The Journal of Physical Chemistry C, 130, 3, 1363–1369 (2026)
In Situ Observation of Surface Decomposition and Recrystallization of Post Synthesis Metal Halide Perovskite Thin Films
Wanxin Zhang1,2, Haitao Dai2, Zhixin Hu1,2 and Zhixiang Sun1,2
1 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300072, China.
2 Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300072, China.
* zsun@tju.edu.cn
Abstract
We present an in situ atomic force microscopy (AFM) study of surface dynamics in solution-processed MAPbI₃ thin films under ambient conditions. Time-resolved AFM imaging reveals location-dependent decomposition in certain exposed regions alongside simultaneous recrystallization in adjacent areas, with crystal growth primarily occurring via edges from surface screw dislocations or pre-existing ones. These dynamic processes are significantly suppressed on the surface of MA0.4FA0.6PbI₃ films. We propose a surface decomposition-diffusion-integration mechanism to explain these phenomena. The decomposition products (PbI₂ and MAI) can stay and diffuse across surface steps and combine at low-energy edges, as supported by first-principles calculations. Our work provides direct experimental evidence for rich surface dynamics in the post synthesis MAPbI₃ and MA0.4FA0.6PbI₃ thin films under ambient conditions and reveals decomposition and surface recrystallization as key processes affecting film surface properties. These findings offer new insights into the metal halide perovskite film growth, surface stability, and microscopic degradation mechanisms.
