et al. used cyclohexane 1,4-diammonium diiodide (CyDAI2) as an interfacial passivation material, successfully suppressing defect states at the WBG perovskite/ETL interface, significantly reducing interfacial recombination and enhancing PCE, achieving an outstanding efficiency of 26.4% in WBG perovskite/organic tandem solar cells20. However, conventional interface modification strategies for PSCs and modules mainly rely on spin-coating, which is limited by solvent evaporation-induced conventioneffects (i.e., the well-known coffee-ring effect), resulting in uneven distribution of the modification solution and aggregation of additives at the edges of perovskite films21,22. As the device area increases, this phenomenon becomes more pronounced, making it difficult to precisely control the spatial distribution of modifying ions. This unevenness often leads to localized chemical composition variations on the film surface, which in turn adversely affects surface optoelectronic properties such as charge transport efficiency. The spatial heterogeneity at the interface severely disrupts the uniformity of charge transport, becoming a critical bottleneck for the scalable fabrication of high-performance photovoltaic modules. Furthermore, methylammonium cations (MA+), widely used in WBG perovskite systems, suffer from thermal instability, severely limiting outdoor applications. The high volatility of MA+ at elevated temperatures easily triggers phase separation and defect proliferation, leading to structural degradation23,24. Studies have shown that MA+-driven crystallization disorders resulted in more grain boundaries and interfacial defects25,26. Therefore, it is highly desirable and imperative to develop simple, scalable, and universal post-treatment methods to enhance surface chemical homogeneity, optimize interfacial contact, suppress interfacial defect states, and improve interfacial charge transport efficiency, which is of great significant for advancing the performance of large-area WBG photovoltaic devices.

Inspired by traditional manufacturing processes, the quenching technique used in the rapid cooling of hot-processed metal materials can effectively improve material performance. By precisely controlling the cooling rate, this technique enhances material hardness and strength while relieving stress and thermal deformation, making it a key process in modern industrial manufacturing27,28. In this work, we innovatively introduce industrial quenching technology into the photovoltaic field for post-treatment of large-area perovskite films to enhance their optoelectronic performance. Specifically, a quenching medium based on cold SrI2/IPA solution is developed for rapid soaking treatment of hot perovskite films. This approach achieves uniform and efficient surface/interface modification of large-area perovskite films at the macroscopic scale. This cold and hot shock-driven surface reconstruction strategy substantially enhances the crystallinity of the films and reduces surface roughness by 53%. Simultaneously, through gradient doping of metal ions from film surface to bulk interior, coupled with halide stabilization, the crystallization-induced tensile stress is effectively relieved, energy level alignment is optimized, and the surface homogeneity and interfacial charge transport efficiency of large-area films are significantly enhanced. The solution-soaking quenching (SSQ) technique demonstrates universal compatibility, effectively treating various mainstream WBG compositions and realizing the synergistic integration of multifunctional organic solutes in the quenching medium. Notably, the optimized blade-coated small-area (0.04 cm2) devices with bandgaps of 1.65, 1.68, and 1.78 eV attain remarkable PCEs of 22.03%, 21.39%, and 18.66%, respectively. The SSQ strategy is suitable for other MA-free perovskite systems with different bandgaps, validating the universality of this approach. After scaling up to large-area modules, the enhanced chemical uniformity of surface modification/passivation molecules dramatically enhances the photoluminescence (PL) intensity and simultaneously reduces the coefficient of variation in fluorescence intensity from 17.16 to 0.67%, effectively solving the scaling-up problem while retaining the high efficiency and stability characteristics validated in small-area devices. This optimization results in a 63% reduction (from 17.45 to 6.52 Ω) in overall RS, thereby significantly boosting the FF of the WBG perovskite solar modules (PSMs) from 69.95% to 80.44%. Ultimately, the champion PCEs of 20.32% (active area: 10.13 cm2) are achieved, representing one of the highest reported values for such a type of device. Encapsulated MA-free PSMs exhibit remarkable thermal stability, retaining 87% of their initial PCE after 550 h of thermal aging at 65°C according to the ISOS-D-2I protocol. In addition, encapsulated devices maintain more than 96% of their initial PCE after over 1000 h of continuous maximum power point (MPP) tracking under the ISOS-L-1 standard at room temperature (25°C) and 50–60% relative humidity, demonstrating superior stability compared to most solution-processed WBG perovskite devices29,30. Furthermore, this technology is successfully extended to diverse application scenarios, such as semi-transparent WBG PSMs suitable for agricultural photovoltaics (a bifacial equivalent efficiency of 18.41%, 17.55% average visible light transmittance (AVT)) and four-terminal switchable all-perovskite tandem photovoltaic windows for building-integrated photovoltaic windows (translucent mode: 17.22% PCE; opaque maximal energy harvesting mode: 27.12% PCE), as well as portable charging devices. By overcoming the core challenge of large-area perovskite film post-treatment uniformity, this study provides a practical technical solution to simultaneously enhance device performance and scalability. These advancements highlight the potential of perovskite photovoltaics to expand into commercial applications and adapt to diverse application scenarios, bridging the gap between laboratory innovations and industrialization requirements.

Results
Surface homogenization in large-scale perovskite films

In modern industry, quenching technology rapidly cools metals that have been heated to high temperatures, which helps homogenize their surface and increases surface hardness. Precisely controlling the temperature differences between hot and cold, as well as the cooling rate, can optimize the microstructure and generate compressive stress that inhibits crack formation, significantly enhancing the material’s durability. This process has become a core technique in precision industries such as aerospace and automotive manufacturing. Inspired by this industrial metallurgical approach, we have innovatively implemented a quenching-like post-treatment strategy by quickly cooling large-area perovskite films with a cold quenching solution (Fig. 1a), in order to enhance their surface homogeneity and optoelectronic performance. As a case study, this research first focused on mixed-halide WBG (FA0.8Cs0.2Pb(I1-xBrx)3) perovskite films. Specifically, the blade-coated perovskite films were immediately soaked in a 5°C SrI2/isopropanol (IPA) quenching medium after conventional thermal annealing at 105°C, rather than cooling naturally (see the detailed experimental details in “Methods section”). The inherent thermodynamic instability of the initial film is activated by the kinetic shock of quenching, guided by the chemical potential gradient of the solution, and subsequently stabilized through the thermal energy of the final annealing tempering step, ultimately resulting in gradient doping and comprehensive surface reconstruction (Supplementary Fig. 1). This controlled rapid cooling process simultaneously achieved gradient doping of Sr2+ from the surface to the bulk interior of the film (will be discussed later), along with grain boundary reconstruction, thereby enhancing the structural toughness of the crystals and effectively suppressing grain boundary defect formation.

Scanning electron microscope (SEM) analysis (Fig. 1b) revealed that the control blade-coated WBG perovskite film exhibited a polycrystalline structure with obvious voids between adjacent grains and uneven grain size distribution, accompanied by an atomic force microscopy (AFM)-measured root mean square (RMS) roughness of 13.2 nm (Supplementary Fig. 2). These undesirable morphological features were prone to the formation of deep-level defect states, which acted as Shockley-Read-Hall recombination centers, substantially exacerbated carrier loss and reduced carrier lifetimes. In contrast, the SSQ-derived films demonstrated remarkable morphological improvement (Fig. 1c), with densely interlocked grains and a 53% reduction in surface roughness (a RMS of 6.2 nm, Supplementary Fig. 3). To quantitatively substantiate these morphological and crystallographic improvements, statistical analysis of grain size distribution from relatively larger-area regions of SEM images was conducted. As depicted in Supplementary Fig. 4, the SSQ-treated perovskite film exhibited more uniform grain size distribution, with the average grain size increasing from 224.1 nm for the control to 242.3 nm. Furthermore, XRD patterns collected from five distinct regions of the large-area (5.2 cm × 6.0 cm) SSQ-treated film showed virtually similar perovskite characteristic peaks without any detectable secondary phases/impurities (Supplementary Figs. 5 and 6), demonstrating excellent phase purity and uniformity across a large-area dimension. These quantitative data unequivocally confirmed that the SSQ treatment indeed promoted the growth of more uniform and high-quality perovskite films with enhanced crystalline properties, which underpinned the improved photovoltaic performance. This improvement is attributed to solvent-mediated surface etching in the quenching solution and passivation molecule-assisted surface reconstruction caused by the cool-thermal shock. Notably, when using the same SrI2/IPA solution, under the same temperature difference conditions, the spin-coated (SC) post-treatment merely reduced the roughness to 11.6 nm (Supplementary Figs. 7 and 8). This limitation originates from Marangoni convection during the conventional spin-coated post-treatment, where differential solvent evaporation rates on the wet-film surface create radial temperature and concentration gradients, leading to solute accumulation at the depleted edges (coffee-ring effect). Such inhomogeneous deposition hinders uniform surface reconstruction and induces localized chemical heterogeneity. This effect becomes more pronounced as the film area increases, causing discontinuities in carrier transport channels and large interfacial charge transport barriers. In contrast, our SSQ technique completely circumvents this issue by immersing the entire film into the quenching solution, thereby eliminating the convective flows-induced coffee-ring effect and non-uniformities. This ensures a homogeneous and isotropic supply of SrI2 across the entire film surface, guaranteeing uniform surface morphology and comprehensive defect passivation, showing a decisive advantage for scalability.

To systematically evaluate the scalability of the SSQ strategy, we extended the spatial homogeneity analysis to blade-coated WBG perovskite films of different dimensions (1.5 cm × 1.5 cm, 3.5 cm × 3.5 cm, and 5.2 cm × 6.0 cm) and performed spatially resolved photoluminescence (PL) mapping tests on 5, 7, and 13 designated regions, respectively. For the perovskite films of different sized dimensions, both SC and SSQ post-treatments effectively enhanced the PL intensity. One could notice the PL intensity of SC-treated films always decreased at the edges, as compared to the central region, leading to strong spatial nonuniformity, regardless of film areas. As the film area increased to 5.2 cm × 6.0 cm, such a limitation of the SC method became more evident. In comparison, the SSQ-treated films maintained exceptional PL uniformity across all regions and all film sizes (Supplementary Figs. 9 and 10, Fig. 1d, e). Typically, for the largest-area WBG perovskite film (5.2 cm × 6.0 cm) tested on 13 designated regions, the PL intensity of the central region (Region 7) showed the same enhancement trend as the small-area samples (Fig. 1e, Supplementary Fig. 11), with substantially amplified PL intensity after SrI2/IPA post-treatment. Bright-field microscopy imaging (Fig. 1f) and confocal PL mapping images (Fig. 1g–i) revealed that in the SC post-treated films, the PL intensity of the edge region decreased by ~40% compared to the central region, primarily due to the significant central-to-edge gradient in modified ion distribution, where excessive SrI2/IPA accumulated at the edges, leading to elevated non-radiative recombination centers. In stark contrast, the SSQ-derived films demonstrated exceptional surface homogeneity over a large scale, with the coefficient of variation (CV) of PL intensity reduced from 17.16% (SC film) to 0.67%. This improvement in surface passivation uniformity resulted from selective etching at the solid-liquid interface mediated by the quenching solvent and passivation ions-assisted surface reconstruction and localized structural reorganization. The synergistic optimization of morphological homogenization and uniform surface defect passivation is expected to improve interface contact and charge transport performance with other functional layers, providing a scalable solution for the fabrication of high-performance large-area perovskite optoelectronic devices.

Halide homogenization and stabilization

The nucleation and crystallization dynamics of blade-coated perovskite precursors are fundamentally governed by the synergistic interplay between thermodynamic driving forces (e.g., supersaturation) and kinetic constraints (e.g., solvent evaporation rate). As illustrated in Fig. 2a, during blade-coating, solvent evaporation driven by surface tension at the air-liquid interface induces preferential surface-initiated crystallization of the wet film, resulting in a top-down crystallization mechanism31,32. In WBG perovskites, the use of mixed-halide compositions introduces additional complexity due to the varying reactivity and volatility of halide components. As a result, the spatial heterogeneity in chemical composition emerges, leading to pronounced halide segregation and the formation of abundant halide vacancies33,34. Under sustained light exposure or thermal stress, this segregation worsens, producing I-rich and Br-rich domains that serve as trap centers for photogenerated carriers35. This amplifies non-radiative recombination and causes significant open-circuit voltage (VOC) losses36. More critically, this undermines the operational stability of WBG PSCs37. Mechanistically, the smaller ionic radius of Br- facilitates its preferential migration through vacancy-mediated pathways, exacerbating phase separation (Fig. 2b). This effect intensifies with increasing bromine content in the perovskite formulation38. Surface treatment strategies, particularly those involving customized passivation layers or buffer interfaces, have shown promise in regulating halide distribution (e.g., via halide compensation) and suppressing ion migration (Fig. 2c)39,40. However, conventional solution-coating treatments typically only modify the top surface of the perovskite film, offering minimal stabilization of halide ions in the bulk or at the bottom interface.

To probe the effectiveness of different surface treatments, we performed depth-profile analysis using time-of-flight secondary ion mass spectrometry (ToF-SIMS) on perovskite films treated with SrI2/IPA SC and SrI2/IPA SSQ, respectively. As shown in Fig. 2d, e, both treatments successfully introduced Sr2+ into the film and modulated halide distribution. Sr2+ ions (ionic radius of 1.118 Å) from the halide salt could partially substitute Pb2+ (ionic radius of 1.190 Å), as is verified by consistent shift of diffraction peaks to higher angles in XRD patterns owing to lattice contraction (Supplementary Fig. 12), preferentially coordinated with halide ions (Br⁻, I⁻), stabilizing them and suppressing their migration, while also filling halide vacancies41–43. To directly probe the surface chemical modification and iodine vacancy compensation induced by the SSQ treatment, we performed X-ray photoelectron spectroscopy (XPS) on both control and SrI2/IPA SSQ-treated perovskite films, providing quantitative information on surface I/Pb atomic ratios. Survey XPS spectra for these two samples were shown in Supplementary Fig. 13a. For the mixed-halide FA0.8Cs0.2Pb(I0.8Br0.2)3 perovskite compositions, the theoretical I/Pb ratio is 2.4. However, the average I/Pb ratio measured on the surface of the control perovskite film was only 2.07, revealing a pronounced iodine-deficient surface characteristic. After SrI2/IPA SSQ treatment, the surface I/Pb ratio exhibited a remarkable increase to 2.26 (Supplementary Fig. 13b). Even considering the potential partial substitution of Pb2+ by Sr2+, the adjusted I/(Pb+Sr) ratio still reached ~2.24, which remained substantially higher than that of the control film. This unambiguously demonstrated that the SSQ treatment effectively mitigated surface iodine loss by supplying additional iodide ions from the quenching medium, thereby filling undesirable iodine vacancies39,44. Notably, the spin-coated treatment limits Sr2+ penetration depth, resulting in a gradient in mixed-halide ion concentrations, decreasing from top down, which fostered inhomogeneous halide distribution and I/Br-enriched domains formation, compromising film uniformity. In contrast, films treated via SSQ exhibited more uniform halide distribution across both the bulk and interfaces. This improvement was attributed to the unique cold/thermal shock mechanism of the SSQ process. During perovskite lattice expansion, Sr2+ penetrated deeply, and the subsequent rapid cooling locked more portions of Sr2+ ions within the lattice, forming stable Sr-halide complexes through chemical bonding. These complexes acted as structural bridges that relieve lattice stress (further discussed later), effectively suppressing halide ion migration and phase segregation. This comparison highlighted the critical role of the SSQ strategy in achieving halide homogenization throughout the WBG perovskites. To unravel the kinetics of Sr2+ incorporation, we monitored the evolution of passivation by measuring the PL intensity from both the front and rear sides of the film after quenching and during subsequent tempering (Supplementary Fig. 14). The front-side PL intensity increased immediately after quenching and saturated after 80 s, indicating rapid surface passivation. In contrast, the rear-side PL intensity remained low without tempering and increased gradually upon annealing, saturating after ~100 s. This delay demonstrated that Sr2+ doping occurred via a time-dependent, solid-state diffusion process during tempering, enabling the passivating species to propagate from the surface into the bulk, thereby achieving comprehensive film improvement.

To evaluate the thermal stability of WBG perovskite materials, we conducted temperature-dependent photoluminescence (PL) measurements. As shown in Supplementary Fig. 15, PL intensity of all three perovskite films decreased with rising temperature, primarily due to exciton dissociation into free carriers, which preferentially underwent non-radiative recombination via defect states or lattice vibrations45. For the control perovskite, PL intensity dropped by 50% between 140 and 160 K. In contrast, the SrI2-quenched sample demonstrated substantially mitigated thermal-induced fluorescence-quenching behavior, maintaining relatively high PL intensity up to 300 K. This improvement in thermal stability was attributed to the uniform incorporation of Sr2+ halide salts during post-treatment, which effectively passivated halide vacancies at both surfaces and in the bulk, stabilizing the lattice and suppressing defect-assisted non-radiative recombination. In-depth analysis of normalized PL spectra from 100 to 320 K (Fig. 2f–h) revealed distinct temperature responses. The control film exhibited progressive PL broadening (increased full width at half maximum, FWHM) and blueshifts with increasing temperature, signatures of intensified exciton-phonon coupling and thermally-induced halide segregation (Supplementary Fig. 16). While the SrI2/IPA SC-treated film showed temperature-independent FWHM, the overall narrowing was modest, reflecting the dominance of surface passivation with limited bulk effect, and a trade-off with thermally activated broadening. In contrast, the solution-soaked, quenched film displayed a narrower FWHM at 320 K (32 nm vs. 41 nm for control), indicating a robust crystal structure reinforced by surface reconstruction and structural rearrangement. This was enabled by synergistic passivation of both surface and bulk defects, effectively mitigating thermally induced lattice distortion and phase segregation. Such temperature-insensitive PL characteristics and enhanced optoelectronic homogeneity underscore a promising pathway toward high-performance perovskite-based optoelectronic devices through comprehensive defect passivation and structural stabilization strategies. Additionally, the dynamics of light-induced halide segregation and phase separation were monitored via time-resolved in-situ photoluminescence (PL) spectroscopy. Different wide-bandgap perovskite films were subjected to continuous irradiation under ambient atmospheric conditions. As shown in Supplementary Fig. 17, the PL peak of the control film, initially centered at 748 nm, exhibited a pronounced red shift over 20 min of light exposure, accompanied by a broadening of FWHM to 47.03 nm. This spectral evolution indicated the formation and accumulation of lower-bandgap (I-rich) perovskite domains, which may promote non-radiative carrier recombination across phase-segregated regions46,47. In stark contrast, the SSQ-treated mixed-halide WBG perovskite films showed negligible peak shift and FWHM broadening under identical conditions, with only a minor decrease in PL intensity. These results highlighted the effectiveness of the SSQ technique in mitigating light-induced halide segregation and maintaining phase stability in mixed-halide WBG perovskites.

Surface reconstruction and residual stress mitigation

We directly visualized the vertical morphological features of the WBG perovskite films using cross-sectional SEM characterization. As shown in Supplementary Fig. 18a, the untreated control film exhibited pronounced voids between adjacent grains. These voids are primarily attributed to incomplete solvent evaporation during crystallization, which constrained the grain growth and resulted in a higher density of grain boundaries and related defects. Such morphological features not only introduce non-radiative recombination centers but also provide diffusion pathways for moisture, oxygen, and mobile ions, thereby accelerating device degradation. In stark contrast, the SrI2/IPA SSQ-treated film displayed a tightly packed grain structure (Supplementary Fig. 18b), confirming that the SSQ post-treatment effectively promoted grain fusion and film densification, consistent with surface SEM observations (Fig. 1b, c) discussed earlier. This optimized morphology significantly reduced the number of grain boundaries and the overall defect density. The resulting compact microstructure is beneficial for efficient charge transport and serves to suppress environmentally-induced degradation pathways, laying a robust foundation for enhanced device efficiency and operational stability. To further assess the crystalline and structural quality across the film thickness, we performed depth-resolved grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements. By systematically tuning the incident angle (2°, 1.5°, and 1°) to modulate the X-ray penetration depth, we evaluated the depth-dependent crystallinity of the perovskite films from the top surface to the bottom interface48. As shown in Fig. 3a–i, the control film exhibited weak surface diffraction signals that rapidly attenuated with increasing depth, reflecting poor overall crystallinity and pronounced spatial inhomogeneity in crystal quality. In comparison, the SrI2/IPA SSQ-treated film displayed significantly enhanced diffraction intensity and sharper Debye-Scherrer rings under higher incidence angles (2°), corresponding to the surface-sensitive region. This observation highlighted the markedly improved surface crystallinity achieved through quenching. Notably, even at reduced incidence angles of 1.5° and 1°, which probed deeper regions of the film, the SrI2/IPA SSQ-treated sample consistently exhibited the strongest diffraction signals among all three groups. In contrast, the SrI2/IPA SC-treated film showed a noticeable signal drop at 1°, with intensities approaching those of the untreated control. These comparative results reaffirmed that the conventional SrI2/IPA spin-coating treatment predominantly improved crystallinity near the film surface but failed to enhance the bulk crystal quality. Conversely, the SrI2/IPA SSQ approach enabled solution-mediated surface reconstruction and structural reorganization driven by the cooperative effects of solute and solvent. This process uniformly enhanced crystallinity throughout the entire film thickness, from the top surface to the buried interface, achieving a comprehensive improvement in film structure. The optimized morphology and enhanced crystallinity achieved by the SSQ treatment are expected to directly benefit the optoelectronic properties of the perovskite films. As shown in Supplementary Fig. 19, the SSQ-treated film exhibited significantly stronger light absorption capability than that of the control film, establishing a solid foundation for generating higher photocurrent in the complete PSCs (will be discussed in the following section).

Residual stress naturally arises in thin-film materials and devices during fabrication, processing, and operation. This stress primarily originates from mismatches in thermal expansion coefficients between the substrate and the film, lattice mismatches, structural defects such as vacancies, and process-related factors like solvent evaporation and cooling rates49–51. Notably, residual tensile stress can cause lattice expansion, weaken chemical bonds, and reduce the formation energy of defects. These changes exacerbate non-radiative carrier recombination, severely comprising the optoelectronic performance of perovskite materials and devices52. Moreover, tensile strain can elongate ion diffusion paths, facilitate ion migration, and accelerate phase segregation and interfacial corrosion. Such phenomena would be further intensified under light, heat, and moisture, thus posing a significant threat to device stability53. In large-area perovskite films, uneven thermal conduction across the substrate can generate temperature gradients (e.g., rapid cooling at the edges versus thermal retention at the center), inducing nonuniform thermal expansion and contraction. This results in macroscopic stress zones, typically compressive at the edges and tensile at the center54,55. Such spatially heterogeneous stress distributions magnified the effects of residual stress in large-area perovskite thin films, limiting both the efficiency and long-term stability of large-scale perovskite photovoltaic modules.

We systematically investigated the residual stress (δR) in the control, SrI2/IPA SC-treated, and SrI2/IPA SSQ-treated WBG perovskite films using grazing incidence X-ray diffraction (GIXRD). The measurements were conducted at a fixed 2θ angle while varying the instrument tilt angles (Ψ), maintaining consistent penetration depth (Fig. 3j–l). The δR was calculated from the linear plot of 2θ as a function of sin2Ψ, according to the stress equation:

δR = [E / (1 + ν)] * [cotθ0 / 18] * [∂(2θ) / ∂(sin2Ψ)] (1)

where E represents the Young’s modulus (17.8 GPa for perovskites), ν represents the Poisson’s ratio (≈0.33), and θ0 represents half of the scattering angle 2θ for stress-free perovskite56. The XRD signal at 32.1° corresponded to the (210) facet of the perovskite film was chosen for analysis, which minimized orientation effects and provided more reliable information on structure symmetry52. For the control film, the diffraction peaks shifted progressively toward lower 2θ values as Ψ increased from 5° to 45° (Fig. 3j), indicating a monotonic increase in crystal plane distance of the (210) facet, clear evidence of the presence of residual tensile stress within the perovskite film. Fitting the 2θ as a function of sin2Ψ yielded a δR of 51.76 MPa. In contrast, the SrI2/IPA SC-treated film showed reduced peak shifts and a lower δR of 44.68 MPa. The SrI2/IPA SSQ-treated film exhibited the smallest peak shift and a further reduced slope (-0.09) in the fitted curve, corresponding to the lowest δR of 36.83 MPa (Fig. 3m, n). This stress relief was attributed to surface reconstruction and lattice reorganization mediated by the SrI2/IPA soaking and quenching process. Specifically, the substitution of Pb2+ by Sr2+ allows for subtle lattice adjustments due to their similar ionic sizes but differing bonding characteristics, alleviating lattice mismatch and modulating internal stress. On one hand, Sr2+ doping could introduce compensatory compressive stress through stronger halide bonding or localized lattice contraction. On the other hand, Sr2+ could stabilize halide ions, reducing defect-induced lattice distortion and associated elastic strain energy. Unlike surface-limited spin-coating, the quenching post-treatment facilitated deeper infiltration of SrI2/IPA into grain boundaries and voids, triggering localized dissolution-recrystallization. This promoted grain fusion and interfacial smoothing, effectively releasing interfacial strain. These findings demonstrated that SrI2/IPA-assisted SSQ post-treatment synergistically enhanced film quality by enabling smooth, dense perovskite growth, mitigating lattice mismatch, and relieving residual stress through compositional engineering (Sr2+ doping and halide compensation) and surface reconstruction. Consequently, this strategy significantly improved the mechanical robustness and environmental resilience of perovskite films, extending the operational lifespan of corresponding optoelectronic devices.

Energy level modulation and carrier dynamics optimization

Surface treatments can markedly influence the surface electronic properties of perovskite films. To investigate the impact of SrI2/IPA post-treatments on the surface energy levels of WBG perovskite films, we performed ultraviolet photoelectron spectroscopy (UPS) measurements. By calculating the energy difference between the incident HeI photon energy (21.22 eV) and the binding energy corresponding to the secondary electron cut-off edge, as shown in Supplementary Fig. 20, the Fermi level (EF) of the perovskite films can be calculated. As shown in Fig. 4a, the EF uplifted from -4.37 eV for the control sample to -4.32 eV for the SrI2/IPA SC film, and further to -4.26 eV for the SrI2/IPA SSQ film. This result indicated that the SrI2/IPA post-treatment, particularly the quenching process, elevated the EF closer to the conduction band (CB), characteristic of n-type doping. This trend aligns well with previous reports on metal halide salt treatment, which suggested simultaneous electron and defect compensation effects leading to beneficial doping behavior57. Considering the WBG perovskite’s bandgap of 1.68 eV (discussed later) and the UPS-derived valence band (VB) positions, we found that the SrI2/IPA quenching process also induced a slight downward shift in the CB. Combined with the favorable band bending induced by n-type doping, this adjustment reduced the energy barrier at the perovskite/electron transport layer (ETL) interface, facilitating more efficient interfacial electron extraction and thus enhancing device performance.

To probe the ultrafast carrier dynamics within the device and at the interface, we performed femtosecond transient absorption (fs-TA) spectroscopy on the semi-devices with the stacked architecture of ITO/PTAA/2-PACz/perovskite with or without SrI2/IPA treatment/C60 (Fig. 4b). Photoinduced charge transfer typically occurs over sub-picosecond to nanosecond timescales. By varying the pump-probe delay time and tracking changes in transient absorption (ΔA), we captured the dynamic behavior of excited-state carriers over time, revealing their relaxation into lower energy states. As shown in the fs-TA contour maps (Fig. 4c, d), both the control and SrI2/IPA SSQ-treated semi-devices exhibited prominent ground-state bleaching (GSB) peaks near 740 nm. The decay rate of the GSB signal reflects the efficiency of photogenerated carrier extraction from the perovskite layer to adjacent charge transport layers. Compared to the control, the SrI2/IPA SSQ-treated samples showed significantly faster GSB signal decay, indicating more efficient carrier extraction. This rapid GSB decay suggested a swift depletion of photogenerated carriers, effectively reducing recombination probabilities and shortening the duration of ground-state bleaching. This improvement can be attributed to enhanced crystallinity, improved interfacial chemical homogeneity, and optimized energy level alignment resulting from the SrI2/IPA SSQ treatment, which collectively promoted directional carrier migration.

Time-resolved TA spectra (Fig. 4e, f) further corroborated this conclusion. At identical delay times, the SrI2/IPA SSQ-treated semi-device exhibited flatter GSB peak signals, as compared to that of the control, indicating a shorter carrier residence time. The decay kinetics of GSB were analyzed via bi-exponential fitting according to the equation:

τavg = (A1τ1^2 + A2τ2^2) / (A1τ1 + A2τ2) (2)

where A1 and A2 are the amplitudes of the fast and slow decay components, respectively. τ1 and τ2 represent the time constants for fast and slow decay components, respectively58,59. The results revealed a significantly reduced decay lifetime for the SrI2/IPA SSQ-treated sample (303.3 ps) compared to the control (779.2 ps) (Fig. 4g and Supplementary Table 1). This outcome provided additional evidence that the SrI2/IPA quenching process synergistically improved carrier dynamics through crystallization control, interface modification, and energy level optimization. Altogether, these enhancements enabled more efficient charge transfer and collection at the perovskite/charge transport layer interfaces, mitigating interfacial non-radiative recombination losses. As a result, the photocurrent output and fill factor are expected to be improved, underscoring the critical role of this post-treatment strategy in boosting the photovoltaic performance of PSCs.

Photovoltaic performance and stability

To evaluate the effect of the SSQ strategy on the photovoltaic performance of blade-coated MA-free WBG PSCs, we fabricated devices with the structure of ITO/PTAA/2-PACz/FA0.8Cs0.2Pb(I1-xBrx)3 perovskite with or without SSQ/C60/bathocuproine (BCP)/Ag (Fig. 5a). Figure 5b compares the current density-voltage (J-V) characteristics of the PSCs without or with SrI2/IPA SSQ post-treatment, with corresponding photovoltaic parameters summarized in Table 1. Under simulated AM 1.5G one-sun irradiation (100 mW cm−2), the control device yielded a reverse-scan power conversion efficiency (PCE) of 16.91%, with a short-circuit current density (JSC) of 19.90 mA cm−2, open-circuit voltage (VOC) of 1.18 V, and fill factor (FF) of 72%, while the average PCE was 14.97% ± 0.84%. In contrast, devices treated with SrI2/IPA SSQ exhibited a substantial improvement in PCE. The champion device achieved a PCE of 21.39%, with a VOC of 1.21 V, JSC of 21.68 mA cm−2, and FF of 81.26%, showing negligible hysteresis. This represents one of the highest reported efficiencies for small-area WBG (~1.68 eV) PSCs fabricated via blade-coating (Supplementary Table 2). The forward-scan PCE was 20.94% (VOC = 1.20 V, JSC = 21.46 mA cm−2, FF = 81.30%), and the average PCE was 20.28% ± 0.54%. In comparison, the SrI2/IPA SC devices merely reached a PCE of 20.03% (FF = 78%), which could be attributed to the moderate modification effect induced by such surface-only treatments (Supplementary Fig. 21). This contrast underscores the superior performance enhancement enabled by the soaking-quenching approach.

Notably, SSQ treatment performed at 5°C helped to realize the optimal device photovoltaic performance (Supplementary Fig. 22 and Supplementary Table 3), which can be attributed to sufficient cold-thermal shock to drive favorable surface reconstruction. The SrI2/IPA concentration was optimized from 0.05 mg mL−1 to 0.50 mg mL−1, with 0.20 mg mL−1 yielding the best device photovoltaic performance (Supplementary Fig. 23 and Supplementary Table 4). Particularly, the versatility of the SSQ approach is confirmed by employing EDAI2/IPA as the quenching medium, which also yielded a high PCE of 20.21% (Supplementary Fig. 24), indicating that the SSQ post-treatment is applicable to other salts beyond SrI2. The steady-state output of the best-performing SrI2/IPA SSQ-treated device was shown in Fig. 5c, exhibiting a stabilized PCE of 21.05% over 120 s at the maximum-power-point of 1.05 V. External quantum efficiency (EQE) measurements corroborated the enhanced JSC. Compared to the control, the SrI2/IPA SSQ-treated PSC exhibited remarkably enhanced EQE across the 300–750 nm spectral range (Fig. 5d). The integrated current density derived from EQE spectrum (i.e., 20.61 mA cm−2 for SrI2/IPA SSQ-treated PSC vs. 19.07 mA cm−2 for the control PSC) was in good accordance with the J-V results, showing a discrepancy <5%.

EQE-based bandgap analysis (Supplementary Fig. 25) indicated the bandgap remained unchanged at 1.68 eV after quenching treatment. The decline in EQE at longer wavelengths is attributed to Urbach tail states caused by structural defects, impurities, and lattice dislocation60. The Urbach energy (EU) can be calculated from the EQE spectra using the following equation:

α = α0 exp(hν / EU) (3)

in which α is the absorption coefficient, α0 is a constant, and hν is the photon energy (E)61. A reduction in EU (23.32 meV vs. 24.58 meV) confirmed that the quenched films exhibited reduced lattice disorder, fewer defects, and improved energetic uniformity. The overall enhancement in device performance was attributed to concurrent improvements across all photovoltaic parameters. The increases in JSC and FF stemmed from enhanced crystallinity, improved conductivity, better compositional homogeneity, and more efficient interfacial carrier extraction and transport. The enhancement of VOC by ~30 mV was primarily due to suppressed trap-assisted recombination, resulting from a reduced defect density. To probe the origin of the FF enhancement, illumination intensity-dependent photoluminescence quantum yield (PLQY) measurements and quasi-Fermi level splitting (QFLS) analyses (from 0.001 to 2 suns) were performed (Supplementary Fig. 26). The SrI2/IPA SSQ-treated film exhibited a steeper increase in PLQY, consistently higher absolute PLQY values across all measured illumination intensities, and a lower ideality factor (nid) (i.e., 1.38 vs. 1.41 for the control), demonstrating suppressed defect-assisted non-radiative recombination and more ideal diode behavior62,63. We concluded that reduced non-radiative recombination, together with both improved film quality and optimized energy-level alignment, collectively contributed to the significantly improved FF.

To quantify trap density and carrier mobility, we fabricated electron-only devices (ITO/SnO2/perovskite (with or without SrI2/IPA SSQ)/C60/BCP/Cu) for space-charge-limited-current (SCLC) measurements (Fig. 5e, f). The trap densities (Ntrap) were derived from the trap-filled limit voltage (VTFL) via the following equation:

Ntrap = 2VTFL ε0 εr / qL2 (4)

where ε0, εr and L represented the vacuum permittivity, dielectric constant permittivity and film thickness (≈220 nm) of the perovskite film, respectively. As a result, the SrI2/IPA SSQ-treated device exhibited a smaller VTFL (0.18 V) and Ntrap (1.32 × 10^16 cm−3), relative to the control device (a VTFL of 0.29 V and a Ntrap of 2.12 × 10^16 cm−3), representing a 38% reduction in defect states (Fig. 5e). In addition, we further evaluated the electron mobility (μ) of the perovskite films via the SCLC model (Fig. 5f), according to the following equation:

μ = 8L3 J / 9ε0 εr V2 (5)

The SrI2/IPA SSQ-treated film showcased more than 5-fold enhancement of electron mobility compared to that of the control film (1.32 × 10^−3 cm2 V−1 s−1 vs. 2.12 × 10^−4 cm2 V−1 s−1). These improvements in defect suppression and carrier mobility are critical to achieving efficient charge transport and minimizing recombination losses, enabling high-efficiency solar-to-electricity conversion.

For real-world applications and commercialization, the universality of the post-treatment across different perovskite compositions and the yield of high-efficiency devices must be considered. The PCE histograms based on 20 devices per condition are shown in Fig. 5g. The control group exhibited a lower average PCE with a broader distribution, indicating poor reproducibility. In contrast, the SrI2/IPA SSQ-treated devices demonstrated narrower PCE distributions, with ~90% of devices falling between 19.5% and 21.0%, reflecting excellent uniformity and reproducibility. Supplementary Fig. 27 presents detailed photovoltaic parameter distributions, revealing higher and more consistent JSC, FF, and PCE in the quenched group. To further verify the versatility of the SSQ strategy, we applied it to a variety of blade-coated WBG perovskite films. As shown in Supplementary Fig. 28 and Supplementary Table 5, the blade-coated small-area WBG devices with bandgaps of 1.65 eV (FA0.8Cs0.2Pb(I0.85Br0.15)3) and 1.78 eV (FA0.8Cs0.2Pb(I0.6Br0.4)3) achieved champion PCEs of 22.03% (JSC = 22.47 mA cm−2, VOC = 1.20 V, FF = 81.49%) and 18.66% (JSC = 17.74 mA cm−2, VOC = 1.29 V, FF = 81.40%), respectively. EQE measurements confirmed the band gaps of 1.65 and 1.78 eV for the respective perovskite compositions (Supplementary Fig. 29). Notably, regardless of composition, the SrI2/IPA SSQ-treated devices consistently outperformed controls in both FF and PCE, with narrower performance distributions (Supplementary Fig. 30). The method also proved effective for small-bandgap, MA-free perovskite compositions. PSCs based on SrI2/IPA SSQ-treated FA0.95Cs0.05PbI3 perovskite films delivered a PCE of 21.16% along with an impressive FF of 83% (Supplementary Fig. 31), validating the compositional universality of this approach.

Device operational stability was assessed under ISOS-L-1 protocols. Encapsulated devices were exposed to continuous one sun illumination at the MPP under ambient conditions (25°C ± 5°C, 50% ± 5% RH). As shown in Fig. 5h, control devices showed a quick PCE drop, which only retained <70% of their initial PCEs after 550 h. Encouragingly, the devices fabricated with SrI2/IPA SSQ post-treatment maintained over 95% of their initial PCEs after 1000 h. The time at which the PCE is projected to drop to 80% of its initial value (TPCE80) is extrapolated to be 25,205 h for the target device using an appropriate linear function fitting of the experimental operational stability data in Fig. 5h (Supplementary Fig. 32)64–66. This substantial improvement in stability can be attributed to the synergistic effects of the solution-quenching process, which includes chemical modification, lattice reconstruction, and defect passivation. The halide salts–assisted SSQ treatment simultaneously modulated both the surface and bulk of perovskite films. Surface halide compensation and Sr2+ incorporation passivated defects and optimized energy-level alignment, while the rapid quenching promote surface reconstruction and halide distribution throughout the bulk, relieving residual stress and stabilizing the crystal lattice. These synergistic effects collectively improved device efficiency and intrinsic stability under operational conditions.

Perovskite solar modules for real-world applications

Benefiting from our successful resolution of the key challenge in achieving uniform post-treatment of large-area WBG perovskite films, we systematically evaluated the effectiveness of the SSQ strategy in enhancing WBG perovskite solar modules (PSMs). We fabricated 5.2 cm × 6.0 cm WBG PSMs, and their J-V curves were shown in Fig. 6a. The fabrication workflow, which included all functional layer deposition and laser scribing steps, was illustrated in Supplementary Fig. 33, alongside an optical microscopy image of the P1, P2, and P3 scribing channels, which enabled effective series interconnection between subcells. Each subcell was optimized to a width of 6.7 mm, and by limiting the dead-zone width to 370 µm, we achieved a high geometric FF (GFF) of ~95%. The inset in Fig. 6a shows a schematic of the four subcells connected in series, and a photo of the 5.2 × 6.0 cm2 module was provided in Supplementary Fig. 34. As shown in Fig. 6a, the ~10.4 cm2 (aperture-area) 1.68 eV WBG PSM demonstrated a PCE of 19.79% under reverse scan (JSC = 4.94 mA cm−2, VOC = 4.98 V, FF = 80.44%) and 19.29% under forward scan (JSC = 4.90 mA cm−2, VOC = 4.92 V, FF = 80.03%), indicating negligible hysteresis (Table 2 and Supplementary Fig. 35). The reduced hysteresis in SSQ-treated modules can be attributed to the improved quality of perovskite films with enhanced crystallinity and less defects, as well as favorable halide homogenization and stabilization, which is beneficial to suppression migration under operational bias. The SrI2/IPA SSQ-treated PSMs exhibited an average PCE of 18.72% ± 0.50%, significantly outperforming both the control and the SrI2/IPA SC-treated counterparts. Encouragingly, the 1.68 eV WBG mini-module exhibited a certified PCE of 18.42% under reverse scan, with a VOC of 4.85 V, a JSC of 4.89 mA cm−2, and an FF of 77.72% (Supplementary Fig. 36), confirming the reliability of our reported device performance. This enhancement was also accompanied by a narrower PCE distribution, indicating improved reproducibility and consistently higher values of FF, VOC, and JSC in the quenched group (Fig. 6b and Supplementary Fig. 37). Notably, over 69% of SSQ-treated PSMs achieved PCEs above 18.5%, compared to only 31% of the control devices demonstrated PCEs exceeding 13.5%. These results underscored the efficacy of the SSQ treatment in reliably boosting the photovoltaic performance of PSMs. It was worth pointing out a corresponding active-area (~10.13 cm2) efficiency of 20.32% was achieved, and the performance gap compared to the 0.04 cm2 small-area cells (21.39% PCE) was only 1.07%, representing the smallest reported efficiency loss during upscaling of ~1.68 eV WBG perovskites using blade-coating (Supplementary Table 6). This highlighted the substantial potential of the SSQ strategy for scalable and manufacturable WBG perovskite photovoltaics. As previously mentioned, upscaling typically increases RS, severely impacting the device FF. For example, in the control group, FF decreased from 72.00% in small-area cells to 69.95% in modules. RS in these control PSMs reached 17.45 Ω. In contrast, after the SSQ treatment, RS significantly dropped by 62.64% to 6.52 Ω, enabling the modules to achieve an FF as high as 80.44%, comparable to that of the small-area devices (FF = 81.26%). A systematic analysis and modeling of the relationship between RS and FF in WBG PSMs revealed that SSQ-treated devices markedly deviated from the expected linear trend, exhibiting a greater FF enhancement than predicted for a given decrease in RS (Supplementary Fig. 38). This improvement is attributed to a combined reduction in interfacial resistance at the perovskite/charge transport layer interfaces and the intrinsic bulk resistance of the perovskite film.

Thermal stability tests were conducted under the ISOS-D-2I protocol in an inert N2 atmosphere at 65°C ± 5°C with encapsulation. As shown in Fig. 6c, the MA-free WBG PSMs treated with SrI2/IPA SSQ retained 87% of their initial PCEs after 550 h, compared to only 43% PCE retention for the control group, confirming their strong potential for outdoor deployment. Overall, the SrI2/IPA SSQ strategy enabled comprehensive optimization of both the bulk and surface properties of WBG perovskite films. By stabilizing halide ions, homogenizing the film surface, suppressing lattice distortion, passivating crystallographic imperfections, and improving carrier kinetics, this method significantly enhanced device efficiency, light/moisture/thermal stability, and reproducibility. These improvements translate to promising applications in portable charging devices, building-integrated photovoltaics (BIPV), agrivoltaics, and high-performance tandem photovoltaics.

To demonstrate real-world applicability, we designed integrated photovoltaic scenarios targeting both architectural and agricultural use. For building-integrated photovoltaics, we developed a smart, dual-mode four-terminal tandem solar window that combines a 1.78 eV WBG subcell with a 1.22 eV narrow-bandgap (NBG) subcell, capable of dynamically switching between transparent and opaque modes (Fig. 6d). This system adapted to varying lighting needs: under illumination-demanding conditions (translucent mode), the semi-transparent 1.78 eV WBG single-junction device operated independently, achieving a PCE of 17.22% while maintaining visible light transmittance. When shading was preferred (energy harvesting mode), the device automatically switched to a four-terminal tandem configuration, enabling synergistic utilization of both visible and near-infrared spectra, and delivering a significantly higher PCE of 27.12% (Fig. 6d, Supplementary Fig. 39 and Supplementary Table 7). Notably, the NBG subcell achieved an efficiency of 23.15%, and even under filtered light from the WBG top cell, it retained a PCE of 9.90% (Fig. 6e and Supplementary Fig. 40), which is critical for efficient tandem operation. This demonstration confirmed the potential of the SSQ strategy for realizing high-performance tandem perovskite photovoltaics and established a new paradigm for adaptive photovoltaic systems that balanced indoor comfort with on-demand energy generation in building applications. In addition, we further demonstrated the suitability of the optimized WBG PSMs for powering low-energy indoor electronics. A 5.2 × 6.0 cm2 (8.5 g) WBG PSM was capable of directly powering a miniature fan (Fig. 6f) or integrated to portable power bank for charging a smartphone (Fig. 6g and Supplementary Movie 1), representing practical use cases in office or outdoor environments. For agricultural applications, we fabricated a 1.68 eV WBG semi-transparent PSM modified using the SrI2/IPA SSQ strategy (Fig. 6h). This module exhibited an AVT of 17.55%, with a high transmittance of 28% in the red and far-red spectral range (620–760 nm) that was essential for promoting photosynthesis. Moreover, it achieved a bifacial equivalent efficiency (ηeq) of 18.41% with a bifaciality factor of 51.15% (Supplementary Table 8, Supplementary Figs. 41 and 42). The module was also capable of powering small-scale agricultural machinery (Fig. 6i). Collectively, these results demonstrated that the WBG PSMs developed here could effectively meet the dual demands of energy generation and optimized light conditions for plant growth in smart agricultural environments.

Methods
Materials
ITO-coated glasses, cesium iodide (CsI, 99.998%), lead bromide (PbBr2, 99.99%), and bathocuproine (BCP, 99%) were purchased from Advanced Election Technology Co., Ltd. Lead iodide (PbI2, 99.999%) was purchased from Alfa Aesar. Formamidinium iodide (FAI, 99.99%) and methylammonium iodide (MAI, 99.99%) were purchased from Greatcell Solar Limited (Australia). Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA, 99%), lead sulfocyanide (Pb(SCN)2, 99.5%), PEDOT:PSS (Clevios VPAI 4083), and C60 (99%) were purchased from Xi’an Polymer Light Technology Corp. [2-(9H-Carbazol-9-yl)ethyl] phosphonic acid (2-PACz) and ethylenediamine dihydroiodide (EDAI2, >99%) were purchased from TCI Shanghai. Strontium iodide (SrI2, 99.99%), tin iodide (SnI2, 99.99%), tin(II) fluoride (SnF2, 99%), ammonium thiocyanate (NH4SCN, 99.99%), isopropanol (IPA, 99.8%), chlorobenzene (CB, 99.8%), N,N-dimethylformamide (DMF, 99.8%) and dimethyl sulfoxide (DMSO, 99.8%) were purchased from Sigma-Aldrich. Copper (Cu, 99.99%) and silver (Ag, 99.99%) were purchased from ZhongNuo Advanced Material Beijing Technology Co., Ltd. Unless stated otherwise, all materials were used as received without further purification.

Precursor preparation
Wide-bandgap FA0.8Cs0.2Pb(I1-xBrx)3 perovskite precursor preparation. The FA0.8Cs0.2Pb(I1-xBrx)3 (x=0.15, 0.2, 0.4) perovskite precursor solution (1.5 M) was prepared by dissolving 1.2 mmol FAI, 0.3 mmol CsI, 1.5(1–1.5x) mmol PbI2 and 2.25x mmol PbBr2 in 1 ml mixed solvent of DMF and DMSO with a volume ratio of 7:3. Then 9.69 mg Pb(SCN)2 was added into the solution as additives. The perovskite precursor solution was thoroughly mixed and aged for 2 h before using. Then the solutions were filtered through polytetrafluoroethylene (PTFE) syringe filters (0.45 μm) before use.

Small-bandgap FA0.95Cs0.05PbI3 perovskite precursor preparation. 1.5 M FA0.95Cs0.05PbI3 perovskite precursor was prepared by dissolving 1.35 mmol FAI, 1.65 mmol PbI2, and 0.15 mmol CsI in 1 ml mixed solvent of DMF and DMSO with a volume ratio of 4:1. The precursor was stirred for over 2 h and then filtered by using a 0.45 μm PTFE syringe filter before use.

Narrow-bandgap Sn-Pb perovskite precursor preparation. 46.8 mg CsI, 414.9 mg PbI2, 14.1 mg SnF2, 85.8 mg MAI, 185.7 mg FAI, 335.3 mg SnI2, and 2.7 mg NH4SCN were dissolved in 1 mL mixed solvent of DMF and DMSO with a volume ratio of 3:1. The precursor was stirred for 10 h at 50°C. The solution was shaken to be dissolved in the glove box.

Device fabrication
Fabrication of small-area PSCs. The indium-doped tin oxide (ITO) glass substrates were ultrasonically cleaned by deionized water, IPA, and acetone sequentially, and dried in an oven. The substrates were then subjected to UV-ozone treatment for 15 min and transferred to a glove box for device preparation.

Fabrication of hole transport layer and WBG FA0.8Cs0.2Pb(I1-xBrx)3 (1.65 eV, 1.68 eV, and 1.78 eV) and small-bandgap FA0.95Cs0.05PbI3 perovskite films. For the HTL layer, 50 μL of the PTAA/CB solution (5 mg mL−1) was spin-coated on UV-ozone plasma-treated ITO glass substrate at 6000 rpm for 30 s, followed by annealing at 100°C for 10 min. After cooling down to room temperature, 50 μL of the 2-PACz/DMF solution (10 mg mL−1) was spin-coated onto the ITO/PTAA substrate at 3000 rpm for 30 s and annealed at 100°C for 5 min to improve its wettability67. The perovskite precursors were blade-coated at a blade speed of 5 mm s−1 with a gap of 100 μm, and 10 μL of perovskite ink was used for each coating. During blade-coating, an N2 flow below 20 psi was applied to facilitate the solvent evaporation and perovskite crystallization. Then, the as-prepared perovskite films were transferred onto a hotplate and annealed at 105°C, verified by an infrared thermometer (Supplementary Fig. 43). After 10 min, the perovskite film at 105°C was immediately soaked into SrI2/IPA solution (0.2 mg mL−1) for 5 s, which was cooled to 5°C in advance as the quenching liquid. The quenching speed was estimated to be 20°C s−1. After that, the perovskite film was tempered at 105°C to complete the quenching treatment. Finally, 20 nm C60, 7 nm BCP, and 80 nm Ag were sequentially deposited on the perovskite films via thermal evaporation (Suzhou Fangsheng FS-450) to complete the devices.

Fabrication of hole transport layer and NBG Cs0.1FA0.6MA0.3Sn0.5Pb0.5I3 perovskite films. The PEDOT:PSS aqueous solution was spun onto the substrates at 4000 rpm for 30 s, then annealed at 150°C for 20 min. The Sn-Pb alloying perovskite films were deposited via a two-step spin-coating process, namely, 1000 rpm for 10 s and then 4000 rpm for 40 s, respectively. 200 μL of CB was poured on the spinning substrate after reaching 4000 rpm for 25 s. The substrates were immediately annealed at 120°C for 10 min. The perovskite films were prepared in a glove box filled with an inert nitrogen atmosphere (O2 <0.01 ppm, H2O <0.01 ppm) to carefully prevent Sn2+ oxidation. Finally, 30 nm C60, 5 nm BCP, and 150 nm Cu electrode were sequentially deposited via thermal evaporation. For the completed PSCs, they were either protected in an inert atmosphere or with appropriate encapsulation during testing and characterization.

Fabrication of PSMs. The fabrication process of the PSMs was similar to that of small-area devices except for the dosage of the precursor and the laser scribing patterning process. The schematic of fabrication procedures, including all deposition and scribing steps are as follows (Supplementary Fig. 33). With an aperture area of 10.4 cm2, the module’s layout was designed as a monolithic interconnection of four subcells, each with a 0.67 cm width. Firstly, the ITO-coated glass was etched by a laser scribing process with a 532 nm wavelength laser, yielding a P1 line width of 27 μm. The deposition of all functional layers followed the procedures used for small-area cells, but with adjusted solution quantities, namely, 500 µL for HTL deposition and 20 µL for perovskite layer blade-coating. P2 scribing was performed after the deposition of the perovskite/C60/BCP layers to scribe a line width of 120 μm. After Ag deposition, P3 was performed to scribe a line width of 59 μm, achieving the geometrical fill factor (GFF) of up to 95% for the modules, exhibiting an active area of 10.13 cm2.

Characterization
Steady-state and temperature-dependent photoluminescence (PL) spectra were obtained by FLS1000 (Edinburgh Instruments Ltd.), equipped with a Xe lamp, a liquid nitrogen cryostat (Oxford Instruments, Optis-tat DN-V), and a photomultiplier tube (PMT) detector. The excitation wavelength was 470 nm. PL mapping measurements were conducted using Morpho PG2000-PRO. The morphological features of the samples were characterized using a field emission scanning electron microscope (SEM, Hitachi-SU8010) that executed at 2 kV. The atomic force microscopy (AFM) measurements were performed on a Scanning Probe Microscope (Bruker Dimension Fastscan, Bruker, Germany). The XRD patterns were characterized on an X-ray powder diffractometer with Cu Kα radiation of 1.5418 Å (Rigaku, Japan). Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) measurements were carried out using a ToF-SIMS 5, ION-TOF GmbH. In situ PL measurements under light stress were performed using a mercury lamp light source (OLYMPUS, U-HGLGPS), which provided 130 W output in the 460–490 nm range. GIWAXS images were collected using a Xeuss 2.0 spectrometer (Xenocs company) with MetalJet-D2 (Excillum) as the X-ray source and Pilatus 3R 1M (Dectris) as the detector. Glancing incident angle X-ray diffraction (GIXRD) was performed on a D8-discover 25 diffractometer (Bruker). Valence band (VB) measurements were performed via UPS, employing a bias of 5 V and Au as a reference. Illumination intensity-dependent photoluminescence quantum yield (PLQY) measurements were conducted using the LuminQY system (Ideaoptics). The femtosecond transient absorption (fs-TA) spectroscopy was conducted by equipping a regeneratively amplified Ti:Sapphire laser source (Coherent Legend, 800 nm, 150 fs, 5 μJ mpulse−1, and 1 kHz repetition rate) and Helios (Ultrafast Systems LLC) spectrometers. A 75% portion of the 800 nm output pulse was frequency-doubled in a BaBO (BBO) crystal, which could generate 400 nm pump light. Meanwhile, the remaining portion of the output was concentrated into a sapphire window to produce a white light continuum (320–780 nm) probe light. The 400 nm pump beam was generated as part of the 800 nm output pulse from the amplifier, and its power was adjusted by a range of neutral-density filters. The pump beam was focused at the sample with a beam waist of 360 μm; the power intensity was fixed at 14 μJ cm−2 in this experiment. With the aid of the mechanical chopper, the pump repetition frequency was synchronized to 500 Hz. The probe and reference beams could be split from the white-light continuum and sent into a fiber optics-coupled multichannel spectrometer by complementary metal oxide-semiconductor sensors with a frequency of 1 kHz. The J-V characteristics and the steady photocurrent under maximum power output bias (1.05 V) of PSCs/PSMs were measured in ambient air (25°C ± 5°C and 40% ± 10% relative humidity) using a Keithley 2400 source-meter under simulated AM 1.5G one sun illumination (100 mW cm−2) generated by a solar simulator (the Oriel Sol3A Class AAA) based on Xenon lamps. The light intensity was calibrated by a silicon reference cell equipped with a SCHOTT visible color KG3 glass filter (Newport 91150V). All the devices were tested using non-reflective shadow masks with an aperture area of 0.04 cm2 for the small-area devices and 10.4 cm2 for the large-area PSMs, respectively. The J-V curves were measured from 1.4 V to -0.1 V or from -0.1 V to 1.4 V for the small-area devices, and from 5.5 to -0.1 V or from -0.1 to 5.5 V for the large-area PSMs with a scan rate of 0.1 V s−1. For the space charge limited current (SCLC) test, the J–V characteristics were measured using a CHI Instruments CHI660 electrochemical workstation (ChenHua, China) in a shield box with a structure of ITO/SnO2/perovskite/C60/BCP/Cu. External quantum efficiency (EQE) was measured with the solar quantum efficiency measurement system (SCS10, Zolix Instruments Co., Ltd., China) at wavelength regions from 300 to 850 nm. The optical photo of scribing for subcell separation in modules was conducted by an optical microscope (Olympus BX53MRF-S).

Light stability test. The devices used for the operational stability test were encapsulated by cover glass with edges sealed by butyl tape. The long-term MPP tracking of the encapsulated devices was carried out on the Multi-Channels Solar Cells Stability Test System (Wuhan 91PVK Solar Technology Co. Ltd, China) in ambient air with a relative humidity of 50% ± 5%, following the protocol (ISOS-L-1). The digital source meter (Keithley 2400) was used to record the current density-voltage (J–V) data under AM 1.5G one sun illumination (100 mW cm2).

Thermal stability test. The devices were placed on a heating stage at 65°C ± 5°C in a N2 glove box with encapsulation, following the ISOS-D-2I protocol. The thermal stability assessments were carried out by repeating the J-V characterizations upon heating the devices for different durations.

Statistical analysis
All statistical analysis was performed with Origin 2021. For TA data normalization, the maximum values of the dynamic TA decay lifetime were normalized to 1. To investigate the PCE statistical distribution of small-area PSCs, the histograms of 20 solar cells were used to generate the device performance statistics (Fig. 5g) and calculate the average PCEs with standard deviation (Table 1). To investigate the PCE statistical distribution of large-area PSMs, the histograms of 16 solar modules were used to generate the device performance statistics (Fig. 6b) and calculate the average PCEs with standard deviation (Table 2).

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "It is a pitty that authours did not try tandems in this research after they innovationaly developped a \"quenching\" technology\nfor fabricating large area WB perovskite solar cells. However, this work is still important for those who are working on blade\ncoating based large area perovskite solar cells. Before putting this paper for publication, several issues shuold be\naddressed:\n1. \"quenching\" like technologies have been widely applied for strenghthening materials. An important technical parameter is\nquenching speed. Unforturnately, Authors did not provide \"quenching\" speed details in both experiment and discussion\nsections. Pls make some arguements about \"quenching\" speed.\n2. Quantitative analysis about crystal properties of quenched and non-quenched samples should be provided. E.g., grain\nsize distribution under a relative larger area(tens of um) and phase distribution et.al.\n3. Normally, \"quenching\" will result in a properties changes of materials from surface to inside. Can authors make some\narguements about the influence of halide salts surface treatments on devices photo-electric properties.\n4. Although it has been widely accepted that band gap of perovksite materials has strong relationship with its formula,\nbandgap will change a little with surface conditions. Therefore, it is important to take UPS tests to determine whether band\ngap of some perovskite films are exactly as you claimed, e.g. (FA0.8Cs0.2Pb(I0.85Br0.15)3) and\n(FA0.8Cs0.2Pb(I0.6Br0.4)3) in Fig. S15/Table 3.\n5. Stability is important for PSCs. In this paper, authours take the stability tests under protocol ISOS-D-2I and ISOS-L-1 and\ndeduced devices life time to be 25205h under TPCE80. This is not a experimental results, Pls provide your\nendorsements,e.g. referee or experimental results.", "reviewer_2": "In this work, the authors introduced industrial quenching technology to the field of photovoltaics, marking the first time this\ntechnology has been used to treat large-area perovskite films and improve their optoelectronic performance. A quenching\nmedium based on a cold SrI2/IPA solution was developed for the rapid soaking treatment of hot perovskite films. This\napproach achieved uniform and efficient surface/interface modification of large-area perovskite films at the macroscopic\nscale. Overall, the work is interesting, but a few issues need to be addressed before publication.\nThe SrI2/IPA solution was selected as the medium for the quenching process for a reason. Other solutions should be\nexamined to determine the plausibility of this technology. Please explain the unique advantages of using SrI₂ in this process.\nCurrently, the mechanism by which film quality improves is not clearly linked to the introduced industrial quenching\ntechnology because there is no significant temperature difference between the perovskite film and the solution. This means\nthere is not enough driving force for the second crystallization process.\ngeometric area of perovskite films on substrates, which will be another factor needs to be considered, might be different. So,\na detailed investigation on effect of size of perovskite films should be included. To verify the universality of this method,\nperovskite films of different sizes should be treated using the same method. Similarly, Similarly, the practicality of this\ntechnology should be considered when using different substrate materials to prepare perovskite thin films. In this technology,\nas in quenching treatment, diffusion of thermal energy and interaction between grains are very important. These effects\nimpact the recrystallization process, grain size, and hardness of the perovskite film. The optimized concentration for the\nSrI2/IPA solution at 0.2 mg mL-1 should be carefully given based on more fundamental study. Such as the thickness of the\noptimized layer achieved in this work.\nmethod or specific formula, to help readers gain a clearer understanding.\nwhether the treatment enhances the film's light absorption ability.\nof this significant difference in FF, the authors are suggested to present the characterization with illumination intensity-\ndependent PLQY.\nwork.\n7. There are others for the demonstration of successful SSQ technique with clear and convincing evidences. For example, i)\nthe temperature of the film of the film before the treatment was clearly specified at 105 oC. Is this a specified temperature or a\njust guess. ii) the doping process of Sr2+ in the film, iii) since the blade-coated perovskite film was used as a specific case\n(Figure 1), then there is nothing with coffee-ring as shown in the spin-coating process.", "reviewer_3": "The authors reported an effective post-treatment strategy to address the critical challenge of interfacial non-uniformity that\nhinders the up-scaling of mixed-halide wide-bandgap (WBG) perovskite photovoltaics. By integrating rapid cold/thermal\nshock-driven surface reconstruction and gradient Sr2+ doping conveniently into one-step, the solution soaking quenching\n(SSQ) technique simultaneously realized atomic-level lattice stabilization, surface morphological optimization and\ncompositional homogenization. As a result, the SSQ-derived devices yielded exceptional efficiencies of 22.03% (active\narea: 0.04 cm2) and 20.32% (active area: 10.13 cm2) for 1.68 eV WBG perovskite solar cells and modules, respectively,\ndemonstrating only a small efficiency gap of 1.07% upon device up-scaling. Practical deployment of these optimized WBG\nperovskite solar modules into real-world realms from portable electronics to intelligent photovoltaic glazing (27.12%\nefficiency) are interesting and meaningful. In my opinion, the demonstrated novel processing technique particularly useful for\nthe large-area perovskite solar modules should be beneficial for perovskite researchers in both academic and industrial\nsectors. Thus, I would like to recommend this work to be published in Nature Communications after addressing my following\nconcerns:\n1. Why did the authors select 5°C as the SSQ temperature (\"cooled to 5 °C in advance\" in Methods)? Considering that\ncold/thermal shock and secondary recrystallization kinetics are critically governed by temperature gradients, it is essential to\nverify whether 5 °C represents the optimal condition. The authors are suggested to further compare the photovoltaic\nperformances of devices fabricated via SSQ performed under a different temperature range.\n2. While a quenching medium based on 0.2 mg mL-1 SrI2/IPA solution effectively boosted the photovoltaic performance of\nPSCs, how do other SrI2/IPA concentrations (lower or higher) impact? Supplemental J-V curves for devices with varying\nSrI2/IPA concentrations should be provided to justify the optimal condition.\n3. When analyzing the surface energy levels of the perovskite films using UPS data (Figure 4a and Supplementary Figure\nS11), the authors presented the shift in the Fermi level (EF). However, the manuscript did not explicitly detail the specific\ncalculation procedures used to determine the EF position. To enhance the accuracy and reliability of the data, the authors\nare encouraged to provide a clear description of relevant details.\n4. The authors also demonstrated the versatility of SSQ technique in other WBG devices with bandgaps of 1.65 eV\n(FA0.8Cs0.2Pb(I0.85Br0.15)3) and 1.78 eV (FA0.8Cs0.2Pb(I0.6Br0.4)3) in Supplementary Fig. S15, but the corresponding\nexternal quantum efficiency (EQE) spectra are missing. EQE data is crucial for validating the bandgap of WBG perovskites\nand the exact bandgap could guide their potential applications in real world. It is recommended to provide EQE spectra for\nthese two WBG PSCs and verify the bandgap values via the EQE onset edge.\n5. It is observed that there is hysteresis disparity between spin-coated (SC) and solution-soaking quenching (SSQ)-treated\nmodules (e.g., PCE gap upon reverse and forward scan, Table 2). The authors are suggested to provide the mechanistic\ninsights about this phenomenon.\n6. Several grammatical inconsistencies were noted, such as the sentence, \"Each subcell were optimized to a width of 6.7\nmm\", where \"were\" should be corrected to \"was\". We recommend comprehensive proofreading and checking throughout the\nmanuscript."}, "author_response": "Response to Reviewers’ Comments\nREVIEWER #1\nIt is a pity that authors did not try tandems in this research after they innovatively developed a\n\"quenching\" technology for fabricating large area WB perovskite solar cells. However, this work\nis still important for those who are working on blade coating based large area perovskite solar\ncells. Before putting this paper for publication, several issues should be addressed:\nResponse: We thank the reviewers for the positive endorsement of the novelty and potential\nimpact of our work. Accordingly, we have thoroughly revised the manuscript based on the\nconstructive comments from the reviewer.\nComment #1: \"quenching\" like technologies have been widely applied for strengthening\nmaterials. An important technical parameter is quenching speed. Unfortunately, Authors did not\nprovide \"quenching\" speed details in both experiment and discussion sections. Pls make some\narguments about \"quenching\" speed.\nResponse: We thank the reviewer for pointing this out and providing the constructive\nsuggestions. Accordingly, we have provided the quenching speed details in the Methods section\nof revised manuscript. In the SSQ process, the perovskite film at 105 °C was immediately\nimmersed in the 5°C SrI /IPA quenching liquid for 5 s, which creates a rapid quenching speed\n2\nestimated to be ~20 ℃/s.\nAs can be seen on Page 33, “After 10 min, the perovskite film at 105 °C was immediately\nsoaked into SrI /IPA solution (0.2 mg mL-1) for 5 s, which was cooled to 5 °C in advance as the\n2\nquenching liquid. In this case, the quenching speed was estimated to be 20 °C/s. After that, the\nperovskite film was tempered at 105 °C to complete the quenching treatment.”\nComment #2: Quantitative analysis about crystal properties of quenched and non-quenched\nsamples should be provided. E.g., grain size distribution under a relative larger area (tens of um)\nand phase distribution et.al.”\nResponse: We sincerely thank the reviewer for this valuable suggestion. Accordingly, we further\ninvestigated the grain size distribution for both the control and SSQ-treated perovskite films by\nacquiring and analyzing lower-magnification SEM images over relatively larger area regions of\nseveral micrometers. The results revealed that the average grain size increased from 224.1 nm\nfor the control film to 242.3 nm for the SSQ-treated film, suggesting the effectiveness of SSQ\ntreatment on enlarging the grain sizes of perovskite film. To investigate the phase distribution,\nwe fabricated the control and SSQ-treated large-area perovskite films (5.2 cm × 6.0 cm) and\nmeasuring the XRD patterns on five different regions as indicated. Upon SSQ treatment, similar\nXRD patterns were collected from all 5 regions, which showed the identical characteristic signals\nfor perovskite phase without any detectable secondary phases. This result was in good agreement\nwith the PL intensity mapping results shown in Fig. 1i, unambiguously indicating that the SSQ\ntreatment enabled the formation of uniform and phase-pure perovskite films over a large area,\nwhich is a critical prerequisite for achieving scalable manufacturing and high-performance large-\narea PSCs. We have added the relevant discussion in the revised manuscript.\nAs can be seen on Page 8, “To quantitatively substantiate these morphological and\ncrystallographic improvements, statistical analysis of grain sizes distribution from relatively\nlarger-area regions of SEM images was conducted. As depicted in Supplementary Fig. 4, the\nSSQ-treated perovskite film exhibited more uniform grain size distribution, with the average\ngrain size increasing from 224.1 nm for the control to 242.3 nm. Furthermore, XRD patterns\ncollected from five distinct regions of the large-area (5.2 cm × 6.0 cm) SSQ-treated film showed\nvirtually similar perovskite characteristic peaks without any detectable secondary\nphases/impurities (Supplementary Fig. 5 and 6), demonstrating excellent phase purity and\nuniformity across a large-area dimension. These quantitative data unequivocally confirmed that\nthe SSQ treatment indeed promoted the growth of more uniform and high-quality perovskite\nfilms with enhanced crystalline properties, which underpinned the improved photovoltaic\nperformance.”\nSupplementary Fig. 4. SEM images of the WBG perovskite films fabricated a w/o or b with\nSrI /IPA SSQ treatment. Statistical grain size distribution of the c control and d SSQ-treated\n2\nperovskite films. The histograms are fitted with log-normal functions (solid lines).\nSupplementary Fig. 5. XRD patterns of 5 distinct regions from the large-area (5.2 cm × 6.0 cm)\ncontrol WBG perovskite film as indicated.\nSupplementary Fig. 6. XRD patterns of 5 distinct regions from the large-area (5.2 cm × 6.0 cm)\nSrI /IPA SSQ-treated WBG perovskite film.\nsurface to inside. Can authors make some arguments about the influence of halide salts surface\ntreatments on devices photo-electric properties.\nResponse: We sincerely thank the reviewer for this insightful comment regarding more detailed\narguments about the influence of halide salts-assisted quenching treatment on devices\nphotoelectric properties. Indeed, the SSQ process induced synergistic modifications that\nextended from the surface into the bulk of the perovskite films, thereby collectively\noptimizing the devices’ photoelectric properties through coupled surface passivation and bulk\nmicrostructure regulation. First, on the surface, halide anions from the quenching medium\neffectively compensated for iodine vacancies, leading to effective defect passivation and\nsuppression of non-radiative recombination. Meanwhile, the incorporation of Sr2+ ions at the\nsurface also tuned the energy-level alignment between the perovskite and charge transport layers,\nfacilitating more efficient carrier extraction. In the bulk, the rapid quenching process triggered\nsecondary recrystallization (Fig. 3a-i), optimizing the film morphology (Fig. 1b and c) and\nreleasing residual stress (Fig. 3j-n). During this process, halide ions and a fraction of Sr2+ cations\ncan penetrate deeper into the film, enhancing halide distribution uniformity and stabilizing the\ncrystal lattice. This strong coupling between surface chemistry and bulk structural regulation\nresulted in a simultaneous enhancement of efficiency (increased J , V , FF) and intrinsic\nSC OC\nstability, particularly under light and thermal stress. In summary, the SSQ treatment is not merely\na superficial surface modification, but rather a holistic processing strategy. By employing a\nhalide-rich quenching medium, it enables concurrent surface defect passivation, bulk\nrecrystallization regulation, and lattice stabilization. These integrated effects unlock the full\nphotoelectric potential of the perovskite films, leading to higher efficiency and enhanced\ndurability of the resulting devices. Accordingly, we have made more detailed arguments about\nthe influence of halide salts-assisted SSQ treatment on the devices’ optoelectronic properties.\nAs can be seen on Page 26, “The halide salts–assisted SSQ treatment simultaneously\nmodulated both the surface and bulk of perovskite films. Surface halide compensation and Sr2+\nincorporation passivated defects and optimized energy-level alignment, while the rapid\nquenching promoted secondary recrystallization and halide redistribution throughout the bulk,\nrelieving residual stress and stabilizing the crystal lattice. These synergistic effects collectively\nimproved device efficiency and intrinsic stability under operational conditions.”\nComment #4: Although it has been widely accepted that band gap of perovskite materials has\nstrong relationship with its formula, bandgap will change a little with surface conditions.\nTherefore, it is important to take UPS tests to determine whether band gaps of some perovskite\nfilms are exactly as you claimed, e.g. (FA Cs Pb(I Br ) ) and (FA Cs Pb(I Br ) ) in\n0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nFig. S15/Table 3.\nResponse: We sincerely thank the reviewer for this insightful comment and for highlighting the\nimportance of experimentally verifying the bandgaps of our investigated perovskite films. In the\nrevised manuscript, we determined the bandgaps of (FA Cs Pb(I Br ) ) and\n0.8 0.2 0.85 0.15 3\n(FA Cs Pb(I Br ) ) perovskites by analyzing the onset edge of external quantum efficiency\n0.8 0.2 0.6 0.4 3\n(EQE) spectra for relevant PSCs (Supplementary Fig. 28) (Adv. Mater., 2022, 34, 2108132;\nAdvanced Energy Materials, 2020, 10, 1902573). The results confirmed the optical bandgaps as\n1.65 eV for FA Cs Pb(I Br ) and 1.78 eV for FA Cs Pb(I Br ) , which correctly\n0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nsupported our claimed values in our original manuscript. Relevant discussion has been added in\nthe revised manuscript.\nAs can be seen on Page 25, “EQE measurements confirmed the bandgaps of 1.65 eV and 1.78\neV for the respective perovskite compositions (Supplementary Fig. 28).”\nSupplementary Fig. 28. EQE spectra and the corresponding integrated J values for the control\nSC\nand SrI /IPA SSQ-treated PSCs based on a FA Cs Pb(I Br ) and c FA Cs Pb(I Br )\n2 0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nperovskites. The optical bandgaps determined from the EQE onset are b 1.65 eV for\nFA Cs Pb(I Br ) and d 1.78 eV for FA Cs Pb(I Br ) .\n0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nComment #5: Stability is important for PSCs. In this paper, authors take the stability tests under\nprotocol ISOS-D-2I and ISOS-L-1 and deduced devices lifetime to be 25,205h under T .\nPCE80\nThis is not an experimental result, Pls provide your endorsements, e.g. referee or experimental\nresults.\nResponse: We thank the reviewer for raising this critical point regarding our endorsement of\nextrapolated T lifetimes. The extrapolated T lifetime of 25205 h is derived from fitting\nPCE80 PCE80\nthe operational stability data (i.e. over 95% of their initial PCEs after 1000 h under the ISOS-L-\n1 protocol) using a suitable linear function model, which aligns with common practice in\nestimating the potential operational stability of emerging photovoltaics (Nat. Commun. 2025, 16,\n6438; Nat. Commun. 2025, 16, 8575; Adv. Energy Mater., 2025, 15, 2404538). This fitted model\nwas used to project the time at which the performance would decay to 80% of its initial value\n(T ). As suggested by the reviewer, we have now provided our endorsements about the\nPCE80\nextrapolated T value in the revised manuscript and the relevant figure caption.\nPCE80\nAs can be seen on Page 25, “The time at which the PCE is projected to drop to 80% of its\ninitial value (T ) is extrapolated to be 25205 h for the target device using an appropriate linear\nPCE80\nfunction fitting of the experimental operational stability data in Fig. 5h (Supplementary Fig. 31)\n(Nat. Commun. 2025, 16, 6438; Nat. Commun. 2025, 16, 8575; Adv. Energy Mater., 2025, 15,\n2404538).”\nSupplementary Fig. 31. T evaluation of the operational stability of the SrI /IPA SSQ-\nPCE80 2\ntreated device measured under continuous illumination in ambient air with a relative humidity\nof ~50 ± 5% (red dashed line indicates the extrapolation). Note, the T value is an\nPCE80\nextrapolated lifetime based on the fit to the experimental MPP tracking data in Fig. 5h.\nREVIEWER #2\nIn this work, the authors introduced industrial quenching technology to the field of photovoltaics,\nmarking the first time this technology has been used to treat large-area perovskite films and\nimprove their optoelectronic performance. A quenching medium based on a cold SrI /IPA\n2\nsolution was developed for the rapid soaking treatment of hot perovskite films. This approach\nachieved uniform and efficient surface/interface modification of large-area perovskite films at\nthe macroscopic scale. Overall, the work is interesting, but a few issues need to be addressed\nbefore publication.\nResponse: We highly appreciated the reviewer’s positive endorsement of our work. We have\ncarefully and thoroughly revised the manuscript according to the reviewer’s constructive\ncomments.\nComment #1: The authors innovatively introduced industrial quenching technology into the\nphotovoltaic field. This work is interesting. The SrI /IPA solution was selected as the medium\n2\nfor the quenching process for a reason. Other solutions should be examined to determine the\nplausibility of this technology. Please explain the unique advantages of using SrI in this process.\nindustrial quenching technology because there is no significant temperature difference between\nthe perovskite film and the solution. This means there is not enough driving force for the second\ncrystallization process.\nResponse: We thank the reviewer for the positive feedback on the innovation and potential\nimpact of our work and raising this insightful question regarding the rationale behind the\nselection of SrI as the quenching medium.\ntechnology. In direct response, we have conducted additional experiments using EDAI /IPA, a\n2\nwidely recognized effective post-treatment solution (Nature, 2025, 646, 95-101; Nat. Mater.,\n2025, 24, 252-259), as the quenching medium under the same SSQ conditions. Notably, devices\ntreated with EDAI /IPA also exhibited excellent photovoltaic performance, comparable to our\n2\nchampion devices treated with SrI /IPA SSQ, confirming that the SSQ technique is broadly\n2\napplicable and not limited to a single salt. Nonetheless, SrI provides unique and synergistic\n2\nadvantages. The small ionic radius of Sr2+ allows it to incorporate into the perovskite lattice not\nonly at the surface and grain boundaries, but also progressively penetrate into the bulk during\nthe quenching process, as evidenced by lattice contraction in XRD patterns (Supplementary Fig.\n13) and depth-dependent crystallinity enhancement in GIXRD patterns (Fig. 3a-i). This gradient\ndoping reduces halide vacancies concentration, introduces steric hindrance to suppress ion\nmigration, and subtly adjusts lattice parameters to relieve internal stress (Fig. 3j-n).\nSimultaneously, the Sr2+ incorporation modulates local energy levels, facilitating more favorable\nband alignment and efficient charge extraction. Moreover, Sr2+ could stabilize halide ions,\nmitigate defect-induced lattice distortion, and enhance mechanical robustness and environmental\nresilience of perovskite films. These synergistic effects collectively improve device efficiency\nand operational lifespan of PSCs, particularly under light and thermal stress.\nRegarding the driving force for secondary crystallization, we note that the temperature\ndifference alone is insufficient to explain the observed recrystallization. The film quality\nimprovement arises from a combination of thermodynamic, kinetic, and chemical driving\nforces. As shown in Supplementary Fig. 1, pre-annealing of wet-film at 105 °C drives the initial\nrapid crystallization and forms a metastable, defect-rich perovskite framework with high free\nenergy, providing a thermodynamic impetus for structural evolution. The subsequent quenching\ninto ~5°C SrI /IPA introduces transient thermal stress, partial surface solubilization by IPA, and\n2\na steep chemical potential gradient of Sr2+ and I- across the film-solution interface. These factors\ncollectively promote Sr²⁺ incorporation, halide compensation and passivation, and local mass\ntransport. Finally, the re-annealing (also called “tempering”) step allows sustained solid-state\ndiffusion, enabling deeper Sr2+ penetration and favorable secondary crystallization for improved\nfilm quality, as confirmed by larger grain size (Supplementary Fig. 4), enhanced crystallinity and\nrelieved tensile stress (Fig. 3), and reduced defect density (Fig. 5e and 5f).\nIn summary, the SSQ treatment leverages the inherent instability of the initial film, kinetically\ndriven quenching, and chemical potential guidance from the solution, consolidated by thermal\nannealing, to achieve gradient doping, surface-to-bulk defect passivation, and comprehensive\nsecondary crystallization (Supplementary Fig. 1). While the SSQ platform is versatile\n(demonstrated with EDAI ), SrI is particularly advantageous due to its multi-faceted\n2 2\nstabilization effects at the atomic level, directly addressing key instability pathways in\nperovskites. To clarify these issues, relevant discussion has been added in the revised manuscript.\nAs can be seen on Page 21, “Particularly, the versatility of the SSQ approach is confirmed by\nemploying EDAI /IPA as the quenching medium, which also yielded a high PCE of 20.21%\n2\n(Supplementary Fig. 23), indicating that the SSQ post-treatment is applicable to other salts\nbeyond SrI .”\nactivated by the kinetic shock of quenching, guided by the chemical potential gradient of the\nsolution, and subsequently stabilized through the thermal energy of the final annealing\n“tempering” step, ultimately resulting in gradient doping and comprehensive secondary\ncrystallization (Supplementary Fig. 1).”\nSupplementary Fig. 23. J–V curve and summarized photovoltaic parameters of the 1.68 eV\nWBG PSC based on EDAI /IPA SSQ-treated perovskite film.\nprocess that drives the re-crystallization of perovskite films.\nComment #2: Another consideration in this solution-soaking quenching should be included in\nthis work is that the size effect. The geometric area of perovskite films on substrates, which will\nbe another factor needs to be considered, might be different. So, a detailed investigation on effect\nof size of perovskite films should be included. To verify the universality of this method,\nperovskite films of different sizes should be treated using the same method. Similarly, the\npracticality of this technology should be considered when using different substrate materials to\nprepare perovskite thin films. In this technology, as in quenching treatment, diffusion of thermal\nenergy and interaction between grains are very important. These effects impact the\nrecrystallization process, grain size, and hardness of the perovskite film. The optimized\nconcentration for the SrI /IPA solution at 0.2 mg mL-1 should be carefully given based on more\n2\nfundamental study. Such as the thickness of the optimized layer achieved in this work.\nResponse: We sincerely thank the reviewer for these insightful and constructive suggestions\nregarding the size effect, substrate universality, and concentration optimization of the SSQ\ntechnique. We have carefully conducted additional experiments following these suggestions,\nwhich have significantly strengthened the manuscript and deepened our understanding of SSQ\nmechanism. Our detailed responses are as follows.\n(1) Size effect and scalability:\nFollowing the reviewer's suggestion, we systematically investigated the size effect by applying\nthe SrI /IPA SSQ treatment to perovskite films of different dimensions (1.5 cm × 1.5 cm, 3.5 cm\n2\n× 3.5 cm, and the previously reported 5.2 cm × 6.0 cm (Fig. 1d-i). For all the perovskite films\nwith different dimensions, PL mapping across different regions revealed that both spin-coating\n(SC) and SSQ post-treatment effectively enhanced the PL intensity. One can notice the PL\nintensity of SC-treated films decreased at the edges, as compared to the central region, leading\nto strong spatial nonuniformity. As the film area increased to 5.2 cm × 6.0 cm (13 measurement\nregions), such limitation of the SC approach became more evident. In stark contrast, the SSQ-\ntreated films maintained exceptional PL uniformity across all regions and all film sizes\n(Supplementary Fig. 9 and 10, Fig. 1d-i). These results clearly demonstrated that the advantage\nof the SSQ technique becomes increasingly critical as the device area scales up, addressing the\nscalability challenge highlighted in our work. Relevant discussion has been added in the revised\nmanuscript.\nAs can be seen on Page 9, “To systematically evaluate the scalability of the SSQ strategy, we\nextended the spatial homogeneity analysis to blade-coated WBG perovskite films of different\ndimensions (1.5 cm × 1.5 cm, 3.5 cm × 3.5 cm and 5.2 cm × 6.0 cm) and performed spatially\nresolved photoluminescence (PL) mapping tests on 5, 7 and 13 designated regions, respectively.\nFor the perovskite films of different size dimensions, both SC and SSQ post-treatments\neffectively enhanced the PL intensity. One could notice the PL intensity of SC-treated films\nalways decreased at the edges, as compared to the central region, leading to strong spatial\nnonuniformity, regardless of film areas. As the film area increased to 5.2 cm × 6.0 cm, such\nlimitation of the SC method became more evident. In comparison, the SSQ-treated films\nmaintained exceptional PL uniformity across all regions and all film sizes (Supplementary Fig.\n9 and 10, Fig. 1d-e). Typically, for the largest-area WBG perovskite film (5.2 cm × 6.0 cm) tested\non 13 designated regions, the PL intensity of the central region (Region 7) showed the same\nenhancement trend as the small-area samples (Fig. 1e, Supplementary Fig. 11), with substantially\namplified PL intensity after SrI /IPA post-treatment.”\n2\n(2) Substrate universality:\nTo assess the practicality of the SSQ method on different substrates, we fabricated complete\nPSCs on FTO (fluorine-doped tin oxide) substrates, in addition to the standard ITO ones. As\nshown in the Fig. R1, the champion device on FTO substrate yielded a PCE of 19.68%, inferior\nthan that on ITO. We attribute this primarily to the higher surface roughness (Scientific Reports,\n2023, 13, 16068) and slightly reduced optical transmittance of FTO substrates compared with\nITO substrates (Nature Photonics, 2025, 19, 170-177). Because our blade-coated perovskite\nfilms are relatively thin (~220 nm, Supplementary Fig. 17) for semi-transparent applications, the\nrougher FTO surface likely causes local shunting and incomplete coverage, thereby\ncompromising device performance. It is worth pointing out that the SSQ technique itself is\nsubstrate-independent, while the ultimate device performance depends on substrate quality (i.e.\nroughness, optical transmittance) and charge transport layer compatibility.\n(3) Optimization of SrI concentration:\npreliminary studies, a series of SrI concentrations (0.05, 0.10, 0.20, 0.30 and 0.50 mg/mL) were\n2\ntested. A concentration of 0.20 mg/mL was identified to be optimal, which yielded the best\nbalance between passivation and film uniformity. Lower concentrations led to insufficient\npassivation, whereas higher concentrations caused SrI aggregation and partial precipitation,\n2\ndeteriorating the film morphology and device performance. Corresponding J–V curves and\nstatistical photovoltaic performance data for devices treated with different SrI concentrations\n2\nare now included in the Supplementary Information (Supplementary Fig. 22 and Supplementary\nTable 4). In addition, stylus profile measurements were not accurately enough to distinguish the\nnegligible variation in film thickness (i.e. less than 5-10 nm) across different concentrations of\nSrI /IPA SSQ treatment. We thus concluded that the observed device performance variation was\n2\noriginated from chemical passivation and crystallization modulation, rather than distinct film\nthickness changes. Relevant discussion has been added in the revised manuscript.\nAs can be seen on Page 21, “The SrI /IPA concentration was optimized from 0.05 mg/mL to\n2\n0.50 mg/mL, with 0.20 mg/mL yielding the best device photovoltaic performance\n(Supplementary Fig. 22 and Supplementary Table 4).”\nIn summary, these additional experiments comprehensively confirm the scalability, substrate\ncompatibility, and concentration optimization of the SSQ process, further validating its\npracticality and robustness for large-area perovskite film fabrication.\nSupplementary Fig. 9. a Blade-coated perovskite film (1.5 cm × 1.5 cm) divided into 5 distinct\nregions. b Normalized PL intensity of different locations of small-area WBG perovskite films\n(1.5 cm × 1.5 cm). c Bright-field microscopy and confocal PL mappings of the d control, e\nSrI /IPA SC-, and f SrI /IPA SSQ-treated perovskite films across 5 designated regions.\n2 2\nSupplementary Fig. 10. a Blade-coated perovskite film (3.5 cm × 3.5 cm) divided into 7 distinct\nregions. b Normalized PL intensity of different locations of large-area WBG perovskite films\n(3.5 cm × 3.5 cm). c Bright-field microscopy and confocal PL mappings of the d control, e\nSrI /IPA SC- and f SrI /IPA SSQ-treated perovskite films across 7 designated regions.\n2 2\nFig. R1. J–V curves of the SrI /IPA SSQ-treated 1.68 eV WBG PSCs fabricated at different\n2\nsubstrates.\nSupplementary Fig. 22. J–V curves of the WBG PSCs fabricated via SrI /IPA SSQ post-\n2\ntreatment with different concentrations of SrI /IPA solutions which were cooled to 5 ℃ as the\n2\nquenching liquids.\nSupplementary Table 4. Photovoltaic parameters of the WBG PSCs fabricated via SrI /IPA SSQ\n2\npost-treatment with different concentrations of SrI /IPA solutions which were cooled to 5 ℃ as\n2\nthe quenching liquids.\nV J FF PCE\nOC SC\nConcentrations\n(V) (mA cm-2) (%) (%)\n0.05 mg/mL 1.19 20.92 77.29 19.17\n0.10 mg/mL 1.20 21.32 80.64 20.57\n0.20 mg/mL 1.21 21.68 81.26 21.39\n0.30 mg/mL 1.20 21.31 80.68 20.70\n0.50 mg/mL 1.20 20.89 79.27 19.83\nComment #3: The authors should provide a detailed explanation of the calculation process used\nto obtain Figure 4g, including the fitting method or specific formula, to help readers gain a clearer\nunderstanding.\nResponse: We thank the reviewer for providing the constructive suggestions. Accordingly, we\nhave provided a detailed explanation of the calculation process used to obtain Figure 4g. The\ndecay kinetics of the ground-state bleaching (GSB) signal in our transient absorption (TA) data\nwere analyzed using a widely adopted bi-exponential decay model (J. Am. Chem. Soc. 2014, 136,\n3760–3763), which is well-suited for describing carrier dynamics in perovskite-based devices\nwhere multiple charge extraction and/or recombination pathways coexist. The formula used for\nthe fitting is:\nt t\nI(t) = A exp(- )+A exp(- )+I\n1 2 0\nτ1 τ2\nwhere I(t) is the normalized GSB intensity at specific delay time (t). A and A are the amplitudes\n1 2\nof the fast and slow decay components, respectively. τ and τ are the time constants for the fast\n1 2\nand slow decay processes, respectively. I is a constant offset accounting for any long-lived signal\n0\nthat does not decay within our measured time window. While the bi-exponential model provides\ntwo distinct time constants, it is common practice to report an amplitude-weighted average\nlifetime (τ ) for a more concise and physically meaningful comparison between samples (J. Am.\navg\nChem. Soc. 2020, 142, 4464–4471). This was calculated using the following formula:\nτ =\nA1τ1 2+A2τ2 2\navg\nA1τ1+A2τ2\nIn our work, the values of A , τ , A and τ obtained from the bi-exponential fit for both samples\n1 1 2 2\nare summarized in the Supplementary Table 1. As a result, the calculated τ for the control\navg\ndevice was 779.2 ps, while for the SrI /IPA SSQ-treated device, it significantly decreased to\n2\n303.3 ps. As suggested, we have provided the fitting details in the revised manuscript:\nAs can be seen on Page 20, “The decay kinetics of GSB were analyzed via bi-exponential\nfitting according to the equation:\nτ =\nA1τ1 2+A2τ2 2\n(2)\navg\nA1τ1+A2τ2\nwhere A and A are the amplitudes of the fast and slow decay components, respectively. τ and\n1 2 1\nτ represent the time constants for fast and slow decay components, respectively (J. Am. Chem.\nComment #4: The authors should provide the UV-vis absorption spectrum results for the SrI /IPA\nabsorption ability.\nResponse: We thank the reviewer for this insightful suggestion. Following your advice, we have\nperformed UV-vis absorption measurements on both the control and SrI /IPA SSQ-treated\n2\nperovskite films. The results clearly demonstrated that the SSQ treatment indeed remarkably\nenhanced the light absorption capability of the perovskite film (Supplementary Fig. 18), which\ncan be attributed to the improved film quality with optimized morphology and enhanced\ncrystallinity (Fig. 1a-c and Fig. 3a-i). Relevant discussion has been added in the revised\nmanuscript.\nAs can be seen on Page 15, “The optimized morphology and enhanced crystallinity achieved\nby the SSQ treatment are expected to directly benefit the optoelectronic properties of the\nperovskite films. As shown in Supplementary Fig. 18, the SSQ-treated film exhibited\nsignificantly stronger light absorption capability than that of the control film, establishing a solid\nfoundation for generating higher photocurrent in the complete PSCs (will be discussed in the\nfollowing section).”\nSupplementary Fig. 18. UV-vis absorption spectra of control, SrI /IPA SC-treated and SrI /IPA\n2 2\nSSQ-treated WBG perovskite films.\nComment #5: The PSCs treated with SrI /IPA SSQ showed a significant increase in FF compared\n2\nto the control. To analyze the sources of this significant difference in FF, the authors are\nsuggested to present the characterization with illumination intensity-dependent PLQY.\nResponse: We sincerely thank the reviewer for the insightful comment and valuable suggestion.\nTo further elucidate the origin of the significantly enhanced FF in SrI /IPA SSQ-treated PSCs,\n2\nwe performed illumination intensity-dependent photoluminescence quantum yield (PLQY)\nmeasurements (from 0.001 to 2 suns) and conducted a detailed analysis, as recommended.\nAs shown in Supplementary Fig. 25a, the SrI /IPA SSQ-treated perovskite film exhibited a\n2\nsteeper increase in PLQY with illumination intensity and consistently higher absolute PLQY\nvalues than the control, demonstrating a more effective suppression of non-radiative\nrecombination. Based on the PLQY data, the corresponding QFLS and diode ideality factors (n )\nid\nwere derived (Supplementary Fig. 25b). The SrI /IPA SSQ-treated film exhibited a lower ideality\n2\nfactor (1.38) compared to the control (1.41), suggesting that recombination dynamics approach\nthe radiative limit and trap-assisted losses are effectively reduced (Nat. Commun., 2025, 16, 9435;\nAdv. Mater. 2020, 32, 2000080).\nIn addition to suppressing non-radiative recombination, the enhanced FF also arose from the\nimproved intrinsic film quality induced by the SSQ process and Sr2+ incorporation, which\nfacilitated secondary recrystallization and favorable electrical doping, resulting in higher\ncrystallinity, enhanced carrier mobility, reduced defect densities and more uniform halide\ndistribution. Meanwhile, the Sr2+ incorporation fine-tuned the perovskite energy levels,\nimproving band alignment with the charge transport layers and thus promoting more efficient\ncharge extraction and reducing device’s series resistance. These synergistic effects, including\ndefect passivation, enhanced crystallinity, improved conductivity, and optimized interfacial\nenergetics, collectively accounted for the substantial increase in FF.\nIn summary, illumination intensity–dependent PLQY characterization and other\ncomplementary structural evidence together demonstrated that the SrI /IPA SSQ treatment\n2\nsimultaneously optimized both the charge recombination kinetics and the structural–energetic\nquality of the perovskite films, leading to superior J–V characteristics, especially the remarkably\nenhanced FF. The new data and discussion have been incorporated into the revised manuscript\n(Supplementary Fig. 25).\nAs can be seen on Page 23, “To probe the origin of the FF enhancement, illumination\nintensity-dependent photoluminescence quantum yield (PLQY) measurements and quasi-Fermi\nlevel splitting (QFLS) analyses (from 0.001 to 2 suns) were performed. The SrI /IPA SSQ-treated\n2\nfilm exhibited a steeper increase in PLQY, consistently higher absolute PLQY values across all\nmeasured illumination intensities, and lower ideality factor (n ) (i.e. 1.38 vs. 1.41 for the control),\nid\ndemonstrating suppressed defect-assisted non-radiative recombination and more ideal diode\nbehavior (Nat. Commun., 2025, 16, 9435; Adv. Mater. 2020, 32, 2000080). We concluded that\nreduced non-radiative recombination, together with both improved film quality and optimized\nenergy-level alignment, collectively contributing to the significantly improved FF.”\nSupplementary Fig. 25. a Illumination intensity-dependent PLQY and b QFLS of the control\nand SrI /IPA SSQ-treated WBG perovskite films. The solid lines in (b) represent linear fits of\nid\nComment #6: All the photovoltaic device presented in this study needs to be certified, special\nthose with large area as claimed in this work.\nResponse: We appreciate the reviewer’s valuable suggestion. To verify the reliability of our\nreported device performance, we have commissioned an independent third-party certification for\nthe representative 1.68 eV WBG mini-module, which is the main focus of our study and achieved\nthe most significant efficiency advancement. The certification was conducted by the South\nChina National Center of Metrology Guangdong Institute of Metrology.\nAs shown in Supplementary Fig. 35, the certified mini-module delivered a PCE of 18.42%\nunder reverse scan, with a V of 4.85 V, an J of 4.89 mA cm-2, and an FF of 77.72%.\nOC SC\nThis\ncertified value falls well within the distribution range of our laboratory-tested devices (average\nPCE: 18.72 ± 0.50%) and is close to our reported champion efficiency (19.78%), thereby\nconfirming the reliability and reproducibility of our reported photovoltaic performance.\nIt is worth noting that each certification of a single device entails substantial cost (several\nthousand RMB yuan per test) and time. Due to limited research funding, we prioritized\ncertification for the 1.68 eV WBG module, which represents the most technologically relevant\nand performance-optimized system in this work. Nonetheless, multiple laboratory-tested devices\nhave demonstrated consistent performance, reinforcing the validity of the reported efficiencies.\nAs can be seen on Page 26, “Encouragingly, the 1.68 eV WBG mini-module exhibited a\ncertified PCE of 18.42% under reverse scan, with a V of 4.85 V, a J of 4.89 mA cm-2, and an\nOC SC\nFF of 77.72% (Supplementary Fig. 35), confirming the reliability of our reported device\nperformance.”\nSupplementary Fig. 35. Certification report of the SrI /IPA SSQ-treated 1.68 eV WBG\n2\nperovskite mini-module with an aperture area of 10.4 cm2 issued by South China National Center\nof Metrology Guangdong Institute of Metrology.\nComment #7: There are others for the demonstration of successful SSQ technique with clear and\nconvincing evidences. For example, i) the temperature of the film before the treatment was\nclearly specified at 105 °C. Is this a specified temperature or a just guess, ii) the doping process\nof Sr2+ in the film, iii) since the blade-coated perovskite film was used as a specific case (Figure\n1), then there is nothing with coffee-ring as shown in the spin-coating process.\nResponse: We sincerely thank the reviewer for this insightful comment and for emphasizing the\nimportance of providing clear and convincing experimental evidence to support the proposed\nSSQ mechanism. In response, we have conducted additional experiments and substantially\nstrengthened the mechanistic validation in our revised manuscript. The detailed responses are as\nfollows:\ni) Film temperature before quenching\nWe appreciated the reviewer’s careful observation regarding the precise temperature of the\nperovskite film prior to quenching. The temperature of 105 °C was not an estimated value but\nthe set temperature of the hotplate used during pre-annealing. To rigorously verify that the film\nitself reached this temperature, we directly measured the temperature of a large-area perovskite\nfilm on the hotplate using an infrared thermometer under identical annealing conditions. As\nshown in Supplementary Fig. 42, the surface temperature of the film uniformly reached 105 °C,\ndemonstrating excellent agreement with the hotplate set-point. This confirmed the accuracy and\nreliability of our reported experimental conditions. Relevant discussion has been added in the\nrevised manuscript.\nAs can be seen on Page 33, “Then, the as-prepared perovskite films were transferred onto a\nhotplate and annealed at 105 °C, verified by an infrared thermometer (Supplementary Fig. 42).”\nii) Sr2+ doping process during quenching and tempering\nWe fully agree with the reviewer that elucidating the Sr2+ doping process is crucial to\nunderstand the SSQ mechanism. To directly probe this, we performed time-resolved\nphotoluminescence (PL) measurements from both the front (quenched side) and rear (glass\nside) of the films after quenching, followed by tempering annealing for varying durations (0-120\ns). At 0 s (quenching only, without tempering), the front-side PL intensity increased, while\nthe rear-side PL showed negligible change, indicating that Sr2+ incorporation and defect\npassivation were initially confined to the surface region. As the tempering time increased,\nthe rear-side PL intensity gradually rose and eventually saturated after 100 s, following the front-\nside saturation (~80 s). This distinct temporal evolution provides direct experimental evidence\nthat Sr2+ doping and associated defect passivation proceed progressively from the surface into\nthe bulk of the film during the tempering step, driven by solid-state ion diffusion. This process\nis schematically illustrated in the Supplementary Fig. 13 and discussed in the main text of revised\nmanuscript.\nAs can be seen on Page 11, “To unravel the kinetics of Sr2+ incorporation, we monitored the\nevolution of passivation by measuring the PL intensity from both the front and rear sides of the\nfilm after quenching and during subsequent tempering (Supplementary Fig. 13). The front-side\nPL intensity increased immediately after quenching, and saturated after 80 s, indicating rapid\nsurface passivation. In contrast, the rear-side PL intensity remained low without tempering and\nincreased gradually upon annealing, saturating after ~100 s. This delay demonstrated that Sr2+\ndoping occurred via a time-dependent, solid-state diffusion process during tempering,\nenabling the passivating species to propagate from the surface into the bulk, thereby\nachieving comprehensive film improvement.”\niii) Clarification on the “coffee-ring” effect and its relevance\nWe thank the reviewer for this valuable comment, which allows us to clarify a key aspect of\nour innovation. There seems to be a misunderstanding that we would like to address respectfully.\nThe coffee-ring effect we discuss is not associated with our blade-coated perovskite film\nitself, but rather with the conventional spin-coating post-treatment process that our SSQ\ntechnique aims to replace. In traditional post-treatments, spin-coating often causes non-uniform\nsolute distribution due to Marangoni convention and differential solvent evaporation, resulting\nin well-known “coffee-ring” phenomenon. While this may be acceptable for small-area films, it\nleads to serious inhomogeneity in large-area modules. In contrast, our SSQ technique completely\ncircumvents this issue by immersing the entire film into the quenching solution, thereby\neliminating the convective flows-induced coffee-ring effect and non-uniformities. This ensures\na homogeneous and isotropic supply of SrI across the entire film surface, guaranteeing uniform\n2\nsurface reconstruction and defect passivation, showing a decisive advantage for scalable\nfabrication. This is precisely the rationale behind developing the SSQ approach, and the uniform\nPL intensity distribution across large-area blade-coated perovskite films, as shown in Fig. 1d-i,\ndirectly validated its effectiveness. We have revised the manuscript to make this distinction and\nthe associated advantage of our SSQ method explicitly.\nAs can be seen on Page 9, “This limitation originates from Marangoni convection during the\nconventional spin-coated post-treatment, where differential solvent evaporation rates on the wet-\nfilm surface creates radial temperature and concentration gradients, leading to solute\naccumulation at the droplet edges (\"coffee-ring\" effect). Such inhomogeneous deposition hinders\nuniform surface reconstruction and induces localized chemical heterogeneity. This effect\nbecomes more pronounced as the film area increases, causing discontinuities in carrier transport\nchannels and large interfacial charge transport barriers. In contrast, our SSQ technique\ncompletely circumvents this issue by immersing the entire film into the quenching solution,\nthereby eliminating the convective flows-induced coffee-ring effect and non-uniformities. This\nensures a homogeneous and isotropic supply of SrI across the entire film surface, guaranteeing\n2\nuniform surface morphology and comprehensive defect passivation, showing a decisive\nadvantage for scalability.”\nSupplementary Fig. 42. Surface temperature of large-area perovskite films detected using an\ninfrared thermometer.\nSupplementary Fig. 13. PL intensity evolution of the a front and b rear side of perovskite films\nafter SrI /IPA SSQ treatment, followed by tempering annealing for varying durations.\nThe authors reported an effective post-treatment strategy to address the critical challenge of\ninterfacial non-uniformity that hinders the up-scaling of mixed-halide wide-bandgap (WBG)\nperovskite photovoltaics. By integrating rapid cold/thermal shock-driven surface reconstruction\nand gradient Sr2+ doping conveniently into one-step, the solution soaking quenching (SSQ)\ntechnique simultaneously realized atomic-level lattice stabilization, surface morphological\noptimization and compositional homogenization. As a result, the SSQ-derived devices yielded\nexceptional efficiencies of 22.03% (active area: 0.04 cm2) and 20.32% (active area: 10.13 cm2)\nfor 1.68 eV WBG perovskite solar cells and modules, respectively, demonstrating only a small\nefficiency gap of 1.07% upon device up-scaling. Practical deployment of these optimized WBG\nperovskite solar modules into real-world realms from portable electronics to intelligent\nphotovoltaic glazing (27.12% efficiency) are interesting and meaningful. In my opinion, the\ndemonstrated novel processing technique particularly useful for the large-area perovskite solar\nmodules should be beneficial for perovskite researchers in both academic and industrial sectors.\nThus, I would like to recommend this work to be published in Nature Communications after\naddressing my following concerns:\nResponse: We thank the reviewer’s positive recognition of our work. Accordingly, we have\ncarefully considered the reviewer’s comments and thoroughly revised the manuscript.\nComment #1: Why did the authors select 5 °C as the SSQ temperature (\"cooled to 5 °C in\nadvance\" in Methods)? Considering that cold/thermal shock and secondary recrystallization\nkinetics are critically governed by temperature gradients, it is essential to verify whether 5 °C\nrepresents the optimal condition. The authors are suggested to further compare the photovoltaic\nperformances of devices fabricated via SSQ performed under a different temperature range.\nResponse: We sincerely thank the reviewer for raising this critical point. Accordingly, we have\ncompared the photovoltaic performances of PSCs fabricated via SSQ performed under a different\ntemperature range at 0 °C, 5 °C, 10 °C, and 20 °C. The results clearly showed that devices via\nSSQ performed at 5 °C exhibited the highest PCE and FF (Supplementary Fig. 21. and\nSupplementary Table 3). Accordingly, we have added relevant discussion in the revised\nmanuscript.\nAs can be seen on Page 21, “Notably, SSQ treatment performed at 5 °C helped to realize the\noptimal device photovoltaic performance (Supplementary Fig. 21 and Supplementary Table 3),\nwhich can be attributed to sufficient cold-thermal shock to drive favorable secondary\nrecrystallization.”\nSupplementary Fig. 21. J–V curves of the WBG PSCs fabricated via SrI /IPA SSQ post-\n2\ntreatment with the SrI /IPA solution (0.2 mg mL-1) cooling to different temperatures as the\n2\nquenching liquid.\nSupplementary Table 3. Photovoltaic parameters of the WBG PSCs fabricated via SrI /IPA SSQ\n2\npost-treatment with the SrI /IPA solution (0.2 mg mL-1) cooling to different temperatures as the\n2\nquenching liquid.\nV J FF PCE\nOC SC\nTemperatures\n(V) (mA cm-2) (%) (%)\n0 ℃ 1.19 21.13 78.56 19.77\n5 ℃ 1.21 21.68 81.26 21.39\n10 ℃ 1.20 21.23 79.70 20.41\n20 ℃ 1.18 21.01 77.36 19.21\nComment #2: While a quenching medium based on 0.2 mg mL-1 SrI /IPA solution effectively\n2\nboosted the photovoltaic performance of PSCs, how do other SrI /IPA concentrations (lower or\n2\nhigher) impact? Supplemental J–V curves for devices with varying SrI /IPA concentrations\n2\nshould be provided to justify the optimal condition.\nResponse: We thank the reviewer for raising this critical point. Accordingly, we investigated and\ncompared the photovoltaic performance of PSCs fabricated via SSQ based on different SrI /IPA\n2\nconcentrations ranging from 0.05 mg/mL to 0.50 mg/mL. As a result, a concentration of 0.20\nmg/mL was identified to be optimal (Supplementary Fig. 22. and Supplementary Table 4).\nRelevant discussion has been added in the revised manuscript.\nAs can be seen on Page 21, “The SrI /IPA concentration was optimized from 0.05 mg/mL to\n2\n0.50 mg/mL, with 0.20 mg/mL yielding the best device photovoltaic performance\n(Supplementary Fig. 222 and Supplementary Table 4).”\nSupplementary Fig. 22. J–V curves of the WBG PSCs fabricated via SrI /IPA SSQ post-\n2\ntreatment with different concentrations of SrI /IPA solutions which were cooled to 5 ℃ as the\n2\nquenching liquids.\nSupplementary Table 4. Photovoltaic parameters of the WBG PSCs fabricated via SrI /IPA SSQ\n2\npost-treatment with different concentrations of SrI /IPA solutions which were cooled to 5 ℃ as\n2\nthe quenching liquids.\nV J FF PCE\nOC SC\nConcentrations\n(V) (mA cm-2) (%) (%)\n0.05 mg/mL 1.19 20.92 77.29 19.17\n0.10 mg/mL 1.20 21.32 80.64 20.57\n0.20 mg/mL 1.21 21.68 81.26 21.39\n0.30 mg/mL 1.20 21.31 80.68 20.70\n0.50 mg/mL 1.20 20.89 79.27 19.83\nComment #3: When analyzing the surface energy levels of the perovskite films using UPS data\n(Figure 4a and Supplementary Fig. 19), the authors presented the shift in the Fermi level (E ).\nF\nHowever, the manuscript did not explicitly detail the specific calculation procedures used to\ndetermine the E position. To enhance the accuracy and reliability of the data, the authors are\nF\nencouraged to provide a clear description of relevant details.\nResponse: We thank the reviewer for raising this important point regarding the clarity of our\nUPS data analysis. In response to the comment, we have now provided a detailed description of\nthe calculation procedure for determining the Fermi level (E ) position in the revised manuscript.\nF\nAs can be seen on Page 18, “By calculating the energy difference between the incident He I\nphoton energy (21.22 eV) and the binding energy corresponding to the secondary electron cut-\noff edge as shown in Supplementary Fig. 19, the Fermi level (E ) of the perovskite films can be\nF\ncalculated.”\nComment #4: The authors also demonstrated the versatility of SSQ technique in other WBG\ndevices with bandgaps of 1.65 eV (FA Cs Pb(I Br ) ) and 1.78 eV (FA Cs Pb(I Br ) )\n0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nin Supplementary Fig. 27, but the corresponding external quantum efficiency (EQE) spectra are\nmissing. EQE data is crucial for validating the bandgap of WBG perovskites and the exact\nbandgap could guide their potential applications in real world. It is recommended to provide\nEQE spectra for these two WBG PSCs and verify the bandgap values via the EQE onset edge.\nResponse: We thank the reviewer for this constructive suggestion. As recommended, we have\nperformed external quantum efficiency (EQE) measurements for those two WBG PSCs based\non FA Cs Pb(I Br ) and FA Cs Pb(I Br ) perovskites fabricated without or with\n0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nSSQ treatment (Supplementary Fig. 28). The corresponding bandgap (Eg) values of those two\nWBG perovskites were determined from the Tauc plot analysis derived from the EQE onset edge,\nwhich verified the E values were 1.65 eV for FA Cs Pb(I Br ) and 1.78 eV for\ng 0.8 0.2 0.85 0.15 3\nFA Cs Pb(I Br ) , respectively. Relevant discussion has been added in the revised\n0.8 0.2 0.6 0.4 3\nmanuscript.\nAs can be seen on Page 25, “EQE measurements confirmed the bandgaps of 1.65 eV and 1.78\neV for the respective perovskite compositions (Supplementary Fig. 28).”\nSupplementary Fig. 28. EQE spectra and the corresponding integrated J values for the control\nSC\nand SrI /IPA SSQ-treated PSCs based on a FA Cs Pb(I Br ) and b FA Cs Pb(I Br )\n2 0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nperovskites. The optical bandgaps determined from the EQE onset are c 1.65 eV for\nFA Cs Pb(I Br ) and d 1.78 eV for FA Cs Pb(I Br ) .\n0.8 0.2 0.85 0.15 3 0.8 0.2 0.6 0.4 3\nComment #5: It is observed that there is hysteresis disparity between spin-coated (SC) and\nsolution-soaking quenching (SSQ)-treated modules (e.g., PCE gap upon reverse and forward\nscan, Table 2). The authors are suggested to provide the mechanistic insights about this\nphenomenon.\nResponse: We thank the reviewer for this insightful observation and constructive tips.\nUndesirable ion migration has been widely observed and reported in perovskites and has been\nregarded as one of the main origins responsible for anomalous J–V hysteresis and inferior\nstability in the perovskite solar cells. (Nat. Commun., 2016, 7, 10334; Nat. Mater., 2015, 14,\n193–198). We attributed the reduced hysteresis in SSQ-treated modules primarily to the\nformation of improved quality perovskite films with enhanced crystallinity and less defects, as\nwell as suppressed halide phase separation owing to the Sr2+-assisted halide homogenization and\nstabilization. Relevant discussion has been added in the revised manuscript.\nAs can be seen on Page 26, “The reduced hysteresis in SSQ-treated modules can be attributed\nto the improved quality of perovskite films with enhanced crystallinity and less defects, as well\nas favorable halide homogenization and stabilization, which is beneficial to suppress ion\nmigration under operational bias.”\nComment #6: Several grammatical inconsistencies were noted, such as the sentence, \"Each\nsubcell were optimized to a width of 6.7 mm\", where \"were\" should be corrected to \"was\". We\nrecommend comprehensive proofreading and checking throughout the manuscript.\nResponse: We thank the reviewer for pointing this out. We have checked and revised the\nmanuscript carefully. All grammatical mistakes have been corrected, for instance, as can be seen\non Page 26 and 35.\nAs can be seen on Page 26, “Each subcell was optimized to a width of 6.7 mm, and by limiting\nthe dead-zone width to 370 µm, we achieved a high geometric FF (GFF) of ~95%.”\nAs can be seen on Page 35, “PSCs/PSMs were measured in ambient air (25 °C ± 5 ℃ and 40%\n± 10% relative humidity) using a Keithley 2400 source-meter under simulated AM1.5G one sun\nillumination.”\nResponse to Reviewers’ Comments\nREVIEWER #2\nThe authors have made substantial revisions in response to the reviewers' comments, which have\nfurther improved the overall quality of the manuscript. However, there are several issues that\nstill require clarification or revision.\nResponse: We sincerely thank the reviewers for the thorough evaluation and constructive\nsuggestions, which have prompted us to perform additional experiments and refine our\ninterpretations. Accordingly, we have conducted new characterizations to directly probe the\niodine compensation mechanism and have revised the manuscript to more accurately describe\nthe structural evolution induced by the SSQ treatment. Our detailed responses are as follows.\nComment #1: Firstly, the assertion that \"the rapid quenching promoted secondary\nrecrystallization and halide redistribution throughout the bulk, relieving residual stress and\nstabilizing the crystal lattice\" is not substantiated by the present study's experimental findings,\nwhich do not provide sufficient evidence to support the proposed iodine compensation\nmechanism. In particular, no direct characterization is presented to demonstrate how the SrI /IPA\n2\nsolution quenching treatment compensates for iodine vacancies. The provision of additional\nexperimental data and analyses is encouraged to provide substantiation for this claim.\nResponse: We appreciate the reviewer’s emphasis on providing direct experimental evidence for\nthe proposed iodine compensation mechanism. In response, we performed X-ray photoelectron\nspectroscopy (XPS) measurements on both control and SrI /IPA SSQ-treated perovskite films to\n2\nanalyze the surface halide compositions. The XPS results revealed an obvious increase in the\nsurface I/Pb atomic ratio from 2.07 for the control film to 2.26 for the SSQ-treated film, which\nwas much closer to the ideal stoichiometric ratio (~2.4). Even when accounting for potential\npartial substitution of Pb2+ by the incorporated Sr2+ (Sr/Pb= ~0.5%), the adjusted I/(Pb+Sr) ratio\nstill reaches ~2.24, which remains substantially higher than that of the control counterpart. These\nXPS data provide direct evidence that the SrI /IPA quenching medium supplies additional halide\n2\nions (I-) that could be incorporated into the perovskite lattice, thus effectively compensating for\niodine vacancies and improving the intrinsic stability of resultant perovskite films (J. Am. Chem.\nSoc., 2020, 3989-3996; ACS Nano, 2025, 42826-42834). We have added these new data and\ncorresponding discussion in the revised manuscript.\nAs can be seen on Page 12, “To directly probe the surface chemical modification and iodine\nvacancy compensation induced by the SSQ treatment, we performed X-ray photoelectron\nspectroscopy (XPS) on both control and SrI /IPA SSQ-treated perovskite films, providing\n2\nquantitative information on surface I/Pb atomic ratios. Survey XPS spectra for these two samples\nwere shown in Supplementary Fig. 13a. For the mixed-halide FA Cs Pb(I Br ) perovskite\n0.8 0.2 0.8 0.2 3\ncompositions, the theoretical I/Pb ratio is 2.4. However, the average I/Pb ratio measured on the\nsurface of the control perovskite film was only 2.07, revealing a pronounced iodine-deficient\nsurface characteristic. After SrI /IPA SSQ treatment, the surface I/Pb ratio exhibited a remarkable\n2\nincrease to 2.26 (Supplementary Fig. 13b). Even considering the potential partial substitution of\nPb2+ by Sr2+, the adjusted I/(Pb+Sr) ratio still reached ~2.24, which remained substantially higher\nthan that of the control film. This unambiguously demonstrated that the SSQ treatment\neffectively mitigated surface iodine loss by supplying additional iodide ions from the quenching\nmedium, thereby filling undesirable iodine vacancies.”\nSupplementary Fig. 13. a Survey XPS spectra of the control and SrI /IPA SSQ-treated\n2\nperovskite films. b Relative I/Pb ratio at the surface of control and SrI /IPA SSQ-treated\n2\nperovskite films calculated from the XPS measurements.\nComment #2: Moreover, the evidence supporting the occurrence of \"secondary recrystallization\"\nremains insufficient. It is a well-established fact that recrystallization in perovskite thin films is\ngenerally associated with pronounced grain boundary migration and a significant increase in\ngrain size. However, these characteristics were not observed in the present study. Instead, the\nexperimental results appear to be more consistent with surface reconstruction or localized\nstructural reorganization of the perovskite films. In view of these findings, it is recommended\nthat the authors reconsider the application of the term \"secondary recrystallization\" in this\ncontext, or alternatively, furnish more substantial evidence to substantiate its occurrence.\nResponse: We thank the reviewer for this insightful suggestion, which has helped us to describe\nthe SSQ mechanism more accurately. We agree with the reviewer that the term “secondary\nrecrystallization” may imply extensive grain boundary migration and dramatic grain growth with\nenlarged size, which were not the predominant features observed in our films. Instead, the\nstructural improvements induced by SSQ are more accurately described as “surface\nreconstruction” coupled with lattice reorganization and stress relief. In light of this, we have\nrevised the relevant descriptions throughout the manuscript to replace “secondary\nrecrystallization” with more precise terms such as “surface reconstruction” or “localized\nstructural reorganization”.\nAs can be seen on Page 2, “The cold/hot shock-driven surface reconstruction process\nenhanced film crystallinity...”\nAs can be seen on Page 5, “This cold and hot shock-driven surface reconstruction strategy...”\nAs can be seen on Page 7, “...ultimately resulting in gradient doping and comprehensive\nsurface reconstruction (Supplementary Fig. 1).”\nAs can be seen on Page 8, “...passivation molecule-assisted surface reconstruction caused\nby the cool-thermal shock.”\nAs can be seen on Page 10, “...passivation ions-assisted surface reconstruction and localized\nstructural reorganization.”\nAs can be seen on Page 14, “..., indicating a robust crystal structure reinforced by surface\nreconstruction and structural rearrangement.” and “SSQ-mediated surface reconstruction\nand residual stress mitigation”.\nAs can be seen on Page 15, “Conversely, the SrI /IPA SSQ approach enabled solution-\n2\nmediated surface reconstruction and structural reorganization...”\nAs can be seen on Page 16, “SSQ-assisted surface reconstruction and lattice strain\nmodulation.”\nAs can be seen on Page 18, “This stress relief was attributed to surface reconstruction and\nlattice reorganization...” and “...relieving residual stress through compositional engineering\n(Sr2+ doping and halide compensation) and surface reconstruction.\nAs can be seen on Page 23, “..., which can be attributed to sufficient cold-thermal shock to\ndrive favorable surface reconstruction.”\nAs can be seen on Page 26, “..., while the rapid quenching promoted surface reconstruction\nand halide redistribution throughout the bulk, relieving residual stress and stabilizing the crystal\nlattice.”"}, {"round": 2, "reviewer_comments": {"reviewer_1": "Personally, I believe this paper can be published. I have no other comments.", "reviewer_2": "The authors have made substantial revisions in response to the reviewers' comments, which have further improved the\noverall quality of the manuscript. However, there are several issues that still require clarification or revision.\nFirstly, the assertion that \"the rapid quenching promoted secondary recrystallization and halide redistribution throughout the\nbulk, relieving residual stress and stabilizing the crystal lattice\" is not substantiated by the present study's experimental\nfindings, which do not provide sufficient evidence to support the proposed iodine compensation mechanism. In particular, no\ndirect characterization is presented to demonstrate how the SrI2/IPA solution quenching treatment compensates for iodine\nvacancies. The provision of additional experimental data and analyses is encouraged to provide substantiation for this\nclaim.\nMoreover, the evidence supporting the occurrence of \"secondary recrystallization\" remains insufficient. It is a well-\nestablished fact that recrystallization in perovskite thin films is generally associated with pronounced grain boundary\nmigration and a significant increase in grain size. However, these characteristics were not observed in the present study.\nInstead, the experimental results appear to be more consistent with surface reconstruction or localized structural\nreorganization of the perovskite films. In view of these findings, it is recommended that the authors reconsider the application\nof the term \"secondary recrystallization\" in this context, or alternatively, furnish more substantial evidence to substantiate its\noccurrence.", "reviewer_3": "The authors have addressed all my concerns, can be published as it is. Congrats to all authors!"}, "author_response": ""}, {"round": 3, "reviewer_comments": {"reviewer_2": "I have no further comments."}, "author_response": ""}]

Decision letter