北京大学朱瑞团队提出钙钛矿表面化学抛光策略提高光伏性能。相关研究成果于2022年1月18日发表在《美国化学会杂志》。

钙钛矿太阳能电池（PSCs）中界面PbI₂的光不稳定性抵消了过量PbI₂对钙钛矿晶体成核和生长的好处。

该文中，研究人员报告了一种简单的化学抛光策略，将PbI₂晶体从钙钛矿表面剥离，以解耦这两种相反的效应。化学抛光产生了良好的钙钛矿表面，显示出增强的发光、延长的载流子寿命、抑制的离子迁移和更好的能级排列。这些期望的好处转化为增加的光电压和填充因子，从而产生高性能的介观结构甲脒碘化铅基PSCs，其最高效率为24.50%。

由于消除了以PbI₂晶体为主的界面离子迁移路径和光降解触发器，PSCs的迟滞被抑制，并且在光照或湿度应力下的器件稳定性显著提高。此外，新的表面抛光策略可以普遍适用于其他典型的钙钛矿结构。

附：英文原文

Title: Chemical Polishing of Perovskite Surface Enhances Photovoltaic Performances

Author: Lichen Zhao, Qiuyang Li, Cheng-Hung Hou, Shunde Li, Xiaoyu Yang, Jiang Wu, Siyang Zhang, Qin Hu, Yanju Wang, Yuzhuo Zhang, Yufeng Jiang, Shuang Jia, Jing-Jong Shyue, Thomas P. Russell, Qihuang Gong, Xiaoyong Hu, Rui Zhu

Issue&Volume: January 18, 2022

Abstract: The benefits of excess PbI2 on perovskite crystal nucleation and growth are countered by the photoinstability of interfacial PbI2 in perovskite solar cells (PSCs). Here we report a simple chemical polishing strategy to rip PbI2 crystals off the perovskite surface to decouple these two opposing effects. The chemical polishing results in a favorable perovskite surface exhibiting enhanced luminescence, prolonged carrier lifetimes, suppressed ion migration, and better energy level alignment. These desired benefits translate into increased photovoltages and fill factors, leading to high-performance mesostructured formamidinium lead iodide-based PSCs with a champion efficiency of 24.50%. As the interfacial ion migration paths and photodegradation triggers, dominated by PbI2 crystals, were eliminated, the hysteresis of the PSCs was suppressed and the device stability under illumination or humidity stress was significantly improved. Moreover, this new surface polishing strategy can be universally applicable to other typical perovskite compositions.

DOI: 10.1021/jacs.1c10842

Source: https://pubs.acs.org/doi/10.1021/jacs.1c10842