Thermodynamic understanding of crystal nucleation and growth for halide perovskite films

초록

Optoelectronic properties and phase stability of halide perovskite films are predominantly governed by crystallinity and defect density of thin films. Since the halide perovskite films are generally prepared by solution process, a sufficient engineering window for modulation of nucleation and subsequent growth is ensured, leading to remarkable advances in obtaining high-quality films in line with developing various engineering strategies to control the nucleation and growth processes. This mini-review paper covers crystallization process of halide perovskite film, where basic mechanisms are introduced based on LaMer framework with Classical nucleation theory while deriving adjustable key parameters for crystallization. Meanwhile, effective strategies, being widely adopted for preparing a high-performing perovskite film, are scrutinized to understand their underlying mechanisms from thermodynamic perspective by carefully assessing the respective contribution from a surface term-in close relation with interfacial energy-driven and a volume term-in close relation with supersaturation degree-driven total Gibbs free energy change. Furthermore, subsequent crystal growth kinetics are understood by introducing two extreme conditions of diffusion-controlled and reaction-controlled growth, where underlying mechanisms of effective strategies are examined to correlate their influence on the extreme growth conditions. Lastly, the representative models for particle coarsening are introduced to understand post-growth mechanisms for grain growth.

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