Imaging the Moisture-Induced Degradation Process of 2D Organolead Halide Perovskites

Jianbo Tang; Wenming Tian; Chunyi Zhao; Qi Sun; Chunyang Zhang; Hui Cheng; Yantao Shi; Shengye Jin

doi:10.1021/acsomega.1c06989

Imaging the Moisture-Induced Degradation Process of 2D Organolead Halide Perovskites

ACS Omega. 2022 Mar 16;7(12):10365-10371. doi: 10.1021/acsomega.1c06989. eCollection 2022 Mar 29.

Authors

Jianbo Tang^{1

2}, Wenming Tian^{1

3}, Chunyi Zhao⁴, Qi Sun⁵, Chunyang Zhang⁶, Hui Cheng^{1

7}, Yantao Shi⁶, Shengye Jin¹

Affiliations

¹ State Key Laboratory of Molecular Reaction Dynamics and the Dynamic Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.
³ Key Laboratory of Excited-State Materials of Zhejiang Province, Zhejiang University, Hangzhou 310027, China.
⁴ Anhui Province Key Laboratory of Optoelectronic Material Science and Technology, School of Physics and Electronic Information, Anhui Normal University, Wuhu 241002, China.
⁵ MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics & Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
⁶ State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
⁷ Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, School of Microelectronics, Dalian University of Technology, Dalian 116024, China.

Abstract

Two-dimensional (2D) and quasi-2D Ruddlesden-Popper (RP) phase organolead halide perovskites are promising materials for both photovoltaic and optoelectronic devices. Although they are known to be more stable when exposed to moisture than their 3D counterpart, chemical degradation of these materials under moisture, which not only leads to a significant drop in device performance but also leads to lead leakage, yet remains one of the most serious hurdles for their practical applications. To gain insight into the degradation mechanism of 2D/quasi-2D perovskites under moisture conditions, the degradation pathway of 2D/quasi-2D (PEA)₂(MA) _n-1Pb_nI_3n+1 (PEA = C₆H₅C₂H₄NH₃ ⁺, MA = CH₃NH₃ ⁺, and n is the number of perovskite layers between adjacent organic spacer layers) perovskite single crystals (SCs) and thin film are explored. We observe the degradation process by mapping the photoluminescence of the 2D perovskites and demonstrate that the larger-n phases all directly degrade into the relative stable n = 1 phase and MAI and PbI₂, which is a mechanism different from that in previous reports and further confirmed in the 2D perovskite thin film. This degradation process is also found to be independent of the boundary and morphology of the SCs. This discovery provides a new perspective for understanding the chemical degradation of the 2D perovskite materials and may inspire new solutions for improving their moisture stability.