Regulating perovskite crystallization kinetics at laser scribe lines for efficient and stable perovskite modules

Domain: physics
Published: 2026-02-20
Editorial outcome: major_revision

Abstract
The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has approached that of silicon-based counterparts, yet their limited long-term stability remains a critical obstacle to commercialization. In this study, laser scribing is identified as a crucial factor affecting the stability of perovskite solar modules (PSMs), as evidenced by the differing degradation rates observed between PSMs and PSCs. Detailed characterization reveals that the P1 scribe areas exhibit poor crystalline quality and accelerated degradation, primarily due to mismatched crystallization kinetics. Furthermore, the P2 and P3 scribing processes induce localized thermal damage, resulting in material decomposition that further undermines module stability. Therefore, we propose a strategy for regulation of perovskite crystallization kinetics by (E)-But-2-ene-1,4-diaminedihydrochloride, which promotes high-quality, preferentially oriented perovskite films to enhance their environmental tolerance. As a result, PSMs with aperture areas of 25 cm² and 100 cm² achieve impressive efficiencies of 24.70% and 23.89%, respectively. Notably, the 100 cm² PSM attains a certified record efficiency of 23.55%. Furthermore, unencapsulated PSMs retain 93% of their initial PCE after 3,120 hours of storage in ambient air (~15% RH), following the ISOS-D-1 standard. This work provides a module-level perspective for advancing the understanding and improvement of long-term stability in perovskite photovoltaics.

Introduction
Organic-inorganic hybrid perovskite has recently become one of the most impressive semiconductor materials attributed to the high absorption coefficient, long carrier diffusion length and tunable bandgap1–5. Currently, the champion power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been boosted to 26.95%6. However, when the device area is scaled up to the module size, significant efficiency losses are still observed7,8. The highest certified efficiency for perovskite solar module (PSMs, over 100 cm2) to date is 22.46%9. The best PSMs can only work stably for thousands of hours10–14, which still lags far behind that of silicon solar modules (10~30 years) and significantly hinders the commercialization process15.

The degradation of PSCs is typically attributed to the deterioration of the perovskite, primarily driven by defects in the perovskite film16. These defects, such as halide vacancies11,17,18, excess lead iodide (PbI2)19,20, surface and interfacial voids14,21–23, significantly compromise the performance of PSCs. To reduce defect content of perovskite film, many efforts have been devoted from aspects of crystal regulation, interface passivation as well as post-treatment upon the laboratory scale PSCs (<1 cm2)14,24–28. However, many of the strategies are difficult to really apply with the quality enhancement of large-area perovskite films. Furthermore, many issues that would not be encountered with small-area PSCs arise in the preparation of the large-area modules7,29–31. Therefore, the module perspective should be established to understand the performance issues of the large-area PSMs.

In fact, the efficiency and stability of modules is significantly inferior to that of small-area PSCs with similar structures. This is mainly due to the serial interconnection of multiple sub-cells in the module, which relies on laser scribing for the P1, P2, and P3 lines32. Laser scribing causes some specific instability issues in large-area PSMs7,33. For instance, thermal diffusion during P2 scribing can degrade the perovskite layer. The residual of the transport layer due to incomplete P2 scribing, which causes current shunting34–36. The degradation of the perovskite layer is accelerated by the diffusion of metal electrodes and halogens in the P2 scribe area. And also, oxygen and water molecules erode the P3 scribe area37. For P2 and P3 scribing, in addition to interdiffusion between the electrode layer and the perovskite active layer, thermal damage during the etching process is also a key factor contributing to the rapid aging of modules38–40. Previous research has largely focused on constructing buffer layers and mitigating thermal damage41–43. However, studies have also shown that perovskite crystals of inferior quality tend to degrade more rapidly under various environmental stresses44,45, placing higher demands on the crystallization conditions of the substrate30,46. Previous studies on gas-liquid nucleation within slit pores have demonstrated that nucleation dynamics in confined geometries differ significantly from those on planar surfaces47,48. These studies suggest that enhancing the crystallinity of the entire perovskite film, including the P1 scribe regions, contributes to improved environmental tolerance of the film, thereby boosting the overall stability of the module.

In this work, it is revealed that laser scribing is a critical factor influencing the efficiency and stability of PSMs, evidenced by differing degradation rates between PSMs and PSCs. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) mapping characterizations demonstrate that the scribe lines (P1, P2, P3) induce distinct degradation mechanisms. The perovskite films around the P1 scribe area reveal poor crystalline quality and accelerated degradation, caused by substrate depression and altered roughness due to P1 scribing. P2 and P3 scribing processes introduce thermal damage that decomposes the perovskite, collectively exacerbating local degradation and impairing module stability. To enhance the quality and environmental tolerance of the perovskite film, we introduce (E)-But-2-ene-1,4-diaminedihydrochloride (BDECl) into the perovskite precursor solution, enabling bottom-up quasi-epitaxial growth of α-FAPbI3 with preferred orientation and enhanced film quality. The resulting PSMs achieve efficiencies of 24.70% (25 cm²) and 23.89% (100 cm²). Notably, the corresponding 25 cm² PSMs retain 94% of the initial PCE after 1200 h of maximum power point (MPP) tracking under continuous illumination in N2. Moreover, the stability of these unencapsulated PSMs (with an aperture area of 25 cm2) maintains 93% of their original PCE values after 3120 h in ambient air (~15% RH), following ISOS-D-1 standards.

Results
Degradation Site of PSMs in the scribe area
Formamidine-based (FA) perovskites are widely used in high-efficiency PSCs due to their excellent photoelectric performance, ideal bandgap, and superior thermal stability. In this study, in order to avoid the instability factor brought by the hole transport layer (Spiro-OMeTAD), we use ion-modulated (IM) radical doped Spiro-OMeTAD instead of conventional doped Spiro-OMeTAD49. The PSMs are fabricated with a n-i-p structure of glass/indium tin oxide (ITO)/tin oxide (SnO2)/perovskite (FAPbI3)/2,2′,7,7′-tetrakis[N,N- bis(p-methoxyphenyl)amino] −9,9′-spirobifluorene (Spiro-OMeTAD)/silver (Ag). Both the transporting layers and perovskite films are prepared with a room-temperature blade-coating method. The etching parameters for nanosecond pulsed laser and femtosecond pulsed laser are presented in Supplementary Note 1-3. The surface morphology of the substrate after etching is shown in Supplementary Fig. 1. Considering that reduce the production cost when preparing fabrication large-area PSMs, nanosecond pulsed laser instead of picosecond and femtosecond lasers is employed.

First of all, the control PSCs and PSMs with different aperture areas (0.102 cm2, 1.01 cm2, 25 cm2, and 100 cm2) are fabricated. The photovoltaic parameters and J-V characteristics of these devices are summarized in Supplementary Table 1 and Supplementary Fig. 2. As shown in Fig. 1a, a PCE loss of 18% (24.35% to 19.98%) for control devices is observed with the increase of aperture area from 0.102 to 100 cm2. By comparing the performance parameters (Supplementary Fig. 3 and Supplementary Note 4), it is noticed that the primary loss arises from a reduction in the fill factor (FF). This is attributed to the decreased crystal uniformity of the perovskite films during the scaling process from small-area to large-area fabrication, leading to increased non-radiative recombination29,50,51. And other factor such as increased series resistance, shunt paths, and contact resistance, can also contribute significantly to FF losses during scaling. Therefore, increasing the FF in the future is an important way to further make up the efficiency loss. Moreover, in Fig. 1b, it is observed that after 3600 h of aging in ambient air with ~15% relative humidity (RH) (ISOS-D-1), the efficiency of PSMs declined to 57% of their initial efficiency. This degradation rate of large-area modules is significantly faster than that of small-area PSCs. Remarkably, all perovskite films of PSMs began to degrade from the scribe area by the photographs (Supplementary Fig. 4).

To explore the degradation mechanisms in the scribe area, the degradation process and thermal damage phenomena are monitored around the three laser scribe lines (P1, P2, and P3) in the perovskite module (Fig. 1c). Firstly, the instability of perovskite films caused by P1 scribing is studied, and then, two hypotheses regarding perovskite layer deposition are proposed (detailed discussion in Supplementary Fig. 5). The morphology of the fresh perovskite film in the P1 scribe area is investigated using scanning electron microscopy (SEM). As shown in Fig. 1d and Supplementary Fig. 6, the SEM images reveal significant accumulation of PbI2 and increased presence of voids on the top and bottom surfaces of the perovskite in the scribe area. Cross-sectional SEM images further show that the scribe depression is not filled with SnO2, leaving voids (10-200 nm) at the bottom of the perovskite layer, indicating poor crystal quality in these areas. Previous studies, such as Huang et al., have demonstrated that voids at the bottom interface of perovskite films can accelerate degradation under light52. These voids, caused by uneven crystallization, could be the underlying cause of the rapid degradation of PSMs.

To further elucidate the scribing-induced degradation mechanisms, attention is turned to the P2 scribe line. As shown in Fig. 1e, the top-view SEM image of the P2 scribe area reveals the presence of residues within the scribed line. Notably, Splashes and solidified rims are visible, indicative of significant localized thermal effects during the laser patterning process. This observation is further supported by cross-sectional SEM images, which show that the perovskite material adjacent to the P2 scribe edge has been altered by the laser-induced heat, resulting in a thin layer of remaining material. This microstructural change confirms the strong thermal influence of the P2 scribing process on the surrounding perovskite film, which will promote further degradation of the perovskite modules38,40,53.

Finally, the P3 scribing step is subsequently investigated to assess its impact on module stability. As depicted in Fig. 1f, the SEM image of the P3 scribe area shows residual material appearing as grains and debris on the trench surface. Furthermore, uneven, streaky patterns are visible along the P3 scribe edges, suggesting film deformation due to heat diffusion. The cross-sectional SEM image provides more critical insight: near the P3 scribe area, the distinct interfaces between the perovskite, Spiro-OMeTAD, and metal electrode layers become indistinguishable. This morphological blurring is attributed to the high laser energy required to ablate the metal electrode, which likely induces intermetallic diffusion between the laser-heated layers and/or promotes reactions with the ambient air environment, such as oxidation-induced material decomposition34,39,54,55. These alterations underline the pronounced thermal and structural impact of P3 scribing, further contributing to the degradation pathways in perovskite solar modules.

Perovskite crystallization mechanism in the P1 scribe area
The impact of perovskite film quality on module stability was further characterized. To analyze the degradation process in the P1 scribe area, the surface morphology and degradation dynamics are characterized by optical microscopy (OM) (Fig. 2a). It clearly shows that a small number of defects are present in the freshly prepared (t0) perovskite film in the P1 scribe area, and the results are consistent with the SEM images (Fig. 1d). After 20 days of aging (t0 + 20 days) in a low-humidity ambient air with ~15% RH, the perovskite in the P1 scribe area is almost completely degraded, and the degraded area starts to spread to the non-scribe area (see Supplementary Fig. 7 for SEM images). Meanwhile, the XRD pattern in Supplementary Fig. 8 is shown the presence of the yellow phase (δ-FAPbI3) and PbI2 in the fresh perovskite film in the P1 scribe area. Interestingly, with aging in a low humidity (~15% RH) ambient air, the δ-phase and the PbI2 signals of perovskite films in the P1 scribe area gradually strengthen, while the α-FAPbI3 signal at 13.9° are gradually weakened. The degradation rate of perovskite films in the P1 scribe area is significantly faster than that in the non-scribe area. The Cross-sectional SEM images in Supplementary Fig. 9 of perovskite module after aging in ambient air with ~15% RH for 20 days are further verified. Additionally, exposure to high-humidity conditions (~70% RH) accelerated the degradation of perovskite films, further confirming the faster degradation rate in the P1 scribe area, which is attributed to the poor film quality in this area (see Supplementary Figs. 10 and 11 for details). Compared with the P1 scribe area, these results show that the non-scribe area exhibits longer photoluminescence lifetime and less carrier non-radiative recombination, reflecting fewer surface defects and superior film quality. The surface morphology of degraded perovskite film is shown in Supplementary Fig. 12. Finally, OM and SEM tracking of the perovskite film degradation around the P1 scribe line under 1-sun illumination shows that the formation of PbI2 and voids is the key factor determining stability in this region (see Supplementary Figs. 13, 14 for details).

To further investigate the crystallization mechanism, SEM images of the films during annealing are presented (Fig. 2b, c, Supplementary Fig. 15a), focusing on the perovskite morphology around the P1 scribe area. First, the annealing process of the perovskite film in the non-scribe area is analyzed in 0-600 s (Fig. 2b). During the blade-coating of perovskite films, the majority fraction, DMF, quickly evaporates to leave the “wet” films under N2 blowing at room temperature. The small fraction of the nonvolatile NMP retarded the crystallization to yield large grains as well as intimate contact with bottom substrates. Initially, the as blade-coated film without annealing (0 s) forms a solid shell at the film top surface. The detailed description of the Grazing incidence x-ray diffraction (GIXRD) measurement in Supplementary Fig. 16 clearly illustrates the top-down crystallization mechanism of the perovskite. After 30 s of annealing at 150 °C, the rate of conversion is fast, nearly converting all of the intermediate phase to perovskite phase, and the films rapidly turn black and become much smoother. Subsequently, the solvent evaporation continues as the annealing time extends from 30 to 300 s, and the perovskite grains become increasingly distinct. With extended annealing duration to 300 to 600 s, a small amount of PbI2 appears at the grain boundaries, likely due to delayed escape of residual NMP from the bulk, accompanied by A-site cation loss from the lead iodide octahedra. Interestingly, studies suggest that films with a slight excess of PbI2 often enhance the quality and efficiency of PSCs56,57, highlighting the potential benefits of this phenomenon.

Then, the morphology of perovskite films in the P1 scribe area is further analyzed with different annealing times, as presented in Fig. 2c. Before thermal annealing (0 s), the surface morphology of the “wet” perovskite film shows almost no difference between the non-scribe and P1 scribe areas. When heating to 150 °C for 30 s, the perovskite film begins to nucleate and crystal growth, with small grains forming on the film’s surface. Top-view SEM images of the P1 scribe area with varying annealing times illustrate the impact of Ostwald ripening during film growth, where the larger particles smaller ones. After annealing for 120 s, the nucleation and growth processes are basically complete, however, a few voids appear at grain boundaries, likely due to residual NMP solvent at the bottom hindering nucleation and promoting the formation of randomly oriented grains with high defect density. Similarly, after 300 s annealing, a small amount of PbI2 appeared on the surface of the perovskite film, likely due to the same cause as in the non-scribe area. However, because of the large amount of residual NMP solvent in the P1 scribe area, the content of PbI2 at the top surface increased significantly after heating for 600 s.

As comparison, the perovskite film exhibits more defects at the edge of P1 scribing and within the P1 scribe area after annealing at 150 °C for 600 s. A significant accumulation of PbI2 is observed at the grain boundaries. In contrast, the high-quality perovskite films in the non-scribe area exhibit homogeneity crystals, and pinhole-free surface morphology. At the same time, the Atomic Force Microscopy (AFM) images (Supplementary Fig. 15b) further illustrate that the perovskite crystals obviously settled into the scribe depression after printing, resulting in the film surface of the P1 scribe area with more defects and a higher roughness (Rq), indicative of poor morphology. In fact, the morphological differences are attributed to distinct crystallization processes in the two areas. In the non-scribe area, the crystallization process is basically complete after 30 s of annealing, with further annealing primarily enhancing grain size and boundary clarity. Conversely, in the P1 scribe area, crystallization is delayed by residual solvent, which slows nucleation and Ostwald ripening. After 120 s of annealing, the crystallization process in the P1 scribe area is complete, accompanying with the formation of holes on the film surface, further highlighting the impact of delayed solvent evaporation on film quality. More importantly, it is found that during the fabrication of large-area PSMs, the depth of depression in the P1 scribe area could not be filled by electron transport layer (ETL), as depicted in Supplementary Fig. 5b. According to our previous investigate of the literature, other studies have largely overlooked the impact of P1 scribing on the perovskite layer8,33, generally assuming that the scribe area would be filled with the ETL or hole transport layer (HTL)7,8,21,30,58–61, which is inconsistent with the phenomenon we found. It is further verified that the P1 scribe area could not be filled with the transport layer by the step profiler (Supplementary Fig. 17a).

The confinement crystallization and substrate differences around the P1 scribe area are identified as critical factors contributing to crystalline differentiation in printed PSMs. First of all, confinement crystallization induced by laser scribing emerges as a key factor affecting the uniformity of perovskite films. To elucidate the structural evolution throughout the entire crystallization process, in-situ GIWAXS experiments are conducted to monitor wet perovskite films during annealing at 150 °C. In the non-scribe area, δ phase of the FAPbI3-based perovskite immediately turns to the α-phase. In a short period of time, both nucleation and crystallization process of the α-phase occurred. In contrast, the wet film of perovskite in the P1 scribe area takes nearly 70 s of annealing time to completely evaporate the solvent and convert the intermediate phase to the α-phase. Compared to the non-scribe area, nucleation growth occurred considerably slower in the P1 scribe area, and the crystal quality is significantly poorer (Fig. 2d, and Supplementary Figs. 18, 19).

To further study the surface morphology and structure of the perovskite in both the non-scribe area and the P1 scribe area via Transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Comparison in Fig. 2e shows that the crystallization of perovskite in the non-scribe area is more consistent, while the lattice structure in the P1 scribe area appear significantly different. The high-resolution HR-TEM images in the non-scribe area clearly indicate well-resolved springs, with a d-spacing value of 3.7 Å of (111) plane confirms the cubic structure of the perovskite (Supplementary Table 2). In addition, the SAED pattern along the [111] zone axis in the upper right corner confirms the presence of cubic α-FAPbI3 (black phase) in the non-scribe area, with additional diffraction spots marked by the circles. In contrast, the SAED pattern along the ½42 (cid:1) 1(cid:2) zone axis suggests that the perovskite film in the P1 scribe area is not cubic α-FAPbI3 but rather hexagonal PbI2. The control perovskite film around the P1 scribe area is characterized using Fourier transform infrared microscopy (Micro-FTIR), as shown in Supplementary Fig. 20. The Two-dimensional IR mapping of perovskite films in the P1 scribed area exhibited characteristic peaks at 1366 cm−1 (Pb-I lattice vibration) and 1712 cm−1 (C=N+ stretching of FA+) with significantly enhanced and attenuated intensities, respectively. This indicates that the content of PbI2 is higher in this area, while the content of FA+ is lower.

Then, the substrate difference caused by P1 etching is also harmful to uniform deposition of perovskite films on the substrate. A crater-shape on the edge of the P1 scribe area is observed by the step profiler, with a ridge height of about 100 nm (Supplementary Fig. 17a). In fact, this is the formation of ridges by the material melts and evaporate at the edge, during the laser scribe process62. Moreover, a part of the ablated material in the P1 scribe area will be redeposited on the transparent electrode, increasing the roughness of the substrate around the P1 scribe area. To evaluate the effect of P1 scribing on surface conditions, the contact angles of water and perovskite precursor solution are measured in both the non-scribe area and the P1 scribe area, respectively. The schematic diagram of the contact angle in the P1 scribe area is shown in Supplementary Fig. 21a, which reveals that the contact angles of both water and perovskite precursor solution are larger in the P1 scribe area compared to the non-scribe area (Supplementary Fig. 21b). This indicates that P1 scribing increases the contact angle, which also means that P1 scribing will lead to the weaker wettability of the substrate surface. Although the contact angles between the non-scribe area and the P1 scribe area of the substrate remained almost the same after plasma treatment (Supplementary Fig. 21c), it is impossible to eliminate the increase in roughness caused by laser etching (Supplementary Fig. 22b). Due to the edge effect on small-area substrates, the uniformity of the perovskite films differs between the ITO/Glass substrates and the bare glass substrates (Supplementary Fig. 22c, d). The perovskite films deposited on smooth ITO/Glass substrates exhibit enhanced crystallinity and reduced defect density. Due to the high roughness and ridge formation at the edge by P1 scribing, there are numerous defects in the nucleation and crystallization process of perovskite films. In addition, we design a customized substrate (with the same laser scribe parameters as before) and conduct experiments on this substrate with SnO2/PVK by blade-coating, respectively. The diagram of laser scribing is shown in Supplementary Fig. 23a. The stability of perovskite is tested by X-ray diffraction (XRD) (Supplementary Fig. 23b) in ambient air, revealing that the degradation of perovskite occurred more rapidly in the P1 scribe area. Therefore, this supports the hypothesis that many crystal defects and poor surface morphology of perovskite are due to the high roughness of the substrate by laser scribing. A comparison of the two sets of XRD diagrams shows that the fresh perovskite in the non-scribe area exhibits a sharper peak shape and narrower half-peak width for black-phase (α-FAPbI3), indicating better crystallization in this area, further corroborating the above views.

Based on this, the crystallization mechanism of perovskite is proposed in the P1 scribe area, displayed in Supplementary Fig. 24. Since the crystallization of perovskite films by using one-step solution deposition method usually starts at the film-air interface as solvents evaporate from the film top surface to form a solid shell. A larger amount of unevaporated NMP solvent remains at the bottom. Then, the residual NMP solvent at the bottom breaks through the solid shell at the top surface from the grain boundary, carrying away a part of the organic cations in the middle of the lead iodide octahedra. This process results in the formation of more voids and lead iodide in the P1 scribe area of the perovskite during crystallization.

This phenomenon is not confined to the regular (n-i-p) structure PSMs, but also occurs in the inverted (p-i-n) structure PSMs (Supplementary Fig. 25a). We attempted to optimize the crystallization of perovskite in the P1 scribe area by adjusting the nanosecond laser parameters for the etching process. While ensuring that the ITO layer is just completely ablated (with the etching depth of ~150 μm), the etching width is changed (Supplementary Fig. 26). However, it was found that increasing the etching width fails to enhance the crystallization of perovskite films in the P1 scribe areas. To exclude the possibility that these results are specific to nanosecond lasers, the experiment is repeated using a femtosecond laser (Supplementary Fig. 17b). This indicates that the electron transport layer remains inadequately fill the depression caused by femtosecond laser scribing. Therefore, the crystallization process of perovskite on the substrate by femtosecond laser scribing is characterized (Supplementary Fig. 27). Compared to the non-scribe area, the surface morphology of perovskite in the P1 scribe area is also poorer (Supplementary Fig. 25b). The crystallization differences between the non-scribe area and the P1 scribed area are further verified using different perovskite precursor solutions (Supplementary Fig. 28). Correspondingly, light-soaking tests on films with these different precursor inks consistently revealed preferential degradation in the P1 scribe area due to its inferior crystallinity (Supplementary Figs. 29–31), mirroring the decomposition process observed in the control film (Supplementary Fig. 14). These findings demonstrate that increased crystallization defects and poorer film quality in the P1 scribe area are consistent issues, regardless of the PSM structure (n-i-p or p-i-n), the laser type (nanosecond or femtosecond), or the type of perovskite precursor ink (FAPbI3, FA0.88Cs0.12PbI3, or FA0.9MA0.05Cs0.05PbI3), underscoring the persistent influence of confinement crystallization and substrate differences.

Thermal damage induced by P2 and P3 laser etching
While the implementation of laser scribing is indispensable for the monolithic interconnection of perovskite solar modules (PSMs), the localized energy input during the P2 and P3 patterning steps introduces significant thermal challenges38–40. The perovskite absorber, along with the charge transport and electrode layers, is inherently sensitive to both heat and light33,54. Therefore, the laser parameters (including wavelength, pulse duration, fluence, and repetition rate) critically determine the extent of thermal load and the resultant material modifications34,38–40,54,55. To understand the degradation pathways associated with laser scribing, a systematic investigation into the thermal damage induced specifically during the P2 and P3 laser etching processes is essential.

The P2 scribe is the most critical in terms of the performance achieved in the interconnected module as it determines to a large extent the series resistance of the module and thus the fill factor63. The P2 scribing process can also damage the adjacent active perovskite layer thereby reducing the performance. First, the morphology of the P2 scribe line and its surrounding regions is analyzed (see Supplementary Fig. 32 for details). The analysis reveals that the perovskite within the P2 scribed region is completely removed, with clear evidence of thermal impact including molten splashes, white particulate deposits, and residual debris along the scribe edges. These features collectively point to significant localized thermal damage during P2 etching, likely contributing to long-term degradation in the module performance.

Building upon the morphological evidence of localized thermal damage, we further investigate its impact on the chemical composition of the perovskite film. The observations from Fig. 1e and Supplementary Fig. 32 suggest that the pulsed laser deposits sufficient energy to induce compositional changes extending beyond the ablated volume. This energy deposition and its subsequent propagation imply a potential alteration of the perovskite composition within the active module area. To examine whether and how the P2 scribing process modifies the perovskite structure, we performed energy-dispersive X-ray spectroscopy (EDS) analysis in the vicinity of the P2 scribe region (Fig. 3a). Due to the high temperatures expected within the laser pulse duration, FAPbI3 may decompose in lead-based products, such as PbI2, PbO, etc. EDS intensity analysis reveals low carbon and high oxygen signals within the P2 scribe area, confirming the complete removal of the perovskite and exposure of the underlying ITO surface. Concurrently, elevated lead and iodine signals inside the scribe trench indicate the presence of residual PbI2 from modified perovskite. Along the P2 scribe edges, a pronounced accumulation of lead is observed, whereas the corresponding iodine signal remains comparatively weak. This discrepancy suggests partial oxidation of the lead during laser ablation, resulting in the formation of lead oxides, which is likely due to interaction with ambient oxygen under high local temperature. To further validate these findings, Micro-FTIR is employed, which corroborated the localized chemical alterations identified by EDS (Supplementary Figs. 33, 34). To further validate these findings, two‑dimensional Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) mapping was employed (Fig. 3b). The thermal damage during laser scribing first induces the escape of volatile FA+; thus, the FA+ signal serves as a sensitive indicator of thermal impact. The FA+ signal weakens progressively closer to the scribe line, where the thermal effect is most severe. Correspondingly, a distinct bright band of FA+ and PbI+ is observed along the scribe edges, which spatially aligns with the thin layer of residual material identified in the cross‑sectional SEM image (Fig. 1e). This correspondence directly links the chemical signature from TOF-SIMS to the microstructural features formed by laser‑induced thermal modification.

Subsequently, photoluminescence (PL) mapping is then performed to spatially resolve the optoelectronic quality of the film surrounding the P2 scribe line (Fig. 3c). The PL intensity distribution clearly shows that the luminescence intensity of the perovskite/Spiro-OMeTAD around the P2 scribe line is enhanced. The enhanced emission is attributed to the accumulation of PbI2, which impedes charge transfer at the perovskite/Spiro-OMeTAD interface around the P2 scribed area. Concurrently, the low PL intensity observed directly around the P2 scribe area of the perovskite film further corroborates the high defect density in this area. This spatial pattern signifies a severe degradation of optoelectronic performance in these regions, directly attributable to the perovskite decomposition induced by thermal damage during the laser scribing process. The suppressed PL emission correlates directly with the thermal and chemical alterations previously identified by SEM, EDS and FTIR, confirming that laser-induced damage profoundly disrupts the local crystallinity and defect landscape of the perovskite film around the scribe line.

Here, OM and SEM are used to characterize the perovskite degradation in the P3 scribe area (Supplementary Figs. 35, 36). The characterization reveal that heat-diffusion-induced film deformation along the scribe edges. Substantial residual debris within the trench indicates incomplete ablation. Thus, the laser energy for P3 scribing was minimized to the extent possible. A one-dimensional thermal decay model further shows the lateral heat spread, with the elevated temperature promoting the decomposition of both the Ag electrode and the adjacent perovskite into silver iodide (AgI) at the surface. These combined observations highlight the pronounced thermal damage and associated material alterations induced by P3 laser scribing. The chemical composition of the prepared P3 line and its surrounding area is then analyzed using EDS (Fig. 3d). Unlike the P2 scribe, EDS analysis of the P3 scribed area revealed no significant lead accumulation. This is attributed to the higher laser energy used in P3 scribing, which promotes vaporization of the perovskite and reduces ridge-related accumulation. However, the increased energy also induces more pronounced thermal damage, as shown in Supplementary Figs. 35, 36 and Fig. 1f. These compositional changes confirm that the P3 scribing process not only removes the metal electrode but also induces significant chemical degradation in the adjacent perovskite, compromising the structural integrity of the film around the P3 scribe region. To further elucidate the chemical alterations, two-dimensional TOF-SIMS mapping of the P3 region was performed (Fig. 3e). In contrast to the P2 scribe, the spatial distribution of FA+ adjacent to the P3 line exhibits a significantly narrower bright band, indicating a more severe depletion of the organic cation due to the stronger thermal impact from the higher laser energy. Concurrently, the presence of Ag2I+ over an extended area around the scribe line signifies that the elevated local temperature promotes the thermal decomposition of both the silver electrode and the adjacent perovskite, leading to the formation of silver iodide (AgI) on the surface. This observation aligns well with the morphological evidence of surface decomposition shown in Supplementary Fig. 35f.

Then, the top silver electrode is peeled off with tape to expose the underlying Spiro-OMeTAD surface (Supplementary Fig. 37), enabling PL mapping to assess the optoelectronic properties of the film adjacent to the P3 scribe line (Fig. 3f). The resulting reveals significantly stronger emission from the perovskite/Spiro-OMeTAD film around the P3 scribed area (the damage area). We attribute this enhanced emission to the disruption of charge‑transfer channels between the perovskite and Spiro‑OMeTAD induced by laser‑thermal damage. To exclude any influence from residual silver electrode on the PL intensity, the fluorescence lifetime in this region was also characterized (inset, Fig. 3f). The observed longer fluorescence lifetime further confirms the impeded charge transfer at the damaged interface. Collectively, the morphological, compositional, and optoelectronic analyses confirm that P3 laser scribing induces severe thermal damage, leading to electrode and perovskite decomposition. These alterations collectively undermine the local charge collection efficiency and accelerate long-term degradation, representing a critical challenge for the monolithic interconnection of perovskite solar modules.

Crystal growth regulation by additive engineering
There are two main pathways for perovskite grain growth: downward homogeneous nucleation and upward heterogeneous nucleation64–68. In homogeneous nucleation, solvent evaporation triggers the nucleation of perovskite grains at the top of the film, which then grow from top to bottom. In contrast, heterogeneous nucleation initiates at the substrate interface, where grains grow upward from the intermediate phase convert to perovskite. Previous experiments have shown that downward homogeneous nucleation leads to increased voids at the bottom and top interfaces, along with PbI2 formation at the grain boundaries. To address this, the perovskite precursor solution must be modulated to achieve the high-quality films. By promoting the bottom-up heterogeneous nucleation, a 2D perovskite intermediate phase is formed at the bottom of perovskite films. This intermediate phase serves as a guiding template for the bottom-up quasi-epitaxial growth during the thermal annealing process, thereby inducing the ordered growth of perovskite films along the bottom template.

The perovskite layer is fabricated by using one-step solution deposition methods (Fig. 4a). To further tune of perovskite fabrication, large-organic cations, with longer lengths or larger ionic radii than that of formamidinium cation (FA+), have been mainly used in forming one dimensional (1D) or two-dimensional (2D) templates24,25,69–71. Therefore, (E)-But-2-ene-1,4-diaminedihydrochloride (BDECl) is introduced to the perovskite precursor solution. Pre-crystallized BDEPbI4 2D perovskite films, prepared with PbI2 in advance, serve as templates and nucleation sites to trigger the α-FAPbI3 phase bottom-up formation, thereby enhancing the crystallinity of perovskite films (Supplementary Fig. 38).

Figure 4b shows the crystallization process of α-FAPbI3 oriented growth. First of all, during the annealing process, the BDEPbI4 intermediate phase preferentially locates at the bottom of the intermediate film. Since the perovskite film is annealed from the glass side, the first-formed bottom orientation template facilitates the bottom-up growth of the subsequent perovskite layer. Then, the 2D perovskite acts as the nucleation site to assist the template grow starting from the bottom. Due to the matched heterointerface between BDEPbI4 perovskite and 3D perovskite, the bottom-up quasi-epitaxial growth of FAPbI3 perovskite is achieved by inheriting the strong orientation of the 2D template. When the [PbI6]4− octahedral assemble on the 2D component, the BDE+ cations replaced by FA+ begin to be extruded gradually from the lattice within the wet film. Subsequent, the deprotonation of BDE+ cations during thermal annealing drives a large number of BDE+ cations to volatilize from the film72. Finally, a highly oriented 3D perovskite with complete α-FAPbI3 phase transition is constructed.

To comprehensively investigate the effect of BDEPbI4 template on the 3D perovskite’s crystallization process, grain orientation, film morphology, and carrier transport, the optimal content of BDECl (0-3 mol%) in the perovskite precursor solution is determined preferentially (Supplementary Fig. 39). The PSCs with the addition of 2 mol% BDECl to the perovskite precursor solution (target) achieve the highest average PCE. Then, to further explore the influence of BDECl on the crystallization of perovskite films by azimuthally integrated in-situ GIWAXS during heating at 150 °C. This indicates that the crystallization orientation is optimized by the addition of BDECl (Fig. 4c, and a detailed description can be found in Supplementary Fig. 40). GIXRD measurement also confirmed this crystallization process, which is described in detail in Supplementary Fig. 41.

Figure 4d and Supplementary Figs. 42, 43 demonstrates a significant improvement in the uniformity of both the top and bottom surfaces of the target film. This method is also effective in fabricating p-i-n structured PSMs, yielding high-quality, pinhole-free perovskite films in the P1 scribe area (Supplementary Fig. 44). The target perovskite film around the P1 scribe area is characterized by Micro-FTIR, as shown in Supplementary Fig. 45. The two-dimensional mapping of the perovskite film revealed almost identical peak intensities at 1366 cm−1 and 1712 cm−1 between the non-scribe area and the P1 scribe area, indicating that the uniformity of the film around the P1 scribe area has been enhanced. Compared to the control film, the defect density of the target film is characterized in the P1 scribe area (Supplementary Fig. 46). Supplementary Fig. 47 shows the fluorescence lifetime imaging microscopy-nano (FLIM-Nano) characterization of the target perovskite film around the P1 scribe area, revealing the spatially resolved carrier recombination dynamics. Compared with Supplementary Fig. 11, the non-radiative recombination of carriers in the P1 scribe area has been greatly improved. This longer carrier lifetime confirms that defect induced non-radiative loss is prominently suppressed in the target perovskite film, consistent with other characterization results.

Having established the enhanced crystallinity and reduced degradation near the P1 scribe line in the target film, we further examined its performance in the P2 scribe area. Micro-FTIR mapping shows a more confined loss of organic cations, indicating a mitigated thermal impact (Supplementary Figs. 48, 49). Two-dimensional TOF-SIMS mapping provides further chemical insight (Fig. 4e). Compared to the control film (Fig. 3b), the FA+ signal in the target exhibits a broader and brighter band adjacent to the P2 scribe, indicating better retention of organic cations under laser-thermal exposure. Concurrently, the stronger PbI+ intensity suggests reduced conversion of lead iodide species into lead oxides. We attribute these improvements to the enhanced crystallinity of the target film, which endows it with greater resistance to thermally-driven decomposition and oxidation. The photovoltaic performance evaluation conducted through PL mapping further confirms this improvement, indicating that the range of high defect density and poor charge extraction in the target perovskite/Spiro-OMeTAD films is significantly narrower (Supplementary Fig. 50a). Moreover, the target perovskite film itself demonstrates a higher overall PL intensity (Supplementary Fig. 50b), reflecting superior crystallinity and lower non-radiative recombination losses. Collectively, these results demonstrate that the target film confines the scribe-induced thermal damage to a smaller area, contributing directly to enhanced module performance and operational stability.

Finally, building upon the improvements at the P2 scribe line, the performance of the target film is further evaluated in the P3 area where the laser energy was higher. To assess the chemical impact, two-dimensional TOF-SIMS mapping is employed to analyze the elemental distribution (Fig. 4f). Compared with the control (Fig. 3e), the FA+ signal in the target film exhibits a brighter and more uniform band adjacent to the scribe line, indicating a reduced loss of organic cations and thus a lower degree of thermal damage. This result demonstrates the enhanced tolerance of the high-quality target perovskite film under high-energy laser irradiation. Furthermore, the formation of Ag2I+ is confined to a narrower region around the scribe, which again corroborates the mitigated thermal decomposition of both the perovskite and the silver electrode in the target module. PL mapping of the target film around the P3 scribe line reveals a spatially narrower zone of elevated emission, coupled with an overall weaker PL intensity (Supplementary Fig. 50c). This indicates the higher tolerance of the high-quality perovskite film against laser-induced thermal damage.

Photovoltaic Performance and Stability Study of PSCs and PSMs
Given these significant improvements in quality of perovskite films around the P1 scribe area, we fabricate complete PSCs and PSMs to investigate their photovoltaic performance and stability, respectively. Hereafter, the FAPbI3 precursor solution is referred to as ‘control’, further addition of 2 mol% of BDECl as ‘target’. Figure 5a displays the current density-voltage (J-V) curves (reverse) of the champion control and target PSCs, in which the aperture area is 0.102 cm2. After adding 2 mol% BDECl to perovskite precursor solution, the highest PCE of 26.05% is achieved at forward scan (FS) and the reverse scan (RS) PCE is 25.94% (Supplementary Table 3). As a comparison, the control device obtains a relatively lower FS PCE of 24.54% and RS PCE of 23.97% (Supplementary Table 4). The corresponding external quantum efficiency (EQE) spectra of the control and target PSCs are shown in Supplementary Fig. 51, in which the value of integrated short-circuit current density (JSC) is basically consistent with that obtained from the J-V curves. Considering the excellent performance of small-area (0.102 cm2) devices, PSCs target devices show improved photovoltaic performance compared with control. The J-V curves of the best devices that the PCE value of 25.52% are shown in Supplementary Fig. 52a, and Supplementary Fig. 52b shows the corresponding photograph.

To investigate the impact of improved film homogeneity on large-scale applications, PSMs is fabricated from the perovskite precursor solution with BDECl added. A module consisting of seven sub-cells with an aperture area of 25 cm2 exhibit a high PCE of 24.70% with a VOC of 8.24 V, a JSC of 3.73 mA cm−2 and FF of 80.43% (Fig. 5b, Supplementary Table 5). When the aperture area is quadrupled, the module consisting of ten sub-cells with an aperture area of 100 cm2 showed a PCE of 23.89% with a VOC of 11.71 V, a JSC of 2.68 mA cm−2 and an FF of 76.19% (Fig. 5c, Supplementary Table 6). We sent the large-area module to the South China National Center of Metrology (SCM) for certification. The module achieved a PCE of 23.55% with a VOC of 11.69 V, a JSC of 2.67 mA cm−2 and an FF of 75.36% (Supplementary Fig. 53), this is the highest certified efficiency reported for modules (Supplementary Fig. 54).

Previously, we demonstrate that incorporating BDECl significantly enhances the crystallinity and photovoltaic performance of perovskite films, directly impacting defect behavior and corresponding device performance. To verify the stability of perovskite film in the P1 scribe area from a device perspective, the long-term stability of modules (with an aperture area of 25 cm2) is evaluated using EL-EQE tracking based on the ISOS-D-1 protocol. The fresh target PSMs achieve an average maximum EQE of 8.16%, compared to 5.87% for control PSMs, indicating that the defects related to non-radiation losses in the perovskite absorber are significantly suppressed by the BDECl process. After 960 h, the target PSMs retain 7.23% of their maximum EQE, while the control PSMs retain only 1.75%, demonstrating the superior stability of target PSMs (Fig. 5d). Additionally, the PCE evolution of unencapsulated PSCs and PSMs is monitored under 1-sun illumination in ambient air (~15% RH) at room temperature following the ISOS-L-1 protocol. As shown in Fig. 5e and Supplementary Fig. 55, the target PSCs and PSMs (with an aperture area of 0.102 cm2 and 25 cm²) deliver a high retention (95.37% and 91.33%) of their initial PCE after 2400 h testing, respectively, which clearly outperforms the control PSCs and PSMs. The long-term operational stability of the unencapsulated modules base on control and target is also tested with maximum power point tracking (MPPT) under 1-sun illumination at 25 °C with a N2 flow and full solar illumination, as depicted in Fig. 5f. After 360 h of continuous illumination, the control and target module retained ~43.9% and 98.6% of their initial efficiencies, respectively. After exposing the same batch of modules to different durations of light exposure, followed by Top-view SEM characterization of the bottom interface of the peeled-off perovskite films (Supplementary Fig. 56). The perovskite films in the scribe area of the control device exhibited numerous voids after light exposure (Supplementary Fig. 57), which is closely related to their rapid performance decline. In contrast, the target module still maintained a uniform perovskite film after 120 h of light exposure (Supplementary Fig. 58), indicating the performance of the target module hardly deteriorated. These results confirm that incorporating BDECl in the perovskite precursor solution enhances both defect suppression and chemical stability, resulting in markedly improved PSMs stability.

Furthermore, to verify the specific contribution of BDECl towards improving perovskite crystallization within the P1 scribe areas, we analyzed the performance of the device on the customized substrate (Supplementary Fig. 59). The electroluminescence (EL) images provided in Supplementary Fig. 60 offer further visual evidence. This superior stability is closely associated with BDECl’s suppression of overall device defects.

Since the target PSMs with additive engineering exhibit improved stability, their stability is compared with that of the target small-area devices (0.102 cm2) under different kinds of stressors. First, unencapsulated devices are tested in ~15% RH ambient conditions according to ISOS-D-1. After 3120 h of aging, the target PSCs exhibit a low, 4% (relative) PCE loss, compared with 7% (relative) efficiency loss seen in the target PSMs (Fig. 5g). Additives significantly enhanced stability in both PSCs and PSMs, particularly the PSMs narrow the stability gap with the PSCs (compared to Fig. 1b). Then, the PSCs and PSMs are tested under prolonged thermal exposure at 85 °C in nitrogen, applying the ISOS-D-2 procedure. The target PSCs retain 89% of their initial PCE after 1488 h of continuous heating, and the PSMs retain 80% of their initial performance (Supplementary Fig. 61). Under damp heat conditions (85% RH, 85 °C) according to ISOS-D-3 protocol, encapsulated PSCs and PSMs show PCE retentions of 91% and 86%, respectively, after 1000 h testing (Supplementary Fig. 62), demonstrating comparable high stability. Next, the operating stability of the unencapsulated PSCs and PSMs operating in the nitrogen-filled glovebox is investigated under 1 sun at MPPT. After 1200 h of continuous operation under 1 sun illumination (ISOS-L-1I protocol), the PCE of PSC is 24.91%, and the corresponding PCE of PSM is 23.03%, both showing reliable operational stability (Supplementary Fig. 63). Diurnal cyclic aging is further simulated to investigate the device fatigue behavior. Tracking over 24 h diurnal cycle operation (12 h light and 12 h dark) in the nitrogen-filled glovebox follows the ISOS-LC-1I protocol. As shown in Supplementary Fig. 64, after 21 aging cycles, the efficiency of the target PSC and PSM hardly decrease. Finally, the accelerated aging procedure is further set, and the light/dark cycle time (Supplementary Fig. 65, inset) is 2 hours, 4 h and 8 h, etc. Surprisingly, both the target PSCs and PSMs maintain more than 95% of their initial PCE after 120 h of light/dark cycling.

Finally, based on the previous conclusion that the addition of BDECl can effectively improve the crystallization quality of the p-i-n structure films, the p-i-n structured PSCs and PSMs are fabricated to systematically evaluate their performance and stability. The results demonstrate that BDECl similarly enhances the photovoltaic performance and light stability of the p-i-n structured PSCs and PSMs (Supplementary Figs. 66, 67).

Methods
Materials
All chemicals and reagents are directly purchased and used without further optimization or purification, including anhydrous N,N-dimethylformamide (DMF, purity 99.8%, Sigma-Aldrich with molecular sieve), N-methylpyrrolidone (NMP, purity 99.7%, Sigma-Aldrich) and acetonitrile (purity 99.8%, Sigma-Aldrich with molecular sieve), Isopropyl alcohol (IPA, anhydrous, 99.5%, Sigma-Aldrich), Ethanol (EtOH, 99.5%, SuperDry, J&K Scientific), chlorobenzene (CB, purity 99.8%, Sigma-Aldrich), methylammonium iodide (FAI, Xi’an Yuri Solar Co., Ltd.), methylammonium chloride (MACl, Xi’an Yuri Solar Co., Ltd.), Methanebromide (MABr, Xi’an Yuri Solar Co., Ltd.), cesium iodide (CsI, Xi’an Yuri Solar Co., Ltd.), lead(II) iodide (PbI2, purity 99.999%, Alfa Asear), Lead(II) bromide (PbBr2, Xi’an Yuri Solar Co., Ltd.), (E)-But-2-ene-1,4-diaminedihydrochloride (BDECl, purity 97%, Macklin), tin(Ⅳ) oxide (SnO2, 15% in H2O colloidal dispersion liquid, Alfa Asear), phenylethylammonium iodide (PEAI, Xi’an Yuri Solar Co., Ltd.), lithium bis(trifluoromethylsulfonyl) imide (Li-TFSI, purity 98%, Alfa Asear), 2,2’,7,7’-Tetrakis [N,N-di(4-methoxyphenyl) amino]-9,9’-spirobifluorene (Spiro-OMeTAD, purity 99%, Luminosity Technology crop), 4-tert-butylpyridine (tBP, Sigma-Aldrich), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (Xi’an Yuri Solar Co., Ltd.), [2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic Acid (MeO-2PACz, purity 98%, TCI), Al2O3 dispersions (100 nm, 20 w.t.% in isopropanol, Innochem), [6,6]-phenyl-C61-butyric acid methylester (PC61BM, Xi’an Yuri Solar Co., Ltd.), Bathocuproine (BCP, purity 95%, TCI), Silver (Ag) was purchased from commercial sources with high purity (≥99.999%).

Synthesis of spiro-OMeTAD2·+(TFSI−) 49
To an oven-dried 50 mL flask are added spiro-OMeTAD (1.26 g, 1 mmol) and 20 mL anhydrous dichloromethane (DCM) with stirring under nitrogen atmosphere. Silver(I) bis(trifluoromethanesulfonyl)imide (Ag-TFSI) (0.78 g, 2 mmol) is added over 5 min at room temperature. The flask is evacuated and backfilled with nitrogen. The resultant mixture is stirred at room temperature for 24 h. The reaction is diluted by adding dichloromethane. A gray precipitate of silver(0) is filtered off by Anopore inorganic membrane, and the solvent from the filtrate is removed to leave a dark solid. The solid is dissolved in a minimal amount of dichloromethane and precipitated in dry diethylether. The resulting fine and dark powder spiro-OMeTAD2·+(TFSI−) is collected via filtration through Anopore inorganic membrane. The dark crystal is obtained by vapor diffusion of diethylether into concentrated DCM solution of spiro-OMeTAD2·+(TFSI−) at 8 °C.

Synthesis of 4-tert-butyl-1-methylpyridinium-based salts49
To a 100 mL flask are added tBP (1.35 g, 10 mmol) and anhydrous acetonitrile (10 mL) with stirring under nitrogen atmosphere. Iodomethane (4.2 g, 30 mmol) in anhydrous acetonitrile (2.5 mL) is added by a dropping funnel over 30 min at room temperature. The resultant mixture is heated under reflux for 16 h then left at room temperature. After removal of solvent under reduced pressure, the crude product 4-tert-butyl-1-methylpyridinium iodide (TBMP+I−) is obtained, which is then purified by recrystallization. Anion exchanges are used to achieve other TBMP-based salts. To a solution of TBMP+I− (1.39 g, 5 mmol) in 5 mL methanol, a solution of silver(I) bis(trifluoromethanesulfonyl)imide (Ag-TFSI) (10 mmol) in acetonitrile (5 mL) is added dropwise to the heated reaction mixture under magnetic stirring. A thick yellow precipitate of silver(I) iodide formed. After 4 h reflux, the precipitate is filtered off and rinsed with methanol, and the solvent from the filtrate is evaporated to leave a waxy solid 4-tert-butyl-1-methylpyridinium bis(trifluoromethanesulfonyl)imide (TBMP+TFSI−).

Preparation of small-area perovskite solar cells
n-i-p structured: ITO glass is cleaned by sequentially washing with detergent, deionized water (DI), acetone and isopropanol (IPA). Before use, the ITO glass substrate is cleaned with Plasma for 10 min. Then the substrate is spin-coated with a thin layer of SnO2 nanoparticle film at 3000 r.p.m. for 30 s, and then annealed at 150 °C for 30 min. The SnO2 colloid is prepared by diluting the as purchased tin(IV) oxide colloid precursor with distilled water (1:3 volume ratio). For control devices, the FAPbI3 perovskite precursor is prepared by dissolving 1.55 mmol PbI2, 1.5 mmol FAI and 0.3 mmol MACl in 1 mL mixed solution of DMF:NMP (8.5:1.5 volume ratio). For the target devices, another 0.03 mmol BDECl was added in the perovskite solution. The perovskite films are obtained by spin-coating the perovskite precursor onto an ITO/SnO2 substrate at 8000 rpm for 45 s. The films are annealed at 150 °C for 10 min, and PEAI with concentration of 2 mg/ml in IPA solution is dynamically spin-coated on top (4000 rpm, 30 s) and annealed at 100 °C for 5 min. The IM radical doping of spiro-OMeTAD is initiated by mixing 90 mg ml−1 Spiro-OMeTAD in the chlorobenzene solution with 14 mol % spiro-OMeTAD2·+(TFSI−) and 20 mol % TBMP+TFSI−. The solution is dropped onto the surface of film and spin-coated at 3000 rpm for 30 s. After drying, the common electrode is scraped off, and then the Ag contact electrode with a thickness of 100 nm is evaporated under a high vacuum level of 3.5 × 10−4 Pa.

p-i-n structured: The inverted perovskite solar cells (PSCs) are studied in this paper with an architecture of ITO/MeO-2PACz/Al2O3/perovskite/PEAI/C60/BCP/Ag. MeO-2PACz (0.5 mg ml−1 in ethanol) as HTL is deposited on ITO at 3000 rpm for 30 s and annealed at 100 °C for 10 min. Then the substrate is spin-coated with a thin layer of Al2O3 film at 5000 rpm for 30 s, and then annealed at 100 °C for 10 min. The Al2O3 colloid (1.4 mg ml−1) is prepared by diluting the as purchased Al2O3 dispersions with IPA. Subsequently, the active layer is prepared. The perovskite films are obtained by spin-coating the perovskite precursor onto an ITO/MeO-2PACz/Al2O3 substrate at 8000 rpm for 45 s, and then are annealed at 100 °C for 10 min. Then, PEAI (2 mg ml−1 in IPA) is spin-coated at 3000 rpm for 30 s, and then annealed at 70 °C for 5 min. After that, PCBM (20 mg ml−1 in CB) as ETL is spin-coated at 3000 rpm for 30 s. BCP (0.5 mg ml−1 in IPA) is dynamically deposited on PCBM at 4000 rpm for 30 s. Finally, 100 nm Ag is thermally evaporated under high vacuum (3.5 × 10-4 Pa).

Preparation of large-area perovskite submodules
The designated P1 pattern of Glass/ITO is cleaned and deposited with an SnO2 layer or SAMs (MeO-2PACz/Al2O3) layer as described above. The perovskite precursor solution is printed onto the 50 mm × 50 mm and the 100 mm × 100 mm substrates in ambient atmosphere (temperature, 20 ± 2 °C; relative humidity, 15 ± 5%). The perovskite film is fabricated by slot-die coating under ambient conditions. The distance between the slot-die head and the substrate is set at 100 μm, with a relative moving speed of 5 mm s−1 between the die head and the substrate. The liquid supply rate of the injection pump is controlled at 8 μL s−1. The perovskite precursor film is dried with the assistance of an N2 knife. The N2 knife is positioned ~100 mm away from the slot die head and is angled at roughly 70° with respect to the substrate, directing N2 flow away from the slot-die head. The N2 knife stands about 10 mm above the substrate, operating at an N2 pressure of around 0.3 MPa with a gas flow velocity of ~35 mm s−1. The ambient temperature is maintained at about 23 °C with a relative humidity below 15% during this process. Subsequently, these semi-dried precursor films are transferred to a 150 °C hot plate and annealed for 10 minutes to form the perovskite film. A 2 mg mL−1 PEAI/IPA solution is blade coated onto the perovskite film, followed by thermal annealing at 100 °C for 5 min. Then, the Spiro-OMeTAD or C60/BCP are deposited as described above. Finally, a picosecond laser (365 nm) is used to etch the previously deposited films to form a P2 pattern and etched again to form a P3 pattern after evaporation of the Ag electrode.

Film characterizations
Large-area perovskite films is conducted by desktop multi-functional and high-precision coating equipment that integrates thickness detection and spectral analysis (SSL-BCM-003, Nantong Rollshine Photoelectric Technology Co., Ltd.). The morphology of films is measured by AFM (nanoscope multimode Bruker) and SEM (JEOL, JSM-7500F, 104 Japan) at an accelerating voltage of 5.0 KV. Transmission Electron Microscopy (TEM) is recorded by using a Thermo Fisher Talos F200S G2. X-ray diffraction (XRD) is measured by using a D8-Discover 25 diffractometer (Bruker). The steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements at the peak emission of ~808 nm (on the excitation at 535 nm) were carried out by a steady state and lifetime spectrometer (FLS920, Edinburgh Instruments Ltd.). And the TRPL excitation fluence is ≈4 nJ cm−2 from a 405 pulsed laser with a wavelength of 405 ± 8 nm and pulse width of 45 ps, at a repetition rate of 0.1 MHz. The PL decay data was recorded using time-correlated single photon counting technique. Fluorescence lifetime imaging microscopy (FLIM, Fast Flim Q2, ISS lnc.) was scanned by PL Mapping in a 30 × 30 μm2 area with an excitation wavelength of 532 nm. The ultraviolet-visible (UV-vis) spectra are measured by Agilent Tech. Inc. Cary 5000 spectrophotometer. Grazing-incidence wide-angle X-ray scattering (GIWAXS) data were obtained at beamline BL16B1 of Shanghai Synchrotron Radiation Facility (SSRF). The monochromatic of the light source was 1.24 Å. The acquisition time for the film is 5 s. The data were recorded by using the two-dimensional image plate detector of Pilatus 1M from Dectris, Switzerland. In-situ GIWAXS data were obtained at beamline BL16B1 of SSRF. The acquisition time for a single piece of data is 2 s, incident angle is 0.3°, which maximized the scattering intensity from the samples. The perovskite thin films are characterized using a Thermo Fisher Scientific/Nicolet iN10 Fourier Transform Infrared (FTIR) Microscope equipped with a cooled detector in reflection mode. The measurements are performed with a collection time of 12 s, 64 scans, and a step size of 50 μm × 50 μm, covering a spectral range of 4000 to 675 cm−1.

Device characterizations
The current density-voltage (J-V) characteristics were generated by the solar simulator (Enlitech, SS-F5-3A, 100 mW cm−2 irradiance and AM 1.5G sunlight) in conjunction with the Keithley 2400 SourceMeter. The forward scan range was from −0.2 V to 1.2 V, and the reverse scan range was from 1.2 V to −0.2 V, each step being 0.02 V. The scan rate was 200 mV s−1. The EQE spectra are recorded on a commercial EQE measurement system (Enlitech, QE-R3011) in nitrogen environment. The illuminated currents were measured under the solar simulated (Enli-Tech, 100 mW cm−2 and AM 1.5G irradiation). The incident photo-to-electron conversion efficiency spectra (IPCE) measurements were detected under monochromatic illumination (Oriel Cornerstone 260 1/4 m monochromator equipped with Oriel 70613NS QTH lamp) in a glovebox (N2 atmosphere). The maximum power point (MPP) was conducted by a glovebox (N2 atmosphere) with the solar simulator (Enlitech, 100 mW cm-2 irradiance and AM 1.5G sunlight) of continuous irradiation.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This manuscript investigates the degradation mechanisms in the laser scribe area of large-area perovskite solar modules (PSMs) and proposes an additive engineering strategy to mitigate these issues. The authors identify confinement crystallization and substrate difference induced by laser scribing as key factors causing defects (voids, PbI₂ accumulation) and accelerated degradation in the scribe area. By introducing BDECl to form a 2D perovskite template, the work achieves bottom-up quasi-epitaxial growth of α-FAPbI₃, significantly improving film quality and module stability. Overall, this work provides a new perspective and approach for the study of module stability in the perovskite photovoltaic field, which is of great significance. Therefore, I recommend the publication of this manuscript in Nature Communications after a minor revision.\n1. In the manuscript, the authors found voids in the buried interface in both Fig. 1e and 2e. To more intuitively demonstrate the reasons for the aging of the buried interface, the authors should study the buried interface of fresh devices.\n2. In the main text, the aging test of the film was conducted in a low-humidity and low-oxygen atmosphere, but in the caption of Fig. 2a, it is “ambient air with 15% relative humidity (RH) at room temperature”. Please have the authors carefully check and verify.\n3. In Fig. 3c, although the authors framed the position of lead iodide, the signal of lead iodide could not be significantly distinguished. The authors should make appropriate adjustments or provide supplementary explanations.\n4. The authors claim that the poor quality of perovskite is due to top-down crystallization near the scribe area (Fig. 3e), but there is a lack of actual evidence to prove that perovskite crystallizes top-down in this area. Please provide evidence of the variation of the crystallization quality of perovskite with depth. Additionally, the authors should confirm that the BDECl-modified perovskite crystallizes via a bottom-up mechanism.\n5. In the main text of Crystal Growth Regulation by Additive Engineering, the authors stated that “a large number of BDE+ cations to volatilize from the film”. Meanwhile, the 2D GIWAXS results also confirmed this statement. But BDE+ cations still exist in the 3D perovskite shown in the schematic diagram of Fig. 4b. Please carefully check the consistency between the description in the main text and the schematic diagram.\n6. For Fig. 4e and 4f, the UV−vis absorbance spectra, steady-state PL spectra and transient state PL decay spectra are performed on what substrates and in which regions? The authors should provide supplementary explanations in the caption. Furthermore, in the schematic diagrams of Fig. 3e and 4b, the elements of each part are not indicated. The authors should explain them in the figures.\n7. Regarding the device performance section, the data related to the performance of the p-i-n structure module is limited. The improved performance data should be provided to verify the universality of the BDECl material.", "reviewer_2": "The manuscript addresses a relevant challenge in the upscaling of perovskite solar cells (PSCs), namely the degradation mechanisms associated with the P1 scribe in monolithic perovskite solar modules (PSMs). While several previous studies have focused on stability issues linked to the P2 and P3 scribes, such as direct contact of perovskite with electrodes and exposure to ambient conditions. The authors aim to highlight the often-overlooked role of the P1 scribe. They propose that the difference in substrate composition at the P1 depression (Glass/CTL vs ITO/CTL) alters perovskite crystallization kinetics, which in turn could affect device stability. An additive engineering strategy is introduced to mitigate this. Although the literature does discuss coating and stability issues related to the P1 scribe individually, the perovskite crystallization behavior at this trench and its stability together is not well studied.\nIt is well established, particularly in lab-scale, small-area devices, that perovskite crystallizes differently on Glass/CTL and ITO/CTL, as also demonstrated by the contrast between scribed and non-scribed areas in this study. Additive strategies, including 2D materials, are commonly used in large-area devices to enhance uniform crystallization and passivate defects across the active area, including the P1 region. This makes the manuscript’s novelty relatively limited in terms of the perovskite crystallization perspective.\nThe topic is of potential interest to the perovskite community, particularly if the link between crystallinity in the P1 scribe region and overall module stability can be clearly established. However, the current version of the manuscript lacks conclusive evidence to support this central claim. In particular, the presented stability data does not sufficiently isolate the impact of the P1 scribe from other contributing factors. Several of the characterizations are performed on films rather than full devices, and stability comparisons are primarily made between small-area and large-area devices rather than between control and target PSMs with and without additive strategies.\nGiven the limited novelty and the lack of definitive evidence that the observed stability improvements are specifically due to mitigation at the P1 scribe, I am not able to recommend the manuscript for publication. I encourage the authors to consider the following specific suggestions to strengthen the manuscript:\nMajor Comments:\n1. The statement that “primary loss arises from a reduction in the fill factor (FF) due to decreased perovskite crystal uniformity” should be rephrased to reflect that other factor such as increased series resistance, shunt paths, and contact resistance, can also contribute significantly to FF losses during scaling.\n2. Most of the stability data compares small-area to large-area devices, while the manuscript’s main focus is on mitigating P1-related degradation in PSMs. A more appropriate comparison would be between control and target large-area devices. Although EQE-EL measurements are presented under dark, controlled conditions, they may not capture the full degradation pathway. The rationale behind choosing this method over continuous maximum power point (MPP) tracking under light exposure should be clearly discussed.\n3. In Supplementary Figure 16b, the authors show ISOS-L1 stability tests, but it remains unclear how they decouple the specific contribution of P1 from broader effects of additive engineering, which can affect crystallization and passivation across the bulk and interfaces (including P2 and P3 regions). The manuscript would benefit from a more detailed explanation or supporting experiments to isolate the role of P1 from other mechanisms.\n4. To convincingly attribute improvements to P1 perovskite degradation mitigation, additional characterization is necessary. PL imaging, SAM, XRD, or cross-sectional TEM analyses localized around the P1, P2, and P3 regions after stability testing (control vs target) would greatly enhance the claim. Without this, it's difficult to isolate P1 as the dominant degradation pathway for PSMs.\n5. Figures 1–4 primarily examine perovskite films deposited on substrates, whereas in real devices the P1 region is a buried interface. Environmental exposure is therefore not equivalent. Characterizing P1 degradation in complete module stacks would be more relevant.\n6. In SI Figure 7C, even non-scribed areas on the ETL show significant δ-phase formation, suggesting that crystallization and degradation are not limited to P1 scribe regions, where target samples may be benefited due the passivation at buried interface due to addtive. This raises questions about the specificity of the additive’s impact on P1 and indicates that other degradation pathways (selection of configuration n-i-p or p-i-n, CTLs etc.) may be equally or more important.\n7. The influence of substrate variation (Glass/CTL vs ITO/CTL) may also apply to small-area devices due to edge effects. It would be useful to discuss this and how it might influence perovskite crystallization and degradation at the ITO/glass boundary, even in 0.1 cm² devices.\n8. Figure 1f would benefit from higher magnification to clearly show void formation. Additionally, the SEM images suggest the perovskite layer appears planar, whereas profilometry indicates a trench in the P1 area. Clarification is needed, especially given the depth mismatch between the depression (from profilometer) and film thickness (from SEM).\n9. Contact angle measurements on bare glass (SI Figure 6) may not reflect device-relevant surfaces, which include CTLs. Without surface treatment like UV-ozone, glass generally shows higher contact angles, so linking this to crystallization in P1 needs more contextual justification.\n10. Details on laser scribing parameters (GFF, scribe width, laser type) and the proportion of active vs dead area would enhance reproducibility and contextual understanding of the results, especially since the work aims to address stability linked to P1 scribe geometry.\n11. Given known stability issues of ETLs in n–i–p architectures, it would be helpful to explain the choice of this structure over p–i–n. If p–i–n devices were also investigated, including their results would provide a broader perspective. The role of Al₂O₃ nanoparticles in p–i–n devices (mentioned briefly) should also be clarified.\n12. In Figure 1b, the labels should read \"device (PSC)\" vs \"module (PSM)\" instead of \"control\" vs \"target.\" Please revise for clarity.\n13. The manuscript mentions localized XRD at the P1 scribe, which is <50 µm wide. More information is needed on how such high spatial resolution was achieved and whether any beam broadening or signal overlap from adjacent regions might affect the accuracy.\nThe work addresses an underexplored aspect of PSM stability related to P1 scribe-induced crystallization inhomogeneity. The conceptual link is interesting, and the strategy of additive engineering aligns with current trends in module-scale optimization. However, the present data does not definitively isolate P1-related degradation or convincingly demonstrate that the additive strategy improves long-term stability through P1 mitigation alone. Additional characterizations and a more focused experimental design could significantly enhance the manuscript. I hope the authors find these suggestions constructive in refining their work.", "reviewer_3": "This manuscript addresses a relevant and important topic on PSM stability, focusing specifically on the effect of P1 laser scribing. The authors show that P1 laser scribing negatively impacts the stability of PSMs by introducing defects (PbI₂, voids, δ-phase perovskite) due to confinement crystallization. They address this by using BDECl additive, significantly improving film quality, module performance, and stability. The approach, combining optical characterization and morphology analysis, is valuable. However, the manuscript lacks critical experimental details, clear data presentation, and evidence supporting key claims. Several key figures have poor resolution or insufficient clarity, making interpretation difficult. While this study addresses important issues, the evidence presented is insufficient to support the conclusions, and the presentation also requires significant improvement. I recommend Major Revision. The authors should add missing experimental details, improve data presentation, and perform additional measurements or include controls to validate their claims. The following specific comments and recommended changes that need to be addressed to strengthen the manuscript.\n1. The manuscript lacks detail on the laser processing parameters used for P1 (e.g., laser wavelength, pulse duration, fluence, scan speed, film side or substrate side illumination?, etc.) Additionally, the uniformity and quality of the P1 lines (morphology surface and cross-section, OM images, presence of residual ITO or debris) are not described. This is very important because the impact of P1 on module stability can vary significantly depending on the scribing conditions.\n2. Could varying the P1 conditions improve grain formation in the scribed areas as well? It is essential to present grain growth results across a broader range of P1 conditions. Showing only two cases is insufficient and does not adequately support the conclusions drawn.\n3. The aging conditions and experimental environments of the various samples appear to be inconsistent throughout the manuscript. Can the authors explain why these conditions are not standardized? Also, descriptions such as “low humidity and low oxygen” are not sufficiently precise. Please provide precise numbers.\n4. The authors attribute the decrease in module efficiency primarily to a reduction in FF. Could you specify whether this reduction is mainly influenced by series or shunt resistance? Additionally, were Jsc and Voc unaffected by degradation? It would be helpful to present time-dependent J–V curves clearly demonstrating the evolution of these parameters. (If PbI₂ formation indeed occurs, Voc also decrease)\n5. What evidence is presented for PbI₂ formation? In Figure 2e, the claim might be that there are bright or contrast features in an SEM or some mapping indicating PbI₂, but the image resolution is low and not clearly explained.\n6. On page 7, the authors state that \"the perovskite in the P1 scribe region is almost completely decomposed, and the decomposed region begins to diffuse into the non-scribed region.\" The current manuscript lacks clear visual data showing this decomposition diffusion, so clear and convincing image-based evidence should be presented.\n7. In Figure 2, the OM images exhibit color changes; can you clarify what these color differences indicate? Additionally, why were different measurement conditions used for OM and PL data?\n8. Do the authors have stability results regarding the impact of P2 and P3 scribing processes? It would be beneficial to refer to the recent study by Jeong et al. (Solar RRL, 2024", "reviewer_doi": "10.1002/solr.202301040) for comparison and further insights.\n9. On page 9, the authors state, “A significant accumulation of PbI₂ is observed at the grain boundaries.” Could you clarify what specific experimental data support this claim?\n10. Figures 1d, 2e, and 4d are cited as important evidence, but their image quality is poor – can the authors provide clearer, high-resolution visuals?\n11. In Figure S1, the authors state, \"This degradation rate is significantly faster than that of small-area PSCs.\" Could you clarify why the decomposition rate is faster in modules with smaller sizes compared to larger-area modules?\n12. Regarding the XPS data statement: “The characteristic peaks of Pb 4f and I 3d of perovskite films in the scribe area exhibit higher peak intensities and narrower widths, indicating a greater PbI₂ content in this area”—can the authors clarify how this directly confirms PbI₂ formation rather than simply reflecting variations in perovskite film thickness? If PbI₂ content indeed changed significantly, wouldn't a corresponding alteration in iodine signals be expected?\n13. Supplementary Figure 2b suggests that the depression in the P1 scribe area could not be fully covered by the electron transport layer (ETL). However, direct observational evidence confirming incomplete ETL coverage is missing. Considering that ETL coating coverage could vary substantially with different laser-processing parameters, it is important to provide clear SEM images verifying ETL continuity in this area.\n14. The authors indicate that grain growth in the P1 region improves after BDECl treatment; however, the grain structure in the P1 area is not clearly visible in Figure 4d. Could you provide higher-resolution SEM images? Additionally, Figure 4d suggests that grains near the scribed area appear larger compared to other regions. Can the authors explain the reason?\n15. What are the fundamental differences in their processing mechanisms and morphologies in p1 scribing? (Nanoseconds vs. femtoseconds?)\n< Other Technical Comments >\n• Add page numbers and consistent subscripts (e.g., FAPbI₃, BDEPbI₄).\n• Please clarify the specific emission wavelength range of TRPL measurement?"}, "author_response": "Institute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nResponse to reviewers’ comments\nFor Reviewer #1:\nRemarks to the Author\nThis manuscript investigates the degradation mechanisms in the laser scribe area of large-area\nperovskite solar modules (PSMs) and proposes an additive engineering strategy to mitigate these issues.\nThe authors identify confinement crystallization and substrate difference induced by laser scribing as\nkey factors causing defects (voids, PbI₂ accumulation) and accelerated degradation in the scribe area.\nBy introducing BDECl to form a 2D perovskite template, the work achieves bottom-up quasi-epitaxial\ngrowth of α-FAPbI₃, significantly improving film quality and module stability. Overall, this work\nprovides a new perspective and approach for the study of module stability in the perovskite\nphotovoltaic field, which is of great significance. Therefore, I recommend the publication of this\nmanuscript in Nature Communications after a minor revision.\nReply: Thanks for the high appreciation you have given us.\n1. Comments: In the manuscript, the authors found voids in the buried interface in both Fig. 1e and\n2e. To more intuitively demonstrate the reasons for the aging of the buried interface, the authors should\nstudy the buried interface of fresh devices.\nReply: Thank you very much for your constructive suggestions, which are essential for improving the\nquality of the manuscript and showing the perovskite defects in the scribe area. We supplemented the\nSEM characterization on the bottom surface of the control and target films. As shown in\nSupplementary Fig. 6 and Supplementary Fig. 27, there are numerous holes and the accumulation\nof PbI at the bottom interface of the control film in the scribe area. It can be observed that the\n2\nmorphology of the bottom interface of the target film in the scribe area has been significantly improved.\nⅰ\nⅰ\n1 μm\nⅱ\nⅱ\n20 μm 1 μm\nSupplementary Fig. 6 | Scanning electron microscope (SEM) images of the bottom surface of fresh\nperovskite films in the non-scribe area (ⅰ) and the scribe area (ⅱ).\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 27 | SEM images of the bottom surface of the target film in the non-scribe area\n(ⅰ) and the scribe area (ⅱ).\n2. Comments: In the main text, the aging test of the film was conducted in a low-humidity and low-\noxygen atmosphere, but in the caption of Fig. 2a, it is “ambient air with 15% relative humidity (RH)\nat room temperature”. Please have the authors carefully check and verify.\nReply: Many thanks for the reviewer’s comments. Fig 2a was tested in an ambient atmosphere with\nlow-humidity. After our review, we revised the description in the main text, changing \"in a low-\nhumidity and low-oxygen atmosphere\" to \"in a low-humidity ambient air with ~15% RH\".\n3. Comments: In Fig. 3c, although the authors framed the position of lead iodide, the signal of lead\niodide could not be significantly distinguished. The authors should make appropriate adjustments or\nprovide supplementary explanations.\nReply: Thank you very much for your wise suggestions. As shown in Fig. 3c, the in-situ GIWAXS\nmeasurement is conducted along the in-plane direction, while PbI is mainly in the out-of-plane\n2\ndirection. Therefore, this is not clearly visible in the Fig. 3c. We have added an illustration to show\nthe PbI scattering peak signal along the out-of-plane direction. This clearly indicates the scattering\n2\npeak of PbI at 0.895 Å-1.\n2\nc, In-situ GIWAXS during thermal annealing at 150 °C using the as-deposited films in the non-scribe\narea and the scribe area. The inset in the upper right corner shows the PbI₂ diffraction peak along the\nout-of-plane direction (q ).\nz\nSupplementary Fig. 13a reveals that the as-deposited film contains a noticeable δ-phase signal (q\n= 0.83 Å-1) along with signals from an intermediate phase (FAI-PbI₂-NMP). As annealing proceeds\n(Supplementary Fig. 13b-f), the diffraction signals corresponding to the δ-phase and the intermediate\n2 0\nⅰ\nμ m\nⅱ\nⅰ\n1\nⅱ\n1\nμ\nμ\nm\nm\n(c) 3.0 3.0 2.960E+05\n2.600E+05 2.5 2.5\n2).u .240E+05\n1-Å )\n( q yx\n2\n1\n.\n.\n0\n5\n1- )\nÅ ( q yx\n2\n1\n.\n.\n0\n5\n1\n1 1\n.a (y\ntis n e\n.\n. .\n8\n5 1\n8\n2 6\n0\n0 0\nE\nE E\n+\n+ +\n0\n0 0\n5\n5 5\n1.0 1.0 δ-FAPbI3 8 tn I.000E+04\n0.5 Non-scribe area 0.5 Scribe area 4.400E+04\n8000\n100 200 300 400 500 600 100 200 300 400 500 600\nTime(s) Time(s)\n)1-Å(zq 0.90 0.89\n0.88 450 500 550 600\nPbI2\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nphase gradually diminish, while the α-phase intensity increases, indicating progressive conversion and\ncrystallization. Upon reaching 480 s of annealing (Supplementary Fig. 13h), a new diffraction signal\nemerges at q = 0.895 Å-1, attributed to the formation of PbI₂. As the annealing time is extended from\nz\n530 s to 600 s, the intensity of this signal stabilized (Supplementary Fig. 13i).\nSupplementary Fig. 13 | a-i, In-situ 2D GIWAXS of the control film in the scribe area during\nannealing with different times: (a) 0 s, (b) 5 s, (c) 10 s, (d) 30 s, (e) 60 s, (f) 120 s, (g) 300 s, (h) 480\ns, and (i) 600 s. j, 2D GIWAXS detector pixel image of the control film in the scribe area after 600 s\nof annealing. k, l, Radial intensities of 1D GIWAXS reciprocal map of the control film in the scribe\narea after 600 s of annealing.\nSupplementary Fig. 13 presents a series of in-situ 2D GIWAXS patterns capturing the structural\nevolution of the control perovskite film during thermal annealing. This dataset provides a\ncomplementary 2D visualization to the one-dimensional q -time-intensity plot shown in Fig. 3c,\nxy\nhighlighting the dynamic crystallization process. The GIWAXS detector is composed of a tiled array\nof 100k detector units (Supplementary Fig. 13j). Gaps exist between these units, resulting in missing\ndata in certain regions (q = 1.3 Å-1, q = 1.0, and 1.9 Å-1) (Supplementary Fig. 13k, l). Hence, the\nxy z\nBragg peak corresponding to α-FAPbI₃, located at q = 0.99 Å⁻¹, was monitored along the q direction.\nxy\n(\n(\n(\n(\na\nd\ng\nj )\n)\n)\n)\nW\nA\nA\nith o u t A n n e a lin g\nn n e a lin g fo r 3 0 s\nn n e a lin g fo r 3 0 0 s\n( b\n( e\n( h\n( k\n).u.a(\nytisnetnI\n)\n)\n)\n)\nA\nA\n.5\nn n e a lin g fo r 5 s\nn n e a lin g fo r 6 0 s\nn n e a lin g fo r 4 8 0 s\n1 .0 1 .5-1\nq (Å )\nxy\n2 .0 2\n( c\n( f\n( i\n( l\n).u.a(\nytisnetnI\n.5\n)\n)\n)\n)\nA n n e a lin g fo r 1 0 s\nA n n e a lin g fo r 1 2 0 s\nA n n e a lin g fo r 6 0 0 s\n0 .5 1 .0 1 .5-1\nq (Å )\nz\nP\n2\nb I2\n.0 2 .5\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nHowever, as the PbI₂ signal predominantly appears along the out-of-plane direction, its emergence\nafter 450 s of annealing could not be adequately captured in the q direction (Supplementary Fig.\nxy\n14b). Therefore, an inset in the upper right corner of Fig. 3c displays the q -time-intensity plot focusing\nz\non the PbI₂ peak at q = 0.895 Å-1.\nz\nSupplementary Fig. 14 | Radial intensities of reciprocal space maps of different annealing times\nobtained from GIWAXS on the control film in the non-scribe area (a) and the scribe area (b).\n4. Comments: The authors claim that the poor quality of perovskite is due to top-down crystallization\nnear the scribe area (Fig. 3e), but there is a lack of actual evidence to prove that perovskite crystallizes\ntop-down in this area. Please provide evidence of the variation of the crystallization quality of\nperovskite with depth. Additionally, the authors should confirm that the BDECl-modified perovskite\ncrystallizes via a bottom-up mechanism.\nReply: Thank you very much for your constructive advice, which are very effective in improving the\nquality of the manuscript and can deepen readers' understanding of the BDECl-modified perovskite\ncrystallizes mechanism. Firstly, we used GIXRD measurement to monitor the crystallization process\nof the control film, as shown in Supplementary Fig. 11.\n).u.a(\nytisnetnI\n0 .5 1 .0\nq\n1\n(Å\nz\n.5-1\n)\n2 .0 2 .5 0.5 1.0 1.5 2.0 2.5\n).u.a(\nytisnetnI\nq (Å-1)\nxy\n).u.a(\nytisnetnI\n0 .5 1 .0\nq\n1\n(Å\nz\n.5-1\n)\n2 .0 2 .5\n600\n(a)\nT\nmi\ne\ns(\n)\n0\n600\n(b)\nT\nmi\ne\ns(\n)\nPbI2\n0.5 1.0 1.5 2.0 2.5 0\n).u.a(\nytisnetnI\nq (Å-1)\nxy\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 11 | Grazing incidence x-ray diffraction (GIXRD) measurement on control\nFAPbI films. a-f, GIXRD patterns (vertically offset for clarity, * denotes the peaks from the FAI-\n2 3\ns, (d) 30 s, (e) 60 s, and (f) 600 s.\nAs shown in Supplementary Fig. 11a, the GIXRD pattern of this film exhibits four dominant\ncharacteristic peaks at 2θ of 8.5°, 9°, 10.9°, and 12.4°, which can be assigned to the crystalline\nintermediate phase of FAI-PbI -NMP as previously reported5-7. After annealing for 1 s on a hot plate\n2\nat 150 °C, the characteristic peaks of the intermediate phase decreases, while the characteristic peaks\nof the δ phase increases. At this time, the characteristic peaks of the intermediate phase only appear at\nthe bottom of the perovskite film (the incidence angle = 3°), indicating that the part of the film converts\ninto the perovskite phase, accompanied by the evaporation of the coordinating NMP from the top\nsurface of the film. As the annealing time increases, the peaks from the intermediate phase disappears\nat large incident angle (> 1°). After annealing for 10 minutes, no peak from the intermediate phase is\nobserved at any incident angles (Supplementary Figure 11f), indicating that the intermediate phase\nhas completely converted into perovskite phase. These results suggest that the conversion of\nintermediate phase to perovskite starts at the top surface of wet film and then goes downward, instead\nof initializing at the film-substrate interface.\nSubsequently, BDECl is added to the perovskite precursor solution. We characterize the\ncrystallization process of the perovskite base on the target film, as shown in Supplementary Fig. 24.\nBefore thermal annealing (Supplementary Fig. 24a), the GIXRD pattern of this wet film exhibits 2D\nperovskite characteristic peaks at 2θ of 6.8° and 10.2° at large incident angles. At this time, a small\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\namount of the intermediate phase is present at the bottom of the perovskite (the incidence angle < 1°).\nThis indicates that the 2D perovskite at the bottom serves as a template for the quasi-epitaxial growth\nof perovskite, guiding the perovskite growth from bottom to top. After annealing for 10 minutes\n(Supplementary Fig. 24f), compared to the control film, the target film shows significantly stronger\ncharacteristic peaks at the (001) plane of 13.9°. It is indicated that the perovskite crystals preferentially\nalign along the (001) plane, resulting in higher crystallinity and fewer defects.\nSupplementary Fig. 24 | GIXRD measurement on target FAPbI films. a-f, GIXRD patterns\n3\n(vertically offset for clarity, * denotes the peaks from the FAI-PbI -NMP intermediate phase, # denotes\n2\nthe peaks from the 2D perovskite intermediate phase at the bottom of the FAPbI films annealed for\n3\ndifferent times: (a) 0 s, (b) 1 s, (c) 3 s, (d) 30 s, (e) 60 s, and (f) 600 s.\n5. Comments: In the main text of Crystal Growth Regulation by Additive Engineering, the authors\nstated that “a large number of BDE+ cations to volatilize from the film”. Meanwhile, the 2D GIWAXS\nresults also confirmed this statement. But BDE+ cations still exist in the 3D perovskite shown in the\nschematic diagram of Fig. 4b. Please carefully check the consistency between the description in the\nmain text and the schematic diagram.\nReply: We sincerely thank the reviewer for this insightful observation. We acknowledge that the\noriginal schematic in Fig. 4b inaccurately implied residual BDE⁺ in the 3D perovskite grain boundaries\nafter annealing, which contradicted the conclusion drawn from GIWAXS data (Fig. 4c). To address\nthis, we have taken the following corrective actions:\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nThe schematic diagram (Fig. 4b) has been carefully modified to remove all BDE⁺ cations from the\ngrain boundaries of the 3D perovskite phase, ensuring alignment with the main text describing the\nvolatilization and deprotonation of BDE⁺ during thermal annealing. Due to high-temperature annealing\nleads to the rapid deprotonation of BDE+ (Small Methods, 2022, 6, 2200933). Correspondingly, the\namount of BDE+ is greatly decreased and the residual δ-FAPbI is fully converted to α-FAPbI . As a\n3 3\nresult, a com positional and phase-pure α-FAPbI is obtained. The updated figure now accurately\n3\nreflects the complete removal of 2D components from the 3D perovskite.\nb, Schematic of the crystallization mechanism of the bottom-up 2D-templated FAPbI perovskite film\n3\ngrowth.\nTo further substantiate the absence of 2D phase after annealing, we performed depth-profiling\nGIXRD analysis (with incident angles ranging from 0.1° to 3°) on the film that was annealed for 10\nminutes. The results are presented in Supplementary Fig. 24. After annealing for 10 minutes, no\ndiffraction peaks corresponding to the two-dimensional perovskite phase were detected in the surface\nand the bulk regions. The unique existence of 3D perovskite diffraction peaks confirmed the complete\nconversion and volatilization of BDE⁺ throughout the entire film (Supplementary Fig. 24f).\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 24 | GIXRD measurement on target FAPbI films. a-f, GIXRD patterns\n3\n(vertically offset for clarity, * denotes the peaks from the FAI-PbI -NMP intermediate phase, # denotes\n2\nthe peaks from the 2D perovskite intermediate phase at the bottom of the FAPbI films annealed for\n3\ndifferent times: (a) 0 s, (b) 1 s, (c) 3 s, (d) 30 s, (e) 60 s, and (f) 600 s.\nThese data robustly support our claim that BDE⁺ cations are fully volatilized upon annealing, leaving\na phase-pure 3D perovskite. The revised manuscript text (Crystal Growth Regulation by Additive\nEngineering) and Fig. 4b are now fully consistent.\n6. Comments: For Fig. 4e and 4f, the UV−vis absorbance spectra, steady-state PL spectra and transient\nstate PL decay spectra are performed on what substrates and in which regions? The authors should\nprovide supplementary explanations in the caption. Furthermore, in the schematic diagrams of Fig. 3e\nand 4b, the elements of each part are not indicated. The authors should explain them in the figures.\nReply: We appreciate the reviewer’s meticulous suggestions to enhance methodological clarity and\nfigure readability. The following revisions have been implemented:\nAll optical characterizations (UV-vis absorbance, steady-state PL, transient PL decay) were\nperformed exclusively in the scribe area of the perovskite films. The captions of Fig. 4e and 4f have\nbeen revised as follows: UV−vis absorbance spectra and steady-state PL spectra (e) and transient state\nPL decay spectra (f) of perovskite films in the scribe area based on control and target. The following\ncontent is added to the main text: Compared to the control film, the defect density of the target film is\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\ncharacterized in the scribe area.\ne, f, UV−vis absorbance spectra and steady-state PL spectra (e) and transient state PL decay spectra (f)\nof perovskite films in the scribe area based on control and target.\nBoth schematics now include direct element labels to eliminate ambiguity. The annotated versions\nare now included in the revised manuscript Fig. 3e and 4b, with compositional keys integrated into the\ndiagram margins.\ne, Schematic illustration of the crystallization mechanism of the perovskite layer in the P1 scribe area.\nb, Schematic of the crystallization mechanism of the bottom-up 2D-templated FAPbI perovskite film\n3\ngrowth.\n7. Comments: Regarding the device performance section, the data related to the performance of the\np-i-n structure module is limited. The improved performance data should be provided to verify the\nuniversality of the BDECl material.\nReply: We thank the reviewer for highlighting the importance of validating BDECl’s universality\nacross device architectures. To address this, we have expanded the p-i-n structure analysis by\nfabricating both small-area devices and large-area modules, with key results now integrated into the\nrevised manuscript. The new data conclusively demonstrate BDECl’s efficacy in enhancing\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nperformance and stability across architectures.\nSupplementary Fig. 45 | a, J-V characteristics of the champion p-i-n PSCs based on control and target\nwith an aperture area of 0.102 cm2. b, J-V characteristics of the champion p-i-n PSMs based on control\nand target with aperture area of 25 cm2.\nSupplementary Fig. 46 | PCE evolution over time of unencapsulated p-i-n PSMs based on control\nand target with an aperture area of 25 cm2 under 1-sun illumination with a white light-emitting\ndiode (100 mW cm−2) in ambient air with ~15% RH at room temperature according to ISOS-L-\n1. Devices were periodically tested under AM 1.5G irradiation with a Xe arc lamp at 100 mW cm−2.\nData presented as mean ± s.d., tracing the PCE of ten devices over time for each condition.\nBased on the previous conclusion that the addition of BDECl can effectively improve the\ncrystallization quality of the p-i-n structure films, the p-i-n structured PSCs and PSMs are fabricated\nto systematically evaluate their performance and stability. The results demonstrate that BDECl\nsimilarly enhances the photovoltaic performance and light stability of the p-i-n structured PSCs and\nPSMs (Supplementary Fig. 45, 46).\n( a ) )2-mc\nAm\n( ytisned\ntnerruC\n2\n2\n1\n1\n5\n0\n5\n0\n5\n0-\nJ\nS C F F\nP C E\n.2 0\n2\n.0\nC o n tr o l\n1 .1 6 V\n5 .0 7 m A c m\n7 9 .7 9 %\n2 3 .2 4 %\n0 .2 0 .4\nV o lt a\n-2\n0g\nT a r g e t\n1 .1 8 V\n2 5 .5 4 m A c m\n8 3 .7 4 %\n2 5 .2 0 %\n.6 0 .8 1 .0\ne ( V )\n-2\n1\n(\n.2\nb ) )2-mc\nAm\n( ytisned\ntnerruC\n4\n3\n2\n1\n0\nC o n tro l\n7 .9 8\n7 .8 2\n2\n(m\n3V\nA p e\nJ SC A c m\n3 .6 1\n3 .4 6\n4\no lt a\nT a r g e\nC o n t r\nrtu re a re\n2 2 5 c m\nF F -2) (% )\n7 7 .3 6\n7 4 .5 4\n5 6\ng e ( V )\nto\nl\na :\nP C E (% )\n2 2 .3 1\n2 0 .1 8\n7 8\n92.56%\n83.49%\n2\n2\n1\n1\n1\n1\n2\n0\n8\n6\n4\n2\n0 2 0 0 4 0 0 6 0 0 8 0 0\n)\n%\n(\nE\nC\nP\nT\nC\nao r gn et\nr\nto\nl\nT i m e ( h )\nISOS-L-1 at ~15% RH\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nResponse to reviewers’ comments\nFor Reviewer #2:\nRemarks to the Author\nThe manuscript addresses a relevant challenge in the upscaling of perovskite solar cells (PSCs), namely\nthe degradation mechanisms associated with the P1 scribe in monolithic perovskite solar modules\n(PSMs). While several previous studies have focused on stability issues linked to the P2 and P3 scribes,\nsuch as direct contact of perovskite with electrodes and exposure to ambient conditions. The authors\naim to highlight the often-overlooked role of the P1 scribe. They propose that the difference in substrate\ncomposition at the P1 depression (Glass/CTL vs ITO/CTL) alters perovskite crystallization kinetics,\nwhich in turn could affect device stability. An additive engineering strategy is introduced to mitigate\nthis. Although the literature does discuss coating and stability issues related to the P1 scribe\nindividually, the perovskite crystallization behavior at this trench and its stability together is not well\nstudied.\nIt is well established, particularly in lab-scale, small-area devices, that perovskite crystallizes\ndifferently on Glass/CTL and ITO/CTL, as also demonstrated by the contrast between scribed and non-\nscribed areas in this study. Additive strategies, including 2D materials, are commonly used in large-\narea devices to enhance uniform crystallization and passivate defects across the active area, including\nthe P1 region. This makes the manuscript’s novelty relatively limited in terms of the perovskite\ncrystallization perspective.\nThe topic is of potential interest to the perovskite community, particularly if the link between\ncrystallinity in the P1 scribe region and overall module stability can be clearly established. However,\nthe current version of the manuscript lacks conclusive evidence to support this central claim. In\nparticular, the presented stability data does not sufficiently isolate the impact of the P1 scribe from\nother contributing factors. Several of the characterizations are performed on films rather than full\ndevices, and stability comparisons are primarily made between small-area and large-area devices rather\nthan between control and target PSMs with and without additive strategies.\nGiven the limited novelty and the lack of definitive evidence that the observed stability improvements\nare specifically due to mitigation at the P1 scribe, I am not able to recommend the manuscript for\npublication. I encourage the authors to consider the following specific suggestions to strengthen the\nmanuscript:\nReply: Many thanks for the reviewer for their thorough evaluation and valuable insights. We\nacknowledge that perovskite crystallization differences on various substrates (Glass/CTL vs. ITO/CTL)\nand the use of additives (including 2D materials) for uniform coating and defect passivation in large-\narea devices are established concepts. However, our work provides significant novel insights\nspecifically into P1-scribe related degradation mechanisms and their mitigation, which we believe\naddresses a critical gap.\nFirst of all, we demonstrate that the distinct perovskite crystallization behavior within the P1 trench\narises from the synergistic effect of confined crystallization (geometric constraint) and substrate\ndifference (Glass/CTL vs. ITO/CTL). This combination creates a unique local environment not fully\ncaptured by studying flat Glass/CTL or ITO/CTL alone. Crucially, we establish a direct link between\nthis localized P1 crystallization non-uniformity and accelerated module degradation, which is different\nfrom the P2/P3 issue. The new data (Supplementary Fig. 35-37) shows the SEM characterization of\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nthe perovskite buried interface in the P1 scribe area under light soaking over time in overall modules.\nThis reveals obvious morphological degradation (e.g., voids) initiating specifically at the P1 lines,\nthereby providing conclusive evidence that in addition to P2/P3, the crystallization difference of P1\nscribe area is also an important degradation pathway. To further validate this finding at the device level\nand directly correlate the localized morphology changes with overall performance degradation, we\nsubsequently compared the degradation rates of small-area devices fabricated on customized substrates\n(with P1 etching) and those on conventional ITO substrates (Supplementary Fig. 34, 38d). The results\nclearly demonstrate that after approximately 800 hours of light soaking under 1-sun illumination, the\ndevices on customized substrates (with P1 etching) exhibited a significantly faster degradation rate\ncompared to those on conventional substrates. This accelerated performance degradation strongly\nsuggests that the P1 scribing itself introduces vulnerable sites that accelerate device degradation.\nThen, while additives are common, our work employs a specific 2D additive engineered to\nfundamentally alter crystallization kinetics. This specific additive was chosen because DJ-phase\nperovskites with diammonium spacers form strong hydrogen bonds between both ends of the spacer\nand adjacent inorganic octahedral layers, significantly enhancing structural stability and promoting\nin-plane charge transport. Additionally, the presence of carbon-carbon double bond further improves\ncharge carrier mobility and structural ordering. While shorter spacers generally yield higher\nperformance, they often compromise stability compared to longer counterparts (Science, 2022, 375,\n71-76; J. Am. Chem. Soc., 2025, 147, 17926-17935). Therefore, after balancing conductivity and\nstability, we selected (E)-But-2-ene-1,4-diamine dihydrochloride as the additive for the perovskite\nprecursor solution. We demonstrate it induces a switch from top-down crystallization (control,\nSupplementary Fig. 11) to bottom-up quasi-epitaxial growth templated from a 2D layer at the bottom\ninterface (target, Supplementary Fig. 24). This bottom-up growth mode significantly improves\noverall film crystallinity (Supplementary Fig. 24f). More importantly, it greatly improved the\nuniformity specifically around the P1 scribe lines (Supplementary Fig. 25, 29), directly addressing\nthe identified P1 problem.\nFinally, we fully agree that it is crucial to clearly distinguish the additive engineering. Fig. 5 has\nbeen revised to directly compare the stability of control PSMs (without additive) versus target PSMs\n(with 2D additive) under identical conditions, including P1, P2, and P3 scribing. The revised stability\ndata demonstrates that the target PSMs exhibit significantly enhanced long-term stability, which is\nentirely attributed to the crystallization and stability improvement around the P1scribe area achieved\nthrough the bottom-up quasi-epitaxial growth mechanism.\nOur research provides a novel mechanistic understanding of the P1 scribe related degradation, and\ndemonstrates a targeted strategy based on additive engineering to control the crystallization kinetics\nthrough bottom-up quasi-epitaxial growth. We believe that these findings offer significant\ncontributions to understanding and alleviating the degradation to perovskite modules.\nMajor Comments:\n1. Comments: The statement that “primary loss arises from a reduction in the fill factor (FF) due to\ndecreased perovskite crystal uniformity” should be rephrased to reflect that other factor such as\nincreased series resistance, shunt paths, and contact resistance, can also contribute significantly to FF\nlosses during scaling.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nReply: We sincerely thank the reviewer for this insightful comment. The reviewer pointed out that\nfactors beyond perovskite crystal uniformity, such as increased series resistance, shunt paths, and\ncontact resistance, can indeed play significant roles in contributing to fill factor (FF) losses during\ndevice scaling. We agree that our original statement could be interpreted as attributing primary FF loss\nsolely to reduced perovskite uniformity, which was not our intended emphasis.\nTo address this point fully and improve the accuracy of our discussion, we have revised the relevant\nsentence in the manuscript. Specifically, we have rephrased it to explicitly acknowledge these\nadditional critical factors influencing FF during scaling. The text now clearly states that: “And other\nfactor such as increased series resistance, shunt paths, and contact resistance, can also contribute\nsignificantly to FF losses during scaling.” We believe this modification significantly strengthens the\ndiscussion and appreciate the reviewer for highlighting this important aspect.\n2. Comments: Most of the stability data compares small-area to large-area devices, while the\nmanuscript’s main focus is on mitigating P1-related degradation in PSMs. A more appropriate\ncomparison would be between control and target large-area devices. Although EQE-EL measurements\nare presented under dark, controlled conditions, they may not capture the full degradation pathway.\nThe rationale behind choosing this method over continuous maximum power point (MPP) tracking\nunder light exposure should be clearly discussed.\nReply: Thank you very much for your constructive suggestions. We fully agree that comparing control\nand target large-area devices is most relevant for perovskite solar modules (PSMs). Fig. 5 has been\nrevised to directly compare the stability of control PSMs versus target PSMs.\nWe have added continuous maximum power point tracking (MPPT) tracking data under light\nexposure comparing control and target PSMs (Fig. 5f). This operational stability test confirms the\nenhanced resilience of our target devices. The long-term operational stability of the unencapsulated\nmodules base on control and target is also tested with MPPT under 1-sun illumination at 25 °C with a\nN flow and full solar illumination, as depicted in Fig. 5f. After 360 hours of continuous illumination,\n2\nthe control and target module retained approximately 43.9% and 98.6% of their initial efficiencies,\nrespectively.\nThe long-term stability of modules (with an aperture area of 25 cm2) is evaluated using EL-EQE\ntracking based on the ISOS-D-1 protocol. It can be demonstrated that the defects related to non-\nradiation losses in the perovskite absorber are significantly suppressed by the BDECl process. As\nshown in the original submitted manuscript (Supplementary Fig. 16), we have compared the PCE\nevolution over time of unencapsulated PSMs based on control and target with an aperture area of 25\ncm2 under 1-sun illumination with a white light-emitting diode (100 mW cm−2) in ambient air with\n~15% RH at room temperature according to ISOS-L-1, and have replaced it with Fig. 5e.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nFig. 5| Photovoltaic performance of small-area PSCs and large-area PSMs. a, J-V characteristics\nof the champion PSCs based on control and target with an aperture area of 0.102 cm2. b, c, J-V\ncharacteristics of the champion PSMs based on control and target with aperture area of 25 cm2 (b) and\n100 cm2 (c). d, EL-EQE evolution curves on the control and target modules over time. Devices were\nperiodically tested from 1 V to 2.5 V, with each step being 0.1 V. e, PCE evolution over time of\nunencapsulated PSMs based on control and target with an aperture area of 25 cm2 under 1-sun\nillumination with a white light-emitting diode (100 mW cm−2) in ambient air with ~15% RH at room\ntemperature according to ISOS-L-1.f, Continuous maximum power point tracking of the control and\ntarget PSMs (25 cm2) fabricated under 1-sun illumination with a white light-emitting diode\n(100 mW cm−2) at 25 °C with a N flow. g, The long-term stability of unencapsulated PSCs (0.102 cm2)\n2\nand PSMs (25 cm2) fabricated with the target in ambient air with ~15% RH at room temperature\naccording to ISOS-D-1. Devices were periodically tested under AM 1.5G irradiation with a Xe arc\nlamp at 100 mW cm−2. Data presented as mean ± s.d. in d, e, and g, tracing the PCE of ten devices over\ntime for each condition.\n3. Comments: In Supplementary Figure 16b, the authors show ISOS-L1 stability tests, but it remains\nunclear how they decouple the specific contribution of P1 from broader effects of additive engineering,\nwhich can affect crystallization and passivation across the bulk and interfaces (including P2 and P3\nregions). The manuscript would benefit from a more detailed explanation or supporting experiments\nto isolate the role of P1 from other mechanisms.\nReply: We appreciate the reviewer’s insightful comment regarding the need to decouple P1-specific\neffects from the broader benefits of additive engineering. We fully acknowledge that BDECl enhances\ncrystallization and passivation globally, including the bulk perovskite, interfaces, and non-P1 regions\n(\n(\n(\n(\na\nd\nf\n)\n)\n)\n)\n)\n)\n2\n-m\nc\nA\nm\n(\ny\nt\nis\nn\ne\nd\nt\nn\ne\nr\nr\nu\nC\n)\n)\n%\n(\nE\nQ\nE\n-\nL\nE\n)\n)\n%\n(\nE\nC\nP\n)\n)\n(\nb\n)\n4\n2\n-\nm\n2\n5\nc\nC\no\nn\nt\nr\no\nl\nT\na\nr\ng\ne\nt\nA\n3\n2\na\nrg\ne\nt\nm\nF\no\nrw\nard\nF\no\nrw\nard\n(\nC\no\nn\ntro\nl\nT\na\np\ne\nr\ntu\nre\na\nre\na\n:\n2\nis\nV\n1.18V\n1.19V\n2\nn\n2\n5\nc\nm\nO\nC\n1\n0\ne\n-\n2\n-\n25.02m\nA\ncm\n26.06m\nA\ncm\nd\nP\nC\nE\nV\nJ\nF\nF\nS\nC\nC\nS\nC\nt\n(%\n)\n-\n2\n(V)\n(m\nA\ncm\n)\n(%\n)\n5\nn\nF\nF\n82.82%\n83.85%\ne\nTarget\n8.24\n3.73\n80.43\n24.70\nr\nP\nC\nE\n24.54%\n26.05%\nControl8.01\n3.60\n78.85\n22.76\nr\n0\n0\nuC\n-\n0\n.\n2\n0\n.\n0\n0\n.\n2\n0\n.\n4\n0\n.\n6\n0\n.\n8\n1\n.\n0\n1\n.\n2\n0\n1\n2\n3\n4\n5\n6\no\nlta\ng\ne\n(V\n)\nV\no\nlta\ng\ne\n(V\n)\n(\ne\n)\n2\n4\n7\n.\n2\n3\n%\n8\n2\n0\n6\n)%\n1\n6\n(\n1\n2\n1\n.\n7\n5\n%\n2\nT\na\nrg\ne\nt\n0\nO\nS\n-\nD\n-\n1\na\nt\n~\n1\n5\n%\nR\nH\nC\no\nn\ntro\nl\n0\n-\n2\n0\n0\n2\n0\n0\n4\n0\n0\n6\n0\n0\n8\n0\n0\n1\n0\n0\nim\ne\n(h\n)\n(\ng\n)\n2\n4\n2\n6\n2\n2\n.\n8\n2\n%\n2\n0\n2\n4\n)%\n1\n6\n2\n2\n(\nE\n1\n2\n2\n9\n.\n0\n0\n%\nP\n8\n1\nO\nS\n-\nL\n-\nT\na\nrg\ne\nt\n4\n1\n6\na\nt\n1\n-\ns\nu\nn\nli\ng\nh\nt\ns\no\na\nk\nin\ng\nC\no\nn\ntro\nl\n0\n0\n0\n5\n0\n1\n0\n0\n1\n5\n0\n2\n0\n0\n2\n5\n0\n3\n0\n0\n3\n5\nim\ne\n(h\n)\n)\n(\nc\n)\n2\n-\nm\nc\nA\nm\n(\ny\nt\nis\nn\ne\nd\nt\nn\ne\nr\nr\nu\nC\n)\na\nrg\ne\nt\nC\no\nn\ntro\nl\n5\n0\ne\nv\nic\ne\nM\no\nd\nu\nle\n5\n0\n0\n1\n0\n3\n2\n2\n1\n1\n0\n0\n0\n.\ne\nrt\nifi\ne\nd\ne\nff\nic\nie\nn\nc\ny\n:\n2\n3\n.\n5\n5\n%\n.\na\nrg\ne\nt\n.\no\nn\ntro\nl\nA\np\ne\nr\ntu\nre\na\nre\na\n:\n.\n2\n1\n0\n0\nc\nm\n.\nC\nE\nV\nJ\nF\nF\nO\nC\nS\nC\n(%\n)\n-\n2\n(V)\n(m\nA\ncm\n)\n(%\n)\n.\n2.68\n76.19\n23.89\nControl11.36\n2.52\n72.88\n20.83\n.\n0\n-\n2\n0\n2\n4\n6\n8\n1\n0\n1\no\nlta\ng\ne\n(V\n)\n9\n1\n.\n3\n3\n%\n8\n3\n.\n4\n9\n%\nIS\nO\nS\n-\nL\n-\n1\na\nt\n~\n1\n5\n%\nR\nH\n1\n0\n0\n0\n1\n5\n0\n0\n2\n0\n0\n0\n2\n5\nim\ne\n(h\n)\n9\n6\n.\n7\n7\n%\n9\n3\n.\n8\n0\n%\nIS\nO\nS\n-\nD\n-\n1\na\nt\n~\n1\n5\n%\nR\nH\n0\n1\n5\n0\n0\n2\n0\n0\n0\n2\n5\n0\n0\n3\n0\n0\nim\ne\n(h\n)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\n(e.g., P2/P3) (Supplementary Fig. 11f, 24f).\nSupplementary Fig. 11 | Grazing incidence x-ray diffraction (GIXRD) measurement on control\nFAPbI films. a-f, GIXRD patterns (vertically offset for clarity, * denotes the peaks from the FAI-\n2 3\ns, (d) 30 s, (e) 60 s, and (f) 600 s.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 24 | GIXRD measurement on target FAPbI films. a-f, GIXRD patterns\n3\n(vertically offset for clarity, * denotes the peaks from the FAI-PbI -NMP intermediate phase, # denotes\n2\nthe peaks from the 2D perovskite intermediate phase at the bottom of the FAPbI films annealed for\n3\ndifferent times: (a) 0 s, (b) 1 s, (c) 3 s, (d) 30 s, (e) 60 s, and (f) 600 s.\nSEM characterization (Supplementary Fig. 35-37) reveals that BDECl specifically improves\nburied interface morphology and uniformity at the P1 scribe lines in modules. Target devices show\nmarkedly reduced defects in the P1 area versus controls.\nSupplementary Fig. 35 | Schematic representation of peeling the perovskite films from perovskite\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nmodules with an UV glue for SEM characterization. The electron beam comes from the bottom.\nSupplementary Fig. 36 | SEM images of the bottom surface of the control perovskite films in the\nnon-scribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions\nfor different time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis.\n(\n(\n(\n(\na\nb\nc\nd\n)\n)\n)\n)\n0 h\n2 0 μ m\n2 4 h\n2 0 μ m\n7 2 h\n2 0 μ m\n1 2 0 h\n2 0 μ m\nN o n\n2 μ m\nN o n\n2 μ m\nN o n\n2 μ m\nN o n\n2 μ m\n-\ns\n-\ns\n-\ns\n-\ns\nc\nc\nc\nc\nr ib\nr ib\nr ib\nr ib\ne\ne\ne\ne\na\na\na\na\nr e\nr e\nr e\nr e\na\na\na\na\nS c\n2 μ\nS c\n2 μ\nS c\n2 μ\nS c\n2 μ\nr ib\nm\nr ib\nm\nr ib\nm\nr ib\nm\ne\ne\ne\ne\na\na\na\na\nr e\nr e\nr e\nr e\na\na\na\na\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\n(a) 0 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(b) 24 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(c)\n72 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(d)\n120 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\nSupplementary Fig. 37 | SEM images of the bottom surface of the target perovskite films in the non-\nscribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions for\ndifferent time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis. The grain boundary grooves observed in the scribe area are\ncaused by the protrusions formed during the laser etching to the redeposition of the ITO.\nFurthermore, to verify the specific contribution of BDECl towards improving perovskite\ncrystallization within the P1 scribe areas, we analyzed the performance of the device on the customized\nsubstrate (Supplementary Fig. 38). Supplementary Fig. 38d clearly shows the significantly\nenhanced photovoltaic stability of the target devices (with BDECl) compared to the control devices\n(without BDECl) under light soaking (ISOS-L-1) in low-humidity (~15% RH) ambient conditions.\nThis superior stability is closely associated with BDECl's suppression of overall device defects.\nThe electroluminescence (EL) images provided in Supplementary Fig. 39 offer further visual evidence:\nboth in the initial state and after 792 hours of light aging, the target devices exhibited more uniform\nand stronger EL intensity across the entire active area, including the critical vicinity of the P1 scribe\nline. In contrast, the control devices exhibited significant unevenness (dark spots) and intensity\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\ndegradation after aging, particularly around the P1 scribe area. These results strongly indicate that the\nBDECl additive not only improves the stability of the bulk perovskite but also improves the uneven\nfilm deposition caused by the P1 etching area, suppressing non-radiative recombination in these areas.\nConsequently, this leads to a significant enhancement in the overall device performance and long-term\noperational stability.\nSupplementary Fig. 38 | a, Schematic illustration of the customized substrate after laser scribing. b,\nc, Photograph of the customized substrate (b) and the small-area device (c, aperture area of 0.1 cm2).\nd, PCE evolution over time of unencapsulated PSCs based on control and target with an aperture area\nof 0.1 cm2 under 1-sun illumination with a white light-emitting diode (100 mW cm−2) in ambient air\nwith ~15% RH at room temperature according to ISOS-L-1.\nSupplementary Fig. 39 | a, Electroluminescence (EL) images of the control and target PSCs on the\ncustomized substrate. b, After 792 hours of light aging, electroluminescence (EL) images of the control\nand target PSCs on the customized substrate under 1-sun illumination with a white light-emitting diode\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\n(100 mW cm−2) in ambient air with ~15% RH at room temperature according to ISOS-L-1.\nThese data collectively demonstrate the overall passivating effect of BDECl and its specific\ncontribution to the P1 etching area.\n4. Comments: To convincingly attribute improvements to P1 perovskite degradation mitigation,\nadditional characterization is necessary. PL imaging, SAM, XRD, or cross-sectional TEM analyses\nlocalized around the P1, P2, and P3 regions after stability testing (control vs target) would greatly\nenhance the claim. Without this, it's difficult to isolate P1 as the dominant degradation pathway for\nPSMs.\nReply: We appreciate the reviewer's suggestion for advanced localized characterization and agree that\nisolating degradation pathways is crucial. While we acknowledge P2/P3’s established role in module\ndegradation (ACS Applied Materials & Interfaces, 2019, 11, 45646-45655; ACS Energy Letters, 2018,\n3, 322-328; Advanced Materials, 2020, 33, 2006170), our data robustly demonstrates that P1 serves as\na critical degradation initiation site, and its mitigation is central to our stability improvements.\nFig. 2a (Optical Microscopy) and 2b (PL mapping) reveal intrinsically poorer perovskite film\nquality (e.g., voids, reduced PL intensity) specifically within the P1 scribe before any aging, indicating\nits inherent vulnerability. At the same time, after aging, the quality of the perovskite film around the\netching area began to gradually deteriorate.\nSecondly, we have added in-situ OM for the perovskite films in a high-humidity environment and\nunder illumination. Exposure to high-humidity conditions (~70% RH) accelerated the degradation of\nperovskite films (Supplementary Fig. 7a). Through in-situ optical microscopy (OM) characterization,\nit is observed that the perovskite film in the scribe area almost completely degraded after 24 hours\n(Supplementary Fig. 7b).\nSupplementary Fig. 7 | a, Photograph of the in-situ OM testing of the perovskite film under high-\nhumidity environment (~70% RH) at room temperature. b, In-situ OM images of evolutions of the\nperovskite film over time around the P1 scribe line under high-humidity environment.\nThe degradation process of perovskite films under 1-sun illumination are tracked using in-situ\noptical microscopy (OM) (Supplementary Fig. 8). It indicates that the freshly prepared perovskite\nfilm exhibits uniform morphology, while significant changes are already observable in the scribe area\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nafter 24 hours of illumination. After 80 hours, pronounced color differences become apparent around\nthe scribe line.\nSupplementary Fig. 8 | a, Photograph of the in-situ OM testing of the perovskite film under 1-sun\nillumination with a white light-emitting diode (100 mW cm−2) in ambient air with ~15% RH at room\ntemperature. b, In-situ OM images of evolutions of the perovskite film over time around the P1 scribe\nline under 1-sun illumination.\nWe will peel off the perovskite film in the module (Supplementary Fig. 35). we conducted a test\non the SEM images of the control perovskite module exposed to 1-sun illumination (Supplementary\nFig. 36). It can be clearly observed that after 120 hours, the scribe area of the control module has\nbasically been damaged, and the perovskite films near the etched areas will be affected.\nSupplementary Fig. 35 | Schematic representation of peeling the perovskite films from perovskite\nmodules with an UV glue for SEM characterization. The electron beam comes from the bottom.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 36 | SEM images of the bottom surface of the control perovskite films in the\nnon-scribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions\nfor different time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis.\nSubsequently, we compared the degradation rates of small-area devices fabricated on customized\nsubstrates (with P1 etching) and those on conventional ITO substrates (Supplementary Fig. 34, 38d).\nThe results clearly demonstrate that after approximately 800 hours of light soaking under 1-sun\nillumination, the devices on customized substrates (with P1 etching) exhibited a significantly faster\ndegradation rate compared to those on conventional substrates. This accelerated performance\ndegradation strongly suggests that the P1 scribing itself introduces vulnerable sites that accelerate\ndevice degradation.\n(\n(\n(\n(\na\nb\nc\nd\n)\n)\n)\n)\n0 h\n2 0 μ m\n2 4 h\n2 0 μ m\n7 2 h\n2 0 μ m\n1 2 0 h\n2 0 μ m\nN o n\n2 μ m\nN o n\n2 μ m\nN o n\n2 μ m\nN o n\n2 μ m\n-\ns\n-\ns\n-\ns\n-\ns\nc\nc\nc\nc\nr ib\nr ib\nr ib\nr ib\ne\ne\ne\ne\na\na\na\na\nr e\nr e\nr e\nr e\na\na\na\na\nS c\n2 μ\nS c\n2 μ\nS c\n2 μ\nS c\n2 μ\nr ib\nm\nr ib\nm\nr ib\nm\nr ib\nm\ne\ne\ne\ne\na\na\na\na\nr e\nr e\nr e\nr e\na\na\na\na\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 34 | PCE evolution over time of unencapsulated PSCs based on control and\ntarget with an aperture area of 0.102 cm2 under 1-sun illumination with a white light-emitting\ndiode (100 mW cm−2) in ambient air with ~15% RH at room temperature according to ISOS-L-\n1. Devices were periodically tested under AM 1.5G irradiation with a Xe arc lamp at 100 mW cm−2.\nData presented as mean ± s.d., tracing the PCE of ten devices over time for each condition.\nSupplementary Fig. 38 | a, Schematic illustration of the customized substrate after laser scribing. b,\nc, Photograph of the customized substrate (b) and the small-area device (c, aperture area of 0.1 cm2).\nd, PCE evolution over time of unencapsulated PSCs based on control and target with an aperture area\nof 0.1 cm2 under 1-sun illumination with a white light-emitting diode (100 mW cm−2) in ambient air\nwith ~15% RH at room temperature according to ISOS-L-1.\nThis combined evidence consistently demonstrates that the P1 laser etched area, due to its inferior\nperovskite crystallinity, acts as a dominant degradation initiation site.\n5. Comments: Figures 1-4 primarily examine perovskite films deposited on substrates, whereas in real\ndevices the P1 region is a buried interface. Environmental exposure is therefore not equivalent.\nCharacterizing P1 degradation in complete module stacks would be more relevant.\nReply: We sincerely appreciate the reviewer’s insightful critique regarding the environmental\nexposure difference between perovskite films on substrates versus in real devices. In the complete\nmodule, the P1 region is a buried interface. The reviewer is absolutely correct that degradation\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nmechanisms at buried interfaces under operational conditions are critical to assess. We acknowledge\nthat the study of isolated films alone cannot fully replace the degradation kinetics in modules.\nHowever, direct characterization of the buried P1 region in complete modules faces two key\nchallenges. The perovskite layer is embedded within the multilayer stack\n(glass/ITO/ETL/perovskite/HTL/electrode). The P1 scribed area is electrically inactive (\"dead zone\"),\npreventing standard in-situ electro-optical probing.\nTo directly address this concern while overcoming these constraints, we will peel off the\nperovskite film in the module (Supplementary Fig. 35). we conducted a test on the SEM images of\nthe control perovskite module exposed to 1-sun illumination (Supplementary Fig. 36). It can be\nclearly observed that after 120 hours, the scribe area of the control module has basically been\ndamaged, and the perovskite films near the etched areas will be affected.\nSupplementary Fig. 35 | Schematic representation of peeling the perovskite films from perovskite\nmodules with an UV glue for SEM characterization. The electron beam comes from the bottom.\n(\n(\na\nb\n)\n)\n0 h\n2 0 μ m\n2 4 h\n2 0 μ m\nN o n\n2 μ m\nN o n\n2 μ m\n-\ns\n-\ns\nc\nc\nr ib\nr ib\ne\ne\na\na\nr e\nr e\na\na\nS c\n2 μ\nS c\n2 μ\nr\nm\nr\nm\nib\nib\ne\ne\na\na\nr\nr\ne\ne\na\na\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 36 | SEM images of the bottom surface of the control perovskite films in the\nnon-scribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions\nfor different time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis.\nAdding BDECl to the perovskite precursor solution enhances both defect suppression and chemical\nstability, resulting in markedly improved PSMs stability (Supplementary Fig. 37).\n(\n(\nc\nd\n)\n)\n7\n2 0\n1\n2 0\n2 h\nμ m\n2 0 h\nμ m\nN o\n2 μ\nN o\n2 μ\nn\nm\nn\nm\n-\ns\n-\ns\nc\nc\nr\nr\nib\nib\ne\ne\na\na\nr\nr\ne\ne\na\na\nS c\n2 μ\nS c\n2 μ\nr ib\nm\nr ib\nm\ne\ne\na\na\nr e\nr e\na\na\n(a) 0 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(b) 24 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 37 | SEM images of the bottom surface of the target perovskite films in the non-\nscribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions for\ndifferent time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis. The grain boundary grooves observed in the scribe area are\ncaused by the protrusions formed during the laser etching to the redeposition of the ITO.\n6. Comments: In SI Figure 7C, even non-scribed areas on the ETL show significant δ-phase formation,\nsuggesting that crystallization and degradation are not limited to P1 scribe regions, where target\nsamples may be benefited due the passivation at buried interface due to addtive. This raises questions\nabout the specificity of the additive’s impact on P1 and indicates that other degradation pathways\n(selection of configuration n-i-p or p-i-n, CTLs etc.) may be equally or more important.\nReply: We appreciate the reviewer's insightful comment regarding the potential for additive effects\nbeyond the P1 scribe regions and the importance of other degradation pathways. We agree that the\nadditive (BDECl) likely provides beneficial passivation effects throughout the perovskite film, not\nsolely confined to the P1 scribe lines. This is corroborated by the improved overall film crystallization\nobserved in target samples, as shown in Supplementary Fig. 24f.\n(\n(\nc\nd\n)\n)\n7\n2\n1\n2\n2 h\n0 μ m\n2 0 h\n0 μ m\nN\n2\no\nμ\no\nμ\nn\nm\nn\nm\n-\n-\ns\ns\nc\nc\nr\nr\nib\nib\ne\ne\na\na\nr\nr\ne\ne\na\na\nS\n2\nc\nμ\nc\nμ\nr\nm\nr\nm\nib\nib\ne\ne\na\na\nr\nr\ne\ne\na\na\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 24 | GIXRD measurement on target FAPbI films. a-f, GIXRD patterns\n3\n(vertically offset for clarity, * denotes the peaks from the FAI-PbI -NMP intermediate phase, # denotes\n2\nthe peaks from the 2D perovskite intermediate phase at the bottom of the FAPbI films annealed for\n3\ndifferent times: (a) 0 s, (b) 1 s, (c) 3 s, (d) 30 s, (e) 60 s, and (f) 600 s.\nHowever, our data strongly indicates that the P1 scribe region presents a particularly vulnerable site\nfor degradation initiation. Firstly, SEM characterization reveals significantly worse perovskite\nmorphology and stability in the scribe areas compared to non-scribed areas, both in films and mini-\nmodules (Supplementary Fig. 9, 36). Then, the devices fabricated on the customized substrate with\nP1 scribe lines exhibit significantly lower PCE and stability compared to control devices on the non-\nscribed substrates (Supplementary Fig. 38, 39). Critically, degradation in modules initiates at the P1\nscribe lines. Optimizing this scribe region is therefore paramount for stability, regardless of the n-i-p\nor p-i-n configuration.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\n(a) 0 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(b)\n2 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(c) 7 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(d)\n24 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(e)\n48 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(f)\n72 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 9 | SEM images of the control perovskite film in the non-scribe area and the\nscribe area in ambient air with ~15% RH and at room temperature under 1-sun illumination\nwith different times: (a) 0 hour, (b) 2 hours, (c) 7 hours, (d) 24 hours, (e) 48 hours, (f) 72 hours, and\n(g) 120 hours.\nSupplementary Fig. 36 | SEM images of the bottom surface of the control perovskite films in the\nnon-scribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions\nfor different time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis.\n(\n(\n(\ng\na\nb\n)\n)\n)\n1 2 0 h\n2 0 μ m\n0 h\n2 0 μ m\n2 4 h\n2 0 μ m\nN o n\n2 μ m\nN o n\n2 μ m\nN o n\n2 μ m\n-\ns\n-\ns\n-\ns\nc\nc\nc\nr ib\nr ib\nr ib\ne\ne\ne\na\na\na\nr e\nr e\nr e\na\na\na\nS c\n2 μ\nS c\n2 μ\nS c\n2 μ\nr\nm\nr\nm\nr\nm\nib\nib\nib\ne\ne\ne\na\na\na\nr\nr\nr\ne\ne\ne\na\na\na\n(c)\n72 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(d) 120 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 38 | a, Schematic illustration of the customized substrate after laser scribing. b,\nc, Photograph of the customized substrate (b) and the small-area device (c, aperture area of 0.1 cm2).\nd, PCE evolution over time of unencapsulated PSCs based on control and target with an aperture area\nof 0.1 cm2 under 1-sun illumination with a white light-emitting diode (100 mW cm−2) in ambient air\nwith ~15% RH at room temperature according to ISOS-L-1.\nSupplementary Fig. 39 | a, Electroluminescence (EL) images of the control and target PSCs on the\ncustomized substrate. b, After 792 hours of light aging, electroluminescence (EL) images of the control\nand target PSCs on the customized substrate under 1-sun illumination with a white light-emitting diode\n(100 mW cm−2) in ambient air with ~15% RH at room temperature according to ISOS-L-1.\nMeanwhile, the reviewer rightly points out the significance of device architecture (n-i-p vs. p-i-n)\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nand charge transport layers (CTLs) on stability. Our study focuses on the n-i-p structure because we\nemployed the FAPbI₃ precursor solution. This system demonstrates superior performance in n-i-p\narchitectures compared to p-i-n architectures, particularly in achieving higher PCEs. While\ndegradation mechanisms certainly differ between n-i-p and p-i-n structures, and CTLs can introduce\ninstability factors, our core finding remains: within the chosen high-performing n-i-p system, the P1\nscribe line is a critical degradation origin, and BDECl can effectively alleviate the degradation of the\nperovskite.\nThe reviewer correctly notes that as shown in Supplementary Fig. 7c, even non-scribed areas on\nthe ETL show significant δ-phase formation, suggesting that crystallization and degradation are not\nlimited to P1 scribe regions. We agree that the ETL can affect the stability of the cover layer perovskite\nfilm, as evidenced by the data and literature (Energy Environ. Sci., 2022, 15, 4836-4849). However,\nthe specific sample configuration depicted in Supplementary Figure 7C does not represent an actual\ndevice structure used or studied in our work. Consequently, we acknowledge that including this data\nwas misleading in the context of our study and will remove Supplementary Fig. 7c from the\nmanuscript (Supplementary Fig. 18, Revised).\nSupplementary Fig. 18 | Degradation process of the perovskite films on the customized substrates.\na, Schematic illustration of the laser scribing process and the customized substrate after laser scribing.\nb, XRD patterns of the perovskite films in the non-scribe area and the scribe area.\nIn summary, while BDECl enhances bulk perovskite stability, it plays a crucial role in specifically\nimproving the uniformity of the perovskite films in the P1 area, thereby preventing degradation\ninitiation at this critical site, is strongly supported by our morphological, performance, and aging data\non scribed vs. non-scribed substrates and mini-modules.\n7. Comments: The influence of substrate variation (Glass/CTL vs ITO/CTL) may also apply to small-\narea devices due to edge effects. It would be useful to discuss this and how it might influence perovskite\ncrystallization and degradation at the ITO/glass boundary, even in 0.1 cm² devices.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nReply: We thank the reviewer for raising the important point regarding potential edge effects (Glass\nvs. ITO) influencing perovskite crystallization and degradation at boundaries, even in small-area\ndevices. To specifically probe the influence of the laser-etched glass surface within the P1 scribes\ncompared to the ITO surface, we used the substrates of small-area devices containing both the non-\nscribe area (ITO) and the scribe area (Glass). Optical microscopy confirms a significantly increased\nsurface roughness on the scribe area (Glass) compared to the non-scribe area (ITO) (Supplementary\nFig. 17b). XRD and SEM analysis of perovskite films deposited on these substrates reveal that the\ncrystallinity and film quality on the scribe area (Glass) are slightly inferior compared to those formed\non the smoother ITO surfaces (Supplementary Fig. 17c, d).\nSupplementary Fig. 17 | a, Schematic diagrams for the FAPbI film on different substrates: ITO and\n3\nbare glass, respectively. b, OM images of the surface morphology of ITO and bare glass. c, d, XRD\npattern (vertically offset for clarity) (c) and Top-view SEM (d) of the FAPbI film deposited on ITO\n3\nor bare glass.\nThese results demonstrate that substrate variation directly influences perovskite crystallization\nquality, even on small-area substrates. The observed edge effects are therefore crucial factors\ncontributing to the differences in film formation and potentially long-term stability at these scribe\nboundaries.\n8. Comments: Figure 1f would benefit from higher magnification to clearly show void formation.\nAdditionally, the SEM images suggest the perovskite layer appears planar, whereas profilometry\nindicates a trench in the P1 area. Clarification is needed, especially given the depth mismatch between\nthe depression (from profilometer) and film thickness (from SEM).\nReply: Thanks to the reviewers for the suggestions. The high-resolution scanning electron microscope\nimages related to Fig. 1 have also been submitted along with the revised manuscript files. The standard\ntop-view SEM provides a two-dimensional projection of the surface morphology and inherently lacks\nthe ability to convey height information or depth perception. This limitation explains why the\nperovskite layer appears planar in top-view images, even over the P1 area where a trench exists.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nCrucially, cross-sectional SEM analysis (provided in the original manuscript) confirms the trench\nstructure. Specifically, it shows the intact ITO thickness (~170 nm) in non-etched regions and the\ndistinct depression within the P1 etched area. This measured depth within the P1 trench from cross-\nsectional SEM is fully consistent with the step profiler data presented in Supplementary Fig. 12.\nSupplementary Fig. 12 | Step profiler of nanosecond laser scribing and femtosecond laser\nscribing. By nanosecond laser scribing (a) and femtosecond laser scribing (b), the depth at the P1\nscribe line and the depth at the P1 scribe line after printing the SnO layer and the SnO /perovskite\n2 2\nlayers, respectively.\n9. Comments: Contact angle measurements on bare glass (SI Figure 6) may not reflect device-relevant\nsurfaces, which include CTLs. Without surface treatment like UV-ozone, glass generally shows higher\ncontact angles, so linking this to crystallization in P1 needs more contextual justification.\nReply: We are grateful to the reviewers for their valuable comments regarding the correlation of\ncontact angles measured on bare glass. To directly address this issue and ensure that the measurement\nresults can reflect the surface conditions relevant to the device, we have performed contact angle\nmeasurements of the perovskite precursor solution on plasma-treated SnO₂-coated substrate and on\nplasma-treated substrate. Although the contact angles between the non-scribe area and the scribe area\nof the substrate remained almost the same after plasma treatment (Supplementary Fig. 16c), it is\nimpossible to eliminate the increase in roughness caused by laser etching (Supplementary Fig. 17b).\nDue to the edge effect on small-area substrates, the uniformity of the perovskite films differs between\nthe ITO/Glass substrates and the bare glass substrates (Supplementary Fig. 17c, d). The perovskite\nfilms deposited on smooth ITO/Glass substrates exhibit enhanced crystallinity and reduced defect\ndensity.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 16 | Wettability differences between the non-scribe area and the scribe area.\na, Schematic illustration of the contact angle measurement setup in the P1 scribe area. b, Contact\nangles of water and perovskite precursor solution on the untreated (no plasma) ITO substrate around\nthe non-scribe area and the scribe area, respectively. c, Contact angles of perovskite precursor solution\non the plasma treated substrate and the plasma treated substrate/SnO around the non-scribe area and\n2\nthe scribe area, respectively.\nSupplementary Fig. 17 | a, Schematic diagrams for the FAPbI film on different substrates: ITO and\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nbare glass, respectively. b, OM images of the surface morphology of ITO and bare glass. c, d, XRD\npattern (vertically offset for clarity) (c) and Top-view SEM (d) of the FAPbI film deposited on ITO\n3\nor bare glass.\nThis new data provides direct evidence that differences in wettability, as measured by contact angle\non the relevant module surface with plasma treatment, are negligible between the scribe area and non-\nscribe area. However, the increase in substrate roughness caused by laser etching will be an important\nfactor contributing to the crystalline differences.\n10. Comments: Details on laser scribing parameters (GFF, scribe width, laser type) and the proportion\nof active vs dead area would enhance reproducibility and contextual understanding of the results,\nespecially since the work aims to address stability linked to P1 scribe geometry.\nReply: We appreciate the reviewer's valuable suggestion to enhance the reproducibility of our work.\nWe have now comprehensively documented all P1 laser processing details and quantified the scribe\nline quality through new experimental evidence. In the supplementary information, we have provided\ndetailed information about the lasers (including nanosecond lasers and femtosecond lasers), and have\nalso explanations regarding the laser parameters used for P1 etching during the preparation of the\nperovskite module (Supplementary Note 2-3). In addition, the surface morphology of the ITO\nsubstrate after P1 etching was characterized using an optical microscope (Supplementary Fig. 1).\nSupplementary Fig. 1 | Optical microscope (OM) images of the surface morphology of the ITO\nsubstrate around the scribe area after laser scribing with: (a) nanosecond pulsed laser and (b)\nfemtosecond pulsed laser.\nThese additions provide essential experimental context and significantly improve the reproducibility\nof our module fabrication process, particularly regarding the critical link between P1 scribe geometry\nand device stability emphasized in this study.\n11. Comments: Given known stability issues of ETLs in n–i–p architectures, it would be helpful to\nexplain the choice of this structure over p–i–n. If p–i–n devices were also investigated, including their\nresults would provide a broader perspective. The role of Al₂O₃ nanoparticles in p–i–n devices\n(mentioned briefly) should also be clarified.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nReply: We thank the reviewer for raising this important point regarding architecture selection and\nAl₂O₃ functionality. Our choice of the n-i-p structure was driven by three primary considerations: First,\nwe intentionally employed the FAPbI₃ precursor solution to avoid phase segregation issues inherent in\nmixed-cation perovskites. This system demonstrates superior performance in n-i-p architectures\ncompared to p-i-n architectures, particularly in achieving higher PCEs. Given the demonstrated\nperformance advantages of FAPbI₃ in the n-i-p device, optimizing this architecture offered greater\nscientific and practical significance for our scaling study. Notwithstanding our primary focus, we\nconducted validation experiments in p-i-n structures (Supplementary Fig. 19a, 28, 45, and 46). These\nconfirm the general applicability of our key findings across architectures.\nAccording to the literature (Science, 2023, 379, 683–690), the ultra-thin Al₂O₃ layer acts as an\nintermediate layer with low conductivity, which can enhance the wettability of the perovskite precursor\nsolution on the HTL, and at the same time forms a porous insulator contact (PIC) structure PIC reduces\nnonradiative recombination at perovskite’s HTL contact through a combined effect of contact area\nreduction and passivation.\n12. Comments: In Figure 1b, the labels should read \"device (PSC)\" vs \"module (PSM)\" instead of\n\"control\" vs \"target.\" Please revise for clarity.\nReply: Thanks to the reviewers for pointing out the labeling error in Fig. 1b. The use of “control” vs.\n“target” was indeed inadvertently incorrect. We have now revised the figure labels to accurately reflect\n“device” and “module” as suggested. This correction improves the clarity and precision of the figure\ndescription. The updated figure has been implemented in the revised manuscript.\nb, The stability of devices (0.102 cm2) and modules (25 cm2) in ambient air with ~15% relative\nhumidity (RH) and at room temperature according to ISOS-D-1.\n13. Comments: The manuscript mentions localized XRD at the P1 scribe, which is <50 µm wide.\nMore information is needed on how such high spatial resolution was achieved and whether any beam\nbroadening or signal overlap from adjacent regions might affect the accuracy.\nReply: We thank the reviewer for raising this important point regarding the spatial resolution of our\nlocalized XRD measurements on the narrow P1 scribe (<50 µm). We acknowledge the valid concerns\nabout beam broadening and potential signal overlap from adjacent regions.\nTo specifically characterize the perovskite film formation within the P1 scribe area, we employed a\ncustomized substrate for these XRD measurements. Instead of measuring isolated P1 scribes on a\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nmodule substrate, we fabricated a dedicated test substrate where the ITO was patterned with periodic\nP1 scribes (~50 µm wide) spaced approximately 2 mm apart, covering the entire substrate area. This\ndesign successfully mimics the film crystallization within the P1 scribe area of the module. This\nmethod allowed us to probe the crystallinity of the perovskite film specifically formed within the P1\nscribe area.\na, Schematic illustration of the customized substrate after laser scribing. b, Custom substrate coated\nwith perovskite film by blade coating, cut into a 15×15 mm sample for XRD characterization.\nThe work addresses an underexplored aspect of PSM stability related to P1 scribe-induced\ncrystallization inhomogeneity. The conceptual link is interesting, and the strategy of additive\nengineering aligns with current trends in module-scale optimization. However, the present data does\nnot definitively isolate P1-related degradation or convincingly demonstrate that the additive strategy\nimproves long-term stability through P1 mitigation alone. Additional characterizations and a more\nfocused experimental design could significantly enhance the manuscript. I hope the authors find these\nsuggestions constructive in refining their work.\nReply: We sincerely thank the reviewer for this constructive summary and for acknowledging the\nunderexplored nature of P1-related degradation and the interest in our conceptual approach. We agree\nthat definitively isolating the P1-related degradation pathway is crucial. To address this core concern\nand directly demonstrate that our additive strategy improves long-term stability specifically through\nP1 mitigation, we have conducted key additional experiments:\nFirst, to conclusively link module stability to the P1 etching, we performed Top-view SEM\ncharacterization of the buried interface of perovskite films peeled from fully processed modules after\nlight exposure. This localized analysis reveals that severe void formation occurs specifically within\nthe P1 scribe of the control modules (Supplementary Fig. 36), which directly correlates with their\nrapid performance decline. In contrast, the target modules with BDECl additive maintain a uniform,\nvoid-free perovskite morphology in the P1 region even after extended light exposure (Supplementary\nFig. 37). This demonstrates that the improved long-term stability is achieved by preventing\ndegradation initiation at the vulnerable P1 site.\nFurthermore, to definitively isolate the impact of the P1 scribe itself on performance, we designed\na custom substrate with P1 scribes for small-area device testing (Supplementary Fig. 38). The stability\nresults from these devices show that the presence of the laser-etched P1 scribe alone accelerates the\nefficiency degradation rate compared to devices without P1 etching. This experiment isolates the P1\neffect from other module-specific factors and confirms it as an inherent stability weak point.\nWe believe these additional data provide a much more focused and definitive line of evidence. They\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nconvincingly demonstrate that: the P1 scribe is a critical degradation initiation point, and our additive\nengineering strategy delivers its long-term stability benefit primarily by mitigating degradation\nspecifically in the P1 scribe area, thereby solidifying our central claim.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nResponse to reviewers’ comments\nFor Reviewer #3:\nRemarks to the Author\nThis manuscript addresses a relevant and important topic on PSM stability, focusing specifically on\nthe effect of P1 laser scribing. The authors show that P1 laser scribing negatively impacts the stability\nof PSMs by introducing defects (PbI₂, voids, δ-phase perovskite) due to confinement crystallization.\nThey address this by using BDECl additive, significantly improving film quality, module performance,\nand stability. The approach, combining optical characterization and morphology analysis, is valuable.\nHowever, the manuscript lacks critical experimental details, clear data presentation, and evidence\nsupporting key claims. Several key figures have poor resolution or insufficient clarity, making\ninterpretation difficult. While this study addresses important issues, the evidence presented is\ninsufficient to support the conclusions, and the presentation also requires significant improvement. I\nrecommend Major Revision. The authors should add missing experimental details, improve data\npresentation, and perform additional measurements or include controls to validate their claims. The\nfollowing specific comments and recommended changes that need to be addressed to strengthen the\nmanuscript.\nReply: We are grateful to the reviewer for acknowledging the significance of our work on P1 laser-\ninduced instability in perovskite solar modules (PSMs) and for recognizing the value of our BDECl-\nbased additive engineering approach. We sincerely appreciate the constructive critique regarding\ninsufficient experimental details, data presentation clarity, and evidentiary support for key claims. In\nresponse, we have meticulously revised the manuscript to address these concerns comprehensively.\n1. Comments: The manuscript lacks detail on the laser processing parameters used for P1 (e.g., laser\nwavelength, pulse duration, fluence, scan speed, film side or substrate side illumination? etc.)\nAdditionally, the uniformity and quality of the P1 lines (morphology surface and cross-section, OM\nimages, presence of residual ITO or debris) are not described. This is very important because the\nimpact of P1 on module stability can vary significantly depending on the scribing conditions.\nReply: We thank the reviewer for emphasizing the critical impact of laser scribing parameters on\nmodule stability. We have now comprehensively documented all P1 laser processing details and\nquantified the scribe line quality through new experimental evidence. In the supplementary\ninformation, we have provided detailed information about the lasers (including nanosecond lasers and\nfemtosecond lasers), and have also explanations regarding the laser parameters used for P1 etching\nduring the preparation of the perovskite module (Supplementary Note 2-3).\nIn addition, the surface morphology of the ITO substrate after P1 etching was characterized using\nan optical microscope (Supplementary Fig. 1), which showed that after the substrate was cleaned,\nthere were almost no debris around the scribe lines.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 1 | Optical microscope (OM) images of the surface morphology of the ITO\nsubstrate around the scribe area after laser scribing with: (a) nanosecond pulsed laser and (b)\nfemtosecond pulsed laser.\nHowever, due to the melting and subsequent deposition of the ITO material, the surface of the scribe\narea became relatively rough, with some small protrusions. This can be seen from the step profiler\nmeasurement in Supplementary Fig. 12.\nSupplementary Fig. 12 | Step profiler of nanosecond laser scribing and femtosecond laser\nscribing. By nanosecond laser scribing (a) and femtosecond laser scribing (b), the depth at the P1\nscribe line and the depth at the P1 scribe line after printing the SnO layer and the SnO /perovskite\n2 2\nlayers, respectively.\n2. Comments: Could varying the P1 conditions improve grain formation in the scribed areas as well?\nIt is essential to present grain growth results across a broader range of P1 conditions. Showing only\ntwo cases is insufficient and does not adequately support the conclusions drawn.\nReply: We appreciate the reviewer's insightful suggestion regarding the potential impact of varied P1\nconditions on grain formation in scribed areas. To thoroughly address this, we systematically tested a\nwide range of laser scribing widths (300 μm, 500 μm, and 1000 μm) under optimized fluence (100\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nKHz) and scan speed (300 mm s-1) conditions.\nSupplementary Fig. 20 | a, OM images of the surface morphology of the ITO substrate around the\nscribe area after laser scribing with different widths: 300 μm, 500 μm, and 1000 μm. b, Lower\nmagnification SEM image of perovskite film around the P1 scribe line with different scribing widths:\n300 μm, 500 μm, and 1000 μm. c, d, SEM images of fresh perovskite films in the non-scribe area (c)\nand the scribe area (d) with different scribing widths: 300 μm, 500 μm, and 1000 μm.\nAs demonstrated in Supplementary Fig. 20, SEM characterization of perovskite films deposited on\nthese substrates reveals a consistent trend: regardless of the width of the lines, there are obvious holes\nin the perovskite film around the laser scribe area. Critically, even at the maximal 1000 μm width\n(approaching the practical limit for module design), we observed no improvement in crystallinity or\ndefect density. This confirms that the redeposition of ITO material during the ITO laser ablation\nprocess leads to a significant increase in the roughness of the scribe area, which is the cause of grain\ngrowth defects. Consequently, the adjustment of laser parameters cannot solve the inherent\ncrystallization defects of perovskite. This limitation underscores the necessity of our BDECl additive\napproach, which actively optimize the crystallization of the perovskite in this area (Fig. 4b), rather\nthan relying on passive laser optimization.\n(\n(\n(\n(\na\nb\nc\nd\n)\n)\n)\n)\nW id t h\n3 0 0 μ m\nW id t h\n3 0 0 μ m\n1 0 0 μ m\nW id t h\n3 0 0 μ m\n2 μ m\nW id t h\n3 0 0 μ m\n2 μ m\n=\n=\n=\n=\nN o n -s\nS\nc\nc\nr\nr\nib\nib\ne\ne\na\na\nr e\nr e\na\na\nW id t h\n5 0 0 μ m\nW id t h\n5 0 0 μ m\n2 0 0 μ m\nW id t h\n5 0 0 μ m\n2 μ m\nW id t h\n5 0 0 μ m\n2 μ m\n=\n=\n=\n=\nN o n -s\nS\nc\nc\nr\nr\nib\nib\ne\ne\na\na\nr\nr\ne\ne\na\na\nW id t h\n1 0 0 0 μ\nW id t h\n1 0 0 0 μ\n2 0 0 μ m\nW id t h\n1 0 0 0 μ\n2 μ m\nW id t h\n1 0 0 0 μ\n2 μ m\n=m\n=m\n=m\n=m\nN o n -s\nS\nc\nc\nr ib\nr ib\ne\ne\na\na\nr e\nr e\na\na\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\n3. Comments: The aging conditions and experimental environments of the various samples appear to\nbe inconsistent throughout the manuscript. Can the authors explain why these conditions are not\nstandardized? Also, descriptions such as “low humidity and low oxygen” are not sufficiently precise.\nPlease provide precise numbers.\nReply: We acknowledge the reviewer's valid concern regarding the description of aging conditions\nand thank them for prompting us to clarify this critical aspect. The apparent variations in experimental\nenvironments were intentionally designed to probe degradation mechanisms under distinct stressors:\naccelerated aging tests employed elevated humidity (~70% RH) or continuous illumination (1 sun,\nAM1.5G) to induce rapid failure modes relevant to real-world operation, while fundamental\ndegradation studies used controlled low-humidity conditions (~15% RH) in ambient air at room\ntemperature. All conditions are now rigorously quantified in the revised manuscript.\n4. Comments: The authors attribute the decrease in module efficiency primarily to a reduction in FF.\nCould you specify whether this reduction is mainly influenced by series or shunt resistance?\nAdditionally, were Jsc and Voc unaffected by degradation? It would be helpful to present time-\ndependent J–V curves clearly demonstrating the evolution of these parameters. (If PbI₂ formation\nindeed occurs, Voc also decrease)\nReply: We thank the reviewer for this insightful inquiry regarding the efficiency loss mechanism in\nscaled modules. We believe that the dominant factor driving fill factor (FF) reduction is the significant\ndecrease in shunt resistance (Rsh), primarily attributable to defect proliferation in large-area perovskite\nfilms-manifested as pinholes, grain boundary disorders, and unpassivated interfaces. These defects\nintensify non-radiative recombination, elevating leakage currents that directly degrade Rsh. While\nseries resistance (Rs) also increases due to ITO sheet resistance scaling and interconnect “dead zones”,\nits contribution to FF loss is secondary.\nThe decline in the uniformity of the film is the fundamental cause. Large-area perovskite films are\nprone to issues such as holes, uneven thickness, and crystalline defects, which are the root causes of\nthe deterioration in resistance. We have plotted the J-V curves of the perovskite devices and modules\nas the area increases (from 0.102 cm² to 100 cm²), and presented them in Supplementary Fig. 2.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 2 | J-V characteristics of the control PSCs and PSMs with different aperture\nareas: (a) 0.102 cm2, (b) 1.01 cm2, (c) 25 cm2, and (d) 100 cm2.\nCritically, both open-circuit voltage (Voc) and short-circuit current density (Jsc) exhibit declines\nwith area scaling (Voc: 1.18 V → 1.13 V; Jsc: 25.09 → 24.74 mA cm-² for 0.102 cm² → 100 cm²,\nSupplementary Fig. 3), though FF remains the most severely impacted parameter (82.20% →\n71.49%). While PbI₂ accumulation and pinholes in scribed area minimally affect initial PCE (as\nelectrically isolated dead zones), they act as degradation nucleation sites. Under operation, ion\nmigration from these zones propagates defects into active areas, accelerating PCE decay over time.\nSupplementary Fig. 3 | Statistical distributions of photovoltaic parameters with different\naperture areas from 0.102 cm2 to 100 cm2. (a) V , (b) J , (c) FF, and (d) PCE.\nOC SC\n5. Comments: What evidence is presented for PbI₂ formation? In Figure 2e, the claim might be that\nthere are bright or contrast features in an SEM or some mapping indicating PbI₂, but the image\nresolution is low and not clearly explained.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nReply: We thank the reviewer for requesting clarification regarding the evidence for PbI₂ formation.\nOur identification of PbI₂ is substantiated by multi-modal characterization:\nFirst, high-resolution SEM imaging (Fig. 1d, 3b, et al.) consistently reveals that white sheet-like\ncrystals are clearly visible at the grain boundaries of the perovskite film after 10 minutes of annealing,\nindicating the presence of PbI (Joule, 2022, 6, 2869-2884; Nat Commun, 2024, 15, 9703; Science,\n2\n2021, 372, 1327-1332; Adv. Mater., 2025, e11124; Adv. Energy Mater., 2025, 2502696). Second,\nGIWAXS data (Fig. 3c) explicitly detects the PbI₂ diffraction peak at q = 0.895 Å⁻¹ after 450 s\nz\nannealing, confirming its out-of-plane growth. Then, the SAED pattern (Fig. 3d) along the [421̅] zone\nC\naxis suggests that the perovskite film in the scribe area is hexagonal PbI .\nof perovskite films in the scribed area exhibited characteristic peaks at 1366 cm⁻¹ (Pb-I lattice vibration)\nand 1712 cm⁻¹ (C=N⁺ stretching of FA⁺) with significantly enhanced and attenuated intensities,\nrespectively. This indicates that the content of PbI is higher in this area, while the content of FA+ is\n2\nlower.\nSupplementary Fig. 15 | Fourier transform infrared microscopy (Micro-FTIR) of the control\nperovskite film around the P1 scribe line. a, OM image of the perovskite film around the scribe line.\nb, c, Two-dimensional IR mapping images of the perovskite film around the scribe line at wavelengths\nof (b) 1366 cm-1 and (c) 1712 cm-1. The red box of (a) indicates the test area. The red color indicates\nthat the peak signal at this wavelength is relatively strong, while the green color denotes a\ncomparatively weak peak signal at the corresponding wavelength. d, Fourier transform infrared\nspectrum (FTIR) of the perovskite film in the non-scribe area and the scribe area. The yellow circle of\n(a) represents the test area.\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nTo address concerns regarding resolution: All the scanning electron microscope images in the text\nare provided in the form of high-resolution files. Collectively, these cross-validated techniques\ndemonstrate unequivocal PbI₂ enrichment in scribed zones, with morphological, crystallographic, and\nspectroscopic signatures consistent across independent methods.\n6. Comments: On page 7, the authors state that \"the perovskite in the P1 scribe region is almost\ncompletely decomposed, and the decomposed region begins to diffuse into the non-scribed region.\"\nThe current manuscript lacks clear visual data showing this decomposition diffusion, so clear and\nconvincing image-based evidence should be presented.\nReply: We appreciate the reviewer’s request for visual evidence supporting the degradation diffusion\nfrom scribe area to non-scribe area. Firstly, Fig. 2a clearly illustrates the gradual expansion of the\ntransparent area starting from the P1 scribe line and extending to adjacent regions. This expansion of\nthe light-transmitting range directly indicates the decomposition and diffusion phenomenon of the\nperovskite. Fig. 2b quantitatively depicts the local photoluminescence decay around the scribe line\nunder accelerated aging conditions (relative humidity of 70%). Within 15 minutes, it is clearly\nobserved that the fluorescence lifetime of the perovskite around the scribe line continuously decreases\n(from red to green).\nMeanwhile, as stated in the main text, the perovskite films in the scribe area have poor crystallinity\n(with voids and enrichment of lead iodide). These defects create accelerated degradation pathways.\nFinally, we conducted a test on the SEM images of the perovskite module exposed to 1-sun\nillumination (Supplementary Fig. 36). It can be clearly observed that after 120 hours, the scribe area of the\nmodule has basically been damaged, and the perovskite films near the etched areas will be affected,\nleading to the collapse of the perovskite crystal structure.\n(a) 0 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\n(b) 24 h Non-scribe area Scribe area\n20 μm 2 μm 2 μm\nInstitute of Polymers and Energy Chemistry (IPEC)\nCollege of Chemistry and Chemical Engineering\nNanchang University\n南昌大学高分子能源与化学研究院/化学化工学院\n南昌市红谷滩新区学府大道 999 号，邮编 330031\nSupplementary Fig. 36 | SEM images of the bottom surface of the control perovskite films in the\nnon-scribe area and the scribe area. Perovskite modules are illuminated under AM 1.5G conditions\nfor different time: (a) 0 hour, (b) 24 hours, (c) 72 hours, and (d) 120 hours, after which the perovskite\nfilms are detached for further analysis.\nThe combined OM, PL, and SEM data establish a clear spatial-temporal progression: decomposition\ninitiates in defect-rich scribe areas and radially diffuses into non-scribe areas via defect pathways.\n7. Comments: In Figure 2, the OM images exhibit color changes; can you clarify what these color\ndifferences indicate? Additionally, why were different measurement conditions used for OM and PL\ndata?\nReply: We appreciate the reviewer’s insightful questions regarding Figure 2 and are pleased to clarify\nthese points. These OM images (Fig. 2a) were obtained through the transmission (bottom) white light\nillumination method. At the initial state (t ), the yellow area represents the complete perovskite film.\ndark brown spots (verified by the Micro-FTIR). The partially transparent etched area indicates an\ninitial poor form (with holes), thereby allowing light to penetrate. After 20 days (t + 20 days), the\n0\nlight transmittance of the etched area increased, indicating that the perovskite had completely degraded.\nThe optical microscope was conducted in ambient air (25 °C, ~15% RH) to track long-term\ndegradation kinetics under realistic storage conditions (20 days). In-situ two-dimensional PL mapping\nwas performed under accelerated degradation conditions (85% RH, 25 °C) to capture in-situ\ndegradation process within a practical timeframe.\n8. Comments: Do the authors have stability results regarding the impact of P2 and P3 scribing\nprocesses? It would be beneficial to refer to the recent study by Jeong et al. (Solar RRL, 2024"}]

Decision letter