Pulsatile therapy for perovskite solar cells

The current top challenge for the commercialization of perovskite solar cells is to ensure long-term stability. Herein, we developed pulsatile therapy, which can revive the degraded device and eventually prolong device lifetime by addressing the accumulation of both charges and ions in the middle of maximum power point tracking (MPPT). In this technique, reverse biases are repeatedly applied for a short time to eliminate the charges accumulated and redistribute the ions that have migrated during power harvesting without any pause of operation. Intriguingly, the therapy is not only delaying irreversible degradation but also restoring the degraded power right after a short reverse bias. In situ measurements of photoluminescence intensity and photocurrent dynamics during the therapy confirmed that newly formed defects could be annihilated as a result of discharging and ion redistribution, featuring suppression of defect formation and irreversible degradation. In the long-term test, we observed outstanding improvement of device stability and total harvesting energy.