Anomalous Growth and Coalescence Dynamics of Hybrid Perovskite Nanoparticles Observed by Liquid-Cell Transmission Electron Microscopy

We report on in situ observations of nucleation, growth, and aggregation of hybrid organic-inorganic perovskites by liquid-cell transmission electron microscopy. Direct crystallization of hybrid CH 3 NH 3 PbI 3 nanoparticles is achieved through an electron beam-assisted solvent evaporation approach. Time-lapse liquid-cell TEM imaging of the nanoparticles reveals a growth trend which is not entirely consistent with the classical Lifshitz-Slyozov-Wagner growth model. Significantly complex dynamical behaviors are observed during the coalescence process of CH 3 NH 3 PbI 3 nanoparticles. We propose that the chemical instability inherent in the hybrid perovskite iodides should be considered to understand this phenomenon in addition to the oriented attachment mechanism. This study provides a useful reference for understanding the intriguing chemical and physical properties of hybrid organic-inorganic perovskites.