Cation Diffusion Guides Hybrid Halide Perovskite Crystallization during the Gel Stage. Issue 15 (11th February 2020)

• Record Type: Journal Article
• Authors: Liu, Lang; Bai, Yang; Zhang, Xiao; Shang, Yuequn; Wang, Chenyue; Wang, Hao; Zhu, Cheng; Hu, Chen; Wu, Jiafeng; Zhou, Huanping; Li, Yujing; Yang, Shihe; Ning, Zhijun; Chen, Qi
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 15(2020)
• Page Start: 5979
• Page End: 5987
• Publication Date: 2020-02-11
• Subjects: diffusion -- gels -- perovskites -- phase segregation; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201914183
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Lead halide perovskites with mixed cations/anions often suffer from phase segregation, which is detrimental to device efficiency and their long‐term stability. During perovskite film growth, the gel stage (in between liquid and crystalline) correlates to phase segregation, which has been rarely explored. Herein, cation diffusion kinetics are systematically investigated at the gel stage to develop a diffusion model obeying Fick's second law. Taking 2D layered perovskite as an example, theoretical and experimental results reveal the impact of diffusion coefficient, temperature, and gel duration on the film growth and phase formation. A homogenous 2D perovskite thin film was then fabricated without significant phase segregation. This in‐depth understanding of gel stage and relevant cation diffusion kinetics would further guide the design and processing of halide perovskites with mixed composition to meet requirements for optoelectronic applications. Abstract : Mixed lead halide perovskites often suffer from phase segregation. This phenomenon correlates to the cation diffusion kinetics at the gel stage. Now, a homogenous 2D perovskite thin film was successfully fabricated without significant phase segregation. This understanding should guide the design and processing of halide perovskites to meet the requirements for optoelectronic applications.