Fu Sheng, Le Jiabo, Guo Xueming, Sun Nannan, Zhang Wenxiao, Song Weijie, Fang Junfeng
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
School of Physics and Electronic Science, Engineering Research Center of Nanophotonics & Advanced Instrument, Ministry of Education, East China Normal University, Shanghai, 200241, China.
Adv Mater. 2022 Sep;34(38):e2205066. doi: 10.1002/adma.202205066. Epub 2022 Aug 22.
Triiodide cesium lead perovskite (CsPbI ) has promising prospects in the development of efficient and stable photovoltaics in both single-junction and tandem structures. However, achieving inverted devices that provide good stability and are compatible to tandem devices remains a challenge, and the deep insights are still not understood. This study finds that the surface components of CsPbI are intrinsically lead-poor and the relevant traps are of p-type with localized states. These deep-energy-level p traps induce inferior transfer or electrons and serious nonradiative recombination at the CsPbI /PCBM interface, leading to the considerable open-circuit voltage (V ) loss and reduction of fill factor (FF). Compared to molecular passivation, polishing treatment with 1,4-butanediamine can eliminate the nonstoichiometric components and root these intrinsically lead-poor traps for superior electron transfer. The polishing treatment significantly improves the FF and V of the inverted CsPbI photovoltaics, creating an efficiency promotion from 12.64% to 19.84%. Moreover, 95% of the initial efficiency of the optimized devices is maintained after the output operation for 1000 h.
三碘化铯铅钙钛矿（CsPbI₃）在单结和串联结构的高效稳定光伏器件开发中具有广阔前景。然而，实现具有良好稳定性且与串联器件兼容的倒置器件仍然是一项挑战，目前仍缺乏深入了解。本研究发现，CsPbI₃的表面成分本质上贫铅，相关陷阱为具有局域态的p型。这些深能级p陷阱导致电子转移不良以及CsPbI₃/PCBM界面处严重的非辐射复合，从而导致可观的开路电压（V₀c）损失和填充因子（FF）降低。与分子钝化相比，用1,4 - 丁二胺进行抛光处理可以消除非化学计量成分并根除这些本质上贫铅的陷阱，以实现优异的电子转移。该抛光处理显著提高了倒置CsPbI₃光伏器件的FF和V₀c，使效率从12.64%提升至19.84%。此外，优化后的器件在输出运行1000小时后仍保持初始效率的95%。
