TY  - JOUR
AU  - Xu, Zhengwei
AU  - Zhao, Yicheng
AU  - Zhang, Jiyun
AU  - Chen, Keqiu
AU  - Brabec, Christoph J.
AU  - Feng, Yexin
TI  - Phase diagram and stability of mixed-cation lead iodide perovskites: A theory and experiment combined study
JO  - Physical review materials
VL  - 4
IS  - 9
SN  - 2475-9953
CY  - College Park, MD
PB  - APS
M1  - FZJ-2021-00755
SP  - 095401
PY  - 2020
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000571166200001
DO  - DOI:10.1103/PhysRevMaterials.4.095401
UR  - https://juser.fz-juelich.de/record/890166
ER  -