Du Yu, Wan Sushu, Xie Mingcai, Xia Yuren, Yang Weiqing, Wei Zhihong, Zhu Yajie, Hua Yan, Jin Zhong, Hong Daocheng, Tian Yuxi
Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China.
Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, China.
J Phys Chem Lett. 2021 Aug 5;12(30):7106-7112. doi: 10.1021/acs.jpclett.1c01803. Epub 2021 Jul 23.
Ionic movement inside organometal halide perovskites (OMHP) materials has been widely reported to be linked with stability issues in the perovskite-based optoelectronic devices. However, the dynamic processes of the ionic movement and how they influence the devices are still not well-understood. In this work, we applied an external electric field to the CHNHPbI crystal and simultaneously monitored the PL behaviors. Two successive PL responses were observed in the same location of the crystal. First, an irreversible PL quenching was observed caused by the photo-annealing effect under an electric field accompanied by a permanent morphology change. The annealed area also showed reversible PL variation, which was attributed to the activation-deactivation of the radiative recombination centers induced by the migration of the iodine ions. Such results can help us gain a deep insight into how the ionic movements in OMHPs influence the performance of the perovskite-based optoelectronic devices under working conditions.
据广泛报道，有机金属卤化物钙钛矿（OMHP）材料内部的离子运动与基于钙钛矿的光电器件中的稳定性问题有关。然而，离子运动的动态过程以及它们如何影响器件仍未得到很好的理解。在这项工作中，我们对CHNHPbI晶体施加了外部电场，并同时监测了光致发光（PL）行为。在晶体的同一位置观察到了两个连续的PL响应。首先，在电场下由于光退火效应观察到不可逆的PL猝灭，同时伴随着永久性的形貌变化。退火区域还显示出可逆的PL变化，这归因于碘离子迁移引起的辐射复合中心的激活-失活。这些结果有助于我们深入了解OMHPs中的离子运动如何在工作条件下影响基于钙钛矿的光电器件的性能。
