Suppressing Potential‐Induced Degradation in Perovskite Solar Cells Through Sodium‐Free Substrate

Perovskite solar cells (PSCs) are a promising photovoltaic (PV) technology due to their superior power conversion efficiency (PCE). However, potential‐induced degradation (PID) has been recognized as a critical issue in contemporary commercial solar systems, impeding reliability and commercialization. The migration of sodium (Na) ions from substrates is considered a key contributor to the PID of PV technologies under high‐voltage stress conditions. Strategies for mitigating or suppressing PID remain underexplored in PSCs. Here, for the first time, an approach using a Na‐free substrate is introduced to suppress the PID of PSCs under high humidity and elevated temperature, aligned with standard testing conditions (ICE 62804−1). It is demonstrated that Na‐free glass‐based devices maintained 91% of their initial PCE, while soda‐lime glass (SLG)‐based retained only 52%. After extended testing (1056 h), Na‐free glass‐based devices retained 96.61% of their initial PCE at 25°C and 60% relative humidity, outperforming SLG‐based devices, which failed entirely after 576 h. Na‐free glass‐based devices recovered 99.6% of their initial PCE after 96 h of post‐PID dark storage and retained 96.44% after 3072 h. These findings provide a pathway to accelerate the commercialization of PSCs.