Assessing degradation in perovskite solar cells via thermal hysteresis of photocurrent and device simulation

Understanding the degradation mechanisms of perovskite solar cell (PSC) is paramount to addressing stabilityrelated issues. Photocurrent loss is widely observed in the degraded PSC. Here, we investigate the degradation of PSC by probing the thermal hysteresis of photocurrent (THPC) and the dynamics of thermally active ionic or recombination processes. Degraded devices exhibit a considerably higher degree of variation in the photogenerated current, encompassing a broad spectrum of photo-induced ionic charge accumulation. THPC reveals changes driven by the accumulation of interfacial ionic charges and active defects under photo-thermal drifting, as supported by capacitance analysis. Device simulation corroborates that the interfacial surface defect formed at the interfacial layer in the device structure wields a substantial influence on device degradation, particularly in cases of photocurrent loss. This study underscores the direct correlation between the degradation of PSC and the presence of thermally activated traps and interfacial charge accumulation emphasizing the importance of passivating these pathways to improve device stability.