High Efficiency (16.37%) of Cesium Bromide-Passivated All-Inorganic CsPbI2Br Perovskite Solar Cells
High Efficiency (16.37%) of Cesium Bromide-Passivated All-Inorganic CsPbI2Br Perovskite Solar Cells
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高%20效率%20(16.37%)%20%20铯%20溴化物钝化%20全无机%20CsPbI2Br%20钙钛矿%20太阳能%20电池
DOI：
10.1002/solr.201900254
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发表时间：
2019
期刊：
影响因子：
7.9
通讯作者：
Qu Bo
中科院分区：
文献类型：
--
作者：
Zhang Yuqing;Wu cuncun;Wang Duo;Zhang Zehao;Qi Xin;Zhu Ning;Liu Ganghong;Li Xiangdong;Hu Haozhe;Chen Zhijian;Xiao Lixin;Qu Bo
全无机CsPbI2Br钙钛矿由于其出色的热稳定性和适合光电器件的带隙而越来越受到人们的关注。然而，由于钙钛矿薄膜的低质量和高陷阱密度导致CsPbI2Br钙钛矿太阳能电池（PSCs）的功率转换效率（PCE）不合格和能量损失（Eloss）大，仍然限制了器件的应用。本文利用蒸发溴化铯（CsBr）在钙钛矿表面进行后处理，钝化cspbi2br -空穴-输运层界面，降低损耗。微区光致发光结果表明，蒸发的CsBr聚集在CsPbI2Br层的晶界处，形成富Br钙钛矿（CsPbIxBr3−x,x< 2），对CsPbI2Br具有保护作用。因此，填补了晶粒之间的间隙，从而降低了全无机CsPbI2Br psc的复合损失。冠军器件具有高开路电压，PCE分别为1.271 V和16.37%。这是迄今为止报道的所有无机CsPbI2Br PSCs中最高的PCE。此外，CsBr钝化有效提高了CsPbI2Br PSCs的稳定性，未封装的器件在贮存1368 h后可保留初始PCE的86%，有利于实际应用。
All‐inorganic CsPbI2Br perovskite has attracted increasing attention, owing to its outstanding thermal stability and suitable bandgap for optoelectronic devices. However, the substandard power conversion efficiency (PCE) and large energy loss (Eloss) of CsPbI2Br perovskite solar cells (PSCs) caused by the low quality and high trap density of perovskite films still limit the application of devices. Herein, the post‐treatment of evaporating cesium bromide (CsBr) is utilized on top of the perovskite surface to passivate the CsPbI2Br–hole‐transporting layer interface and reduceEloss. The results of microzone photoluminescence indicate that the evaporated CsBr gathered at the grain boundaries of CsPbI2Br layers and Br‐enriched perovskites (CsPbIxBr3−x,x< 2) are formed, which can provide protection for CsPbI2Br. Therefore, the gaps between crystal grains are filled up, and the recombination loss of the all‐inorganic CsPbI2Br PSCs is reduced accordingly. The champion device exhibits high open‐circuit voltage and a PCE of 1.271 V and 16.37%, respectively. This is the highest reported PCE among all‐inorganic CsPbI2Br PSCs reported so far. In addition, the stability of CsPbI2Br PSCs is effectively improved by CsBr passivation, and the device without encapsulation can retain 86% of its initial PCE after 1368 h of storage, which is beneficial for practical applications.