Abstract Organic-inorganic hybrid perovskite solar cells have shown great prospect as a low-cost and high efficiency photovoltaic technology. The large grain and excellent surface morphology is most critical to obtain high performance perovskite solar cell. Here, a post-treatment method using Cesium iodide (CsI) solution is developed to improve the crystallization and morphology of the perovskite films. The solvent dissolves the small perovskite grains and the Cesium promote the large grain growth, which results in the increase in grain size from 270 nm to 650 nm and decrease in root-mean-square roughness from 15.8 nm to 8.6 nm. The decrease of defect states in the CsI treated methyl-ammonium lead iodide film is confirmed by the photoluminescence. Finally, the efficiency of the perovskite solar cells treated by 6 mg/ml CsI reached to 15.3%, which is 45.7% higher than that of the untreated device (10.5%).

中文翻译：

---

碘化铯后处理制备大晶粒光滑铯掺杂 CH3NH3PbI3 钙钛矿薄膜，用于改进太阳能电池

摘要 有机-无机杂化钙钛矿太阳能电池作为一种低成本、高效率的光伏技术显示出广阔的前景。大晶粒和优异的表面形貌是获得高性能钙钛矿太阳能电池的关键。在这里，开发了一种使用碘化铯 (CsI) 溶液的后处理方法，以改善钙钛矿薄膜的结晶和形态。溶剂溶解小钙钛矿晶粒，铯促进大晶粒生长，导致晶粒尺寸从 270 nm 增加到 650 nm，均方根粗糙度从 15.8 nm 降低到 8.6 nm。光致发光证实了 CsI 处理的甲基铵碘化铅薄膜中缺陷态的减少。最后，钙钛矿太阳能电池经 6 mg/ml CsI 处理后的效率达到 15.3%，