Investigation of potential-induced degradation and recovery in perovskite minimodules

Potential-induced degradation (PID) is a prevalent concern in current commercial photovoltaic technologies that impacts their reliability, with the mechanistic basis for PID being poorly understood. Here we investigate the PID mechanism in perovskite minimodules. Our findings reveal non-uniform degradation in both the photoluminescence intensity and spectral blue shift. Following 60-hour laboratory stress tests, device efficiency drastically decreases by 96%, and the shunt resistance decreases by 97%, accompanied by a significant quantity of Na+ ions (derived from the soda-lime glass) throughout the device structure, leading to a typical PID shunting effect. Interestingly, we observed a rapid recovery of device performance during room-temperature dark storage, in which Na+ ions located close to the glass substrate side rapidly migrate out of the device. Moreover, we also found that the Na+ ions do not appear to diffuse through the grain boundaries but rather their neighboring area and grain interiors, judging by microscopic conductivity mappings.