Impact of the Top Electrode Material on the Stability of Inverted Lead Halide Perovskite Solar Cells: A Comparative Study

Top electrodes play a vital role in perovskite solar cells (PSCs) by enabling efficient electron extraction and transport, which significantly influences the device efficiency and operational stability under harsh environmental conditions. This work presents a systematic investigation of different electrodes, such as aluminum (Al), silver (Ag), cobalt (Co), chromium (Cr), nickel (Ni), and titanium (Ti), by the thermal evaporation technique in inverted‐PSCs. From the experimental evidence, the devices based on Al, Ag, Ni, Cr, Ti, and Co exhibited a power conversion efficiency of ~15.4%, 13.0%, 13.3%, 11.7%, 12.0%, and 11.6%, respectively. Most importantly, the Ti electrode exhibited excellent stability under continuous light exposure for 1200 h without any encapsulation, attributed to suppression of diffusion into the MAPbI ₃ /WO _{3− x} layer, preventing pitting and void defects. Therefore, Ti is an ideal top electrode material for p–i–n devices. Our findings emphasize that MAPbI ₃ /WO _{3− x} /Ti stands as the most stable interface reported for p–i–n PSCs under harsh aging conditions.