Exploration of Crystallization Kinetics in Quasi Two-Dimensional Perovskite and High Performance Solar Cells

• Published in: Journal of the American Chemical Society 2018-01, Vol.140 (1), p.459-465
• Main Authors: Zhou, Ning, Shen, Yiheng, Li, Liang, Tan, Shunquan, Liu, Na, Zheng, Guanhaojie, Chen, Qi, Zhou, Huanping
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.7b11157

Halide perovskites with reduced-dimensionality (e.g., quasi-2D, Q-2D) have promising stability while retaining their high performance as compared to their three-dimensional counterpart. Generally, they are obtained in (A1)2(A2) n−1Pb n I3n+1 thin films by adjusting A site cations, however, the underlying crystallization kinetics mechanism is less explored. In this manuscript, we employed ternary cations halides perovskite (BA)2(MA,FA)3Pb4I13 Q-2D perovskites as an archetypal model, to understand the principles that link the crystal orientation to the carrier behavior in the polycrystalline film. We reveal that appropriate FA+ incorporation can effectively control the perovskite crystallization kinetics, which reduces nonradiative recombination centers to acquire high-quality films with a limited nonorientated phase. We further developed an in situ photoluminescence technique to observe that the Q-2D phase (n = 2, 3, 4) was formed first followed by the generation of n = ∞ perovskite in Q-2D perovskites. These findings substantially benefit the understanding of doping behavior in Q-2D perovskites crystal growth, and ultimately lead to the highest efficiency of 12.81% in (BA)2(MA,FA)3Pb4I13 Q-2D perovskites based photovoltaic devices.