Du Yu, Wan Sushu, Pan Yanghang, Xie Mingyi, Ding Mengning, 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 Jan 21;12(2):773-780. doi: 10.1021/acs.jpclett.0c03322. Epub 2021 Jan 7.
Organometal halide perovskites (OMHPs) have emerged as advisible materials for application in optoelectronic devices over the past decade. However, a variety of complex slow responses in OMHPs under an external electric field have been observed, and the mechanisms for these responses remain a topic of intense debate. In this work, with an external voltage applied to the CHNHPbI crystal, reversible photoluminescence (PL) enhancement and quenching behaviors respectively near the anode and the cathode were observed under wide-field fluorescence microscopy. Further experiments attribute the reversible PL enhancing responses to the electron injection effect increasing the radiative recombination, while PL quenching was attributed to be due to the electron extraction effect increasing the nonradiative recombination. The control of PL by external applied voltage indicates brilliant carrier mobility in the CHNHPbI crystal and also reminds us to focus on the effect of hole/electron injection on the materials which may limit the performance of perovskite-based optoelectronic devices.
在过去十年中，有机金属卤化物钙钛矿（OMHPs）已成为适用于光电器件的材料。然而，人们观察到OMHPs在外部电场下存在各种复杂的缓慢响应，这些响应的机制仍是激烈争论的话题。在这项工作中，在CHNHPbI晶体上施加外部电压时，在宽场荧光显微镜下观察到阳极和阴极附近分别出现可逆的光致发光（PL）增强和猝灭行为。进一步的实验将可逆的PL增强响应归因于电子注入效应增加了辐射复合，而PL猝灭则归因于电子提取效应增加了非辐射复合。通过外部施加电压对PL进行控制，表明CHNHPbI晶体中具有出色的载流子迁移率，这也提醒我们要关注空穴/电子注入对可能限制基于钙钛矿的光电器件性能的材料的影响。
