Initializing film homogeneity to retard phase segregation for stable perovskite solar cells.
Yang BaiZijian HuangXiao ZhangJiuzhou LuXiuxiu NiuZiwen HeCheng ZhuMengqi XiaoQizhen SongXueyuan WeiChenyue WangZhenhua CuiJing DouYihua ChenFengtao PeiHuachao ZaiWei WangTinglu SongPengfei AnJing ZhangJuncai DongYiming LiJiangjian ShiHaibo JinPengwan ChenYuchao SunYujing LiHaining ChenZhong-Ming WeiHuanping ZhouQi ChenPublished in: Science (New York, N.Y.) (2022)
The mixtures of cations and anions used in hybrid halide perovskites for high-performance solar cells often undergo element and phase segregation, which limits device lifetime. We adapted Schelling's model of segregation to study individual cation migration and found that the initial film inhomogeneity accelerates materials degradation. We fabricated perovskite films (FA<i><sub>1-x</sub></i>Cs<i><sub>x</sub></i>PbI<sub>3</sub>; where FA is formamidinium) through the addition of selenophene, which led to homogeneous cation distribution that retarded cation aggregation during materials processing and device operation. The resultant devices achieved enhanced efficiency and retained >91% of their initial efficiency after 3190 hours at the maximum power point under 1 sun illumination. We also observe prolonged operational lifetime in devices with initially homogeneous FACsPb(Br<sub>0.13</sub>I<sub>0.87</sub>)<sub>3</sub> absorbers.