Holistic Laser Scribing Strategy for Perovskite Modules: Coupled P1–P2–P3 Optimization toward Low CTM Loss and Improved Stability

Perovskite solar modules have drawn wide attention for their high efficiency and cost-effective fabrication, yet the transition from cells to modules remains challenging. Laser scribing is essential for monolithic integration. While previous studies have focused on optimizing laser parameters, this work elucidates how laser-scribing conditions influence film morphology and electrical properties, and their correlation with device performance and stability. For the P1 process, we reveal that laser-induced microstructural modification determines subsequent film quality. By introducing a "two-line overlap" strategy, we form a less dense SnO2 layer near the 1st line, which is suggested to provide a pathway for Na diffusion from the substrate. This is proposed to contribute to defect passivation in the perovskite solar cell, thereby improving stability. In the P2 process, optimized laser power and scanning speed minimize contact resistance, and a "three-line overlap" strategy further increases the interconnection area, thereby reducing Rs and improving the fill factor (FF). In P3, low laser pulse overlap and power prevent excessive perovskite exposure, contributing to device stability. Through this integrated optimization, we achieve perovskite mini modules with a low cell-to-module loss of 2.2% and negligible efficiency degradation over 30 days under dark ambient storage. These results highlight that controlling laser-induced microstructure and electrical changes is key to stable perovskite photovoltaics.