Efficient Perovskite Solar Modules Enabled by Synergistic Interparticle and Interfacial Electrostatic Interaction Regulation

Chemical bath deposition (CBD) has proved to be a reliable method for fabricating SnO 2 electron transport layers for perovskite solar modules, yet the critical nanoparticle−nanoparticle and nanoparticle−substrate interactions governing uniform film formation remain insufficiently understood. Here, we demonstrate a synergistic electrostatic interaction regulation strategy that simultaneously modulates colloidal stability among nanoparticles and enhances their binding affinity to the fluorine-doped tin oxide substrate during CBD. This method enables controlled assembly of SnO 2 nanoparticles and promotes continuous film formation over large areas. The resulting perovskite solar cells (active area 0.0727 cm 2 ) achieve a power conversion efficiency of 26.47% (26.03% certified) with a remarkable fill factor of 85.6%, representing one of the highest performances reported to date for perovskite solar cells employing CBD-derived SnO 2 . More importantly, this strategy markedly mitigates efficiency loss when increasing the size of the devices, yielding an efficiency of 24.70% for a 1 cm 2 device and over 21% for a solar module with an active area of 65.24 cm 2 .