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 SnO2 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 SnO2 nanoparticles and promotes continuous film formation over large areas. The resulting perovskite solar cells (active area 0.0727 cm2) 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 SnO2. More importantly, this strategy markedly mitigates efficiency loss when increasing the size of the devices, yielding an efficiency of 24.70% for a 1 cm2 device and over 21% for a solar module with an active area of 65.24 cm2.