Intragrain impurity annihilation for highly efficient and stable perovskite solar cells

Songhua Cai; Zhipeng Li; Yalan Zhang; Tanghao Liu; Peng Wang; Ming-Gang Ju; Shuping Pang; Shu Ping Lau; Xiao Cheng Zeng; Yuanyuan Zhou

doi:10.1038/s41467-024-46588-y

Intragrain impurity annihilation for highly efficient and stable perovskite solar cells

Nat Commun. 2024 Mar 14;15(1):2329. doi: 10.1038/s41467-024-46588-y.

Authors

Songhua Cai^#¹, Zhipeng Li^#², Yalan Zhang³, Tanghao Liu⁴, Peng Wang⁵, Ming-Gang Ju⁶, Shuping Pang⁷, Shu Ping Lau⁸, Xiao Cheng Zeng⁹, Yuanyuan Zhou¹⁰

Affiliations

¹ Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China. songhua.cai@polyu.edu.hk.
² Qingdao Institute of Bioenergy & Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China.
³ Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China.
⁴ Department of Physics, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.
⁵ Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
⁶ Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China. juming@seu.edu.cn.
⁷ Qingdao Institute of Bioenergy & Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China. pangsp@qibebt.ac.cn.
⁸ Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
⁹ Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, China.
¹⁰ Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China. yyzhou@ust.hk.

^# Contributed equally.

Abstract

Intragrain impurities can impart detrimental effects on the efficiency and stability of perovskite solar cells, but they are indiscernible to conventional characterizations and thus remain unexplored. Using in situ scanning transmission electron microscopy, we reveal that intragrain impurity nano-clusters inherited from either the solution synthesis or post-synthesis storage can revert to perovskites upon irradiation stimuli, leading to the counterintuitive amendment of crystalline grains. In conjunction with computational modelling, we atomically resolve crystallographic transformation modes for the annihilation of intragrain impurity nano-clusters and probe their impacts on optoelectronic properties. Such critical fundamental findings are translated for the device advancement. Adopting a scanning laser stimulus proven to heal intragrain impurity nano-clusters, we simultaneously boost the efficiency and stability of formamidinium-cesium perovskite solar cells, by virtual of improved optoelectronic properties and relaxed intra-crystal strain, respectively. This device engineering, inspired and guided by atomic-scale in situ microscopic imaging, presents a new prototype for solar cell advancement.