Study on Crystallization Kinetics and Photovoltaic Performance of Perovskite Films with Embedding of PbS Nanocrystals in Grains

Author of the article:LIU Chen1 , ZHAI Jizhou2 , GUO Pengfei1,3, WANG Hongqiang1,3

Author's Workplace：1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 2. Xi'an Institute for Innovative Earth Environment Research, Xi'an 710061, China; 3. Innovation Center NPU Chongqing, Chongqing 401135, China

Key Words：heterointerfaces in grains; crystallization kinetics; environmental stability; power conversion efficiency; hybrid perovskite films; PbS nanocrystals

Abstract：Organic and inorganic hybrid perovskite solar cells have achieved rapid development in power conversion efficiency but remain formidable challenges in environmental stability, owing to the intrinsic instability of perovskite ions that can induce low crystal quality during rapid crystallization. The present work innovatively proposed a regulation strategy for constructing heterointerfaces in grains to improve the crystallization kinetics and environmental stability of perovskite films. Such a heterointerface was constructed by controllable embedding of laser-prepared ligand-free PbS nanocrystals in perovskite grains. As a result, the embedding of PbS nanocrystals can inhibit the formation of the intermediate phase, accelerate the nucleation rate and slow the growth rate of perovskite crystals, consequently contributing to the improved crystal quality and environmental stability of perovskite films. Benefiting from these merits, perovskite solar cells based on the embedding of PbS nanocrystals have achieved a power conversion efficiency up to 22.12% . Moreover, the unencapsulated devices maintain over 95% of their initial values after 5 000 h under a relative humidity of 40% and deliver a thermal stability of 1 000 h even under thermal stress of 85 ℃.