Abstract：
Stability is the most pressing challenge hindering the commercialization of perovskite solar cells (PSCs), and previous efforts focused more on enhancing the resistance of PSCs to external stimulus. Here, we found that the indium tin oxide (ITO) will deteriorate the photovoltaic performance of PSCs through positive feedback cycles. Specifically, the perovskite degradation products will cross the electron transport layer to chemically etch the electrode ITO to generate In3+, which will migrate upwards into the perovskite film. Then, the reaction that corrodes ITO consumes the decomposition products of perovskite and shifts the balance of the perovskite decomposition reaction, further promoting the degradation and thus falling into a positive feedback cycle. Moreover, the In3+ in the perovskite film was found to accumulate at the upper surface, which would lead to n-type doping of perovskite film to form the energy barrier for interface carrier extraction. Subsequently, the chelating molecule ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) was introduced onto ITO to firmly chelate the In3+ and prevent it from migrating upward, thus breaking this internal positive feedback cycle and significantly enhancing the efficiency and stability of PSCs. This work provides new perspectives for understanding the mechanism of photovoltaic performance loss and ionic transport in PSCs.
摘要：
稳定性是阻碍钙钛矿太阳能电池（PSC）商业化的最紧迫挑战，以前的努力更多地集中在增强PSC对外部刺激的抵抗力上。这里,我们发现，氧化铟锡（ITO）会通过正反馈循环恶化PSC的光伏性能。具体来说,钙钛矿降解产物将穿过电子传输层以化学蚀刻电极ITO以产生In3+，它将向上迁移到钙钛矿薄膜中。然后，腐蚀ITO的反应消耗钙钛矿的分解产物，并改变钙钛矿分解反应的平衡，进一步促进降解，从而陷入正反馈循环。此外，发现钙钛矿薄膜中的In3+积聚在上表面，这将导致钙钛矿薄膜的n型掺杂，形成界面载流子提取的能量势垒。随后，将螯合分子乙二胺四乙酸二钠盐(EDTA-2Na)引入到ITO上，牢固地螯合In3+，防止其向上迁移，从而打破这种内部正反馈循环，并显着提高PSC的效率和稳定性。这项工作为理解PSC中光伏性能损失和离子传输的机制提供了新的视角。
