%0 Journal Article
%A Xu, Zhengwei
%A Zhao, Yicheng
%A Zhang, Jiyun
%A Chen, Keqiu
%A Brabec, Christoph J.
%A Feng, Yexin
%T Phase diagram and stability of mixed-cation lead iodide perovskites: A theory and experiment combined study
%J Physical review materials
%V 4
%N 9
%@ 2475-9953
%C College Park, MD
%I APS
%M FZJ-2021-00755
%P 095401
%D 2020
%X Alloying structurally similar perovskites to form mixed-cation lead iodide perovskites, e.g., CsxFA(1−x)PbI3, MAxFA(1−x)PbI3, and CsxMAyFA(1−x−y)PbI3, could improve the performance of perovskite-based solar cells and light-emitting diodes. However, a phase diagram of them and a clear understanding of the underlying atomic-scale mechanism are still lacking. Using ab initio calculations combined with high-throughput experimentation, we demonstrate the phase diagram of mixed-cation lead iodide perovskites. Only a small proportion of monovalent cations (Cs+/Rb+/MA+) could be incorporated into the FAPbI3/MAPbI3 matrix; otherwise it will be separated into δ-CsPbI3, δ-RbPbI3, MAI, etc. The smaller the radius of doping cations, the harder it is to incorporate them into a perovskite lattice and the easier it is to stabilize the perovskite phase. In FAPbI3-based multication perovskites, moreover, over 10 mol % alloying is needed to convert δ phase to α phase at room temperature. The combined upper and lower limits for doping concentration restrict the appropriate alloying ratio to a narrow window. We further plot the relative energy diagram for triple-cation perovskite CsxMAyFA(1−x−y)PbI3, which reveals the ideal doping ratio for uniform stable alloying. This theory-experiment-combined study provides a clear microscopic picture of phase stability and segregation for mixed-cation perovskite solids.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000571166200001
%R 10.1103/PhysRevMaterials.4.095401
%U https://juser.fz-juelich.de/record/890166