Beijing National Laboratory for Condensed Matter Physics, Renewable Energy Laboratory, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, 100190, P. R. China.
College of Materials Science and Opto-Electronic Technology, University Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Adv Mater. 2023 Jul;35(28):e2301879. doi: 10.1002/adma.202301879. Epub 2023 May 30.
Severe nonradiative recombination originating from interfacial defects together with the pervasive energy level mismatch at the interface remarkably limits the performance of CsPbI perovskite solar cells (PSCs). These issues need to be addressed urgently for high-performance cells and their applications. Herein, an interfacial gradient heterostructure based on low-temperature post-treatment of quaternary bromide salts for efficient CsPbI PSCs with an impressive efficiency of 21.31% and an extraordinary fill factor of 0.854 is demonstrated. Further investigation reveals that Br ions diffuse into the perovskite films to heal undercoordinated Pb and inhibit Pb cluster formation, thus suppressing nonradiative recombination in CsPbI . Meanwhile, a more compatible interfacial energy level alignment resulting from Br gradient distribution and organic cations surface termination is also achieved, hence promoting charge separation and collection. Consequently, the printed small-size cell with an efficiency of 20.28% and 12 cm printed CsPbI minimodules with a record efficiency of 16.60% are also demonstrated. Moreover, the unencapsulated CsPbI films and devices exhibit superior stability.
严重的非辐射复合源于界面缺陷，以及界面上普遍存在的能级失配，显著限制了钙钛矿太阳能电池（PSCs）的性能。这些问题需要紧急解决，以实现高性能电池及其应用。在此，通过低温后处理四溴化物盐，制备了基于界面梯度异质结的高效 CsPbI 钙钛矿太阳能电池，其效率高达 21.31%，填充因子高达 0.854。进一步的研究表明，Br 离子扩散到钙钛矿薄膜中，修复配位不足的 Pb 并抑制 Pb 团簇的形成，从而抑制 CsPbI 中的非辐射复合。同时，由于 Br 梯度分布和有机阳离子表面终止，实现了更兼容的界面能级排列，从而促进了电荷的分离和收集。因此，打印的小尺寸电池的效率为 20.28%，打印的 12cm CsPbI 微型模块的效率为 16.60%，也创下了记录。此外，未封装的 CsPbI 薄膜和器件表现出优异的稳定性。
