Abstract CsPbBr3 based perovskite solar cells have attracted an increasing attention owing to their high stability in ambient. The conduction band offset (CBO) between electron transportation layer and light absorb layer has important effects on the photovoltaic performance of perovskite solar cells. For the typical device configuration of FTO/TiO2/CsPbBr3/Carbon, the CBO value reaches to ~0.94 eV, which is too high to get efficient electron extraction. It is important to optimize the CBO so as to enhance the photovoltaic performance of the solar cells. In this work, we reduce the CBO value from 0.94 eV to 0.81 eV in the typical device configuration of FTO/TiO2/CsPbBr3/Carbon by using Sr2+ to modify the TiO2 layer. The Sr-modified TiO2 layer facilitates efficient extraction of electrons from CsPbBr3 to electron transportation layer. Meanwhile, the Sr-modified TiO2 layer suppresses the charge recombination rate in the perovskite solar cells. As a result, the power conversion efficiency of solar cells is enhanced from 5.92% to 7.22% by simply introducing a Sr-modified TiO2 layer.

中文翻译：

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通过 Sr 改性的 TiO2 层减少导带偏移来增强 CsPbBr3 钙钛矿太阳能电池的性能

摘要 CsPbBr3基钙钛矿太阳能电池由于其在环境中的高稳定性而受到越来越多的关注。电子传输层和光吸收层之间的导带偏移（CBO）对钙钛矿太阳能电池的光伏性能有重要影响。对于 FTO/TiO2/CsPbBr3/Carbon 的典型器件配置，CBO 值达到 ~0.94 eV，这对于获得有效的电子提取来说太高了。优化CBO以提高太阳能电池的光伏性能非常重要。在这项工作中，我们通过使用 Sr2+ 修饰 TiO2 层，将 FTO/TiO2/CsPbBr3/Carbon 的典型器件配置中的 CBO 值从 0.94 eV 降低到 0.81 eV。Sr 改性的 TiO2 层促进了从 CsPbBr3 到电子传输层的有效电子提取。同时，Sr 修饰的 TiO2 层抑制了钙钛矿太阳能电池中的电荷复合率。因此，通过简单地引入 Sr 改性的 TiO2 层，太阳能电池的功率转换效率从 5.92% 提高到 7.22%。