Structure engineering of hierarchical layered perovskite interface for efficient and stable wide bandgap photovoltaics

Tongle Bu, Jing Li, Qingdong Lin, David P. McMeekin, Jingsong Sun, Mingchao Wang, Weijian Chen, Xiaoming Wen, Wenxin Mao, Christopher R. McNeill, Wenchao Huang, Xiao Li Zhang, Jie Zhong, Yi Bing Cheng, Udo Bach, Fuzhi Huang

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Wide bandgap perovskite solar cells (PSCs) are a key component for the realization of highly efficient tandem solar cells. To simultaneously improve the efficiency and stability is still a big challenge. Herein, phenylmethylamine bromide (PMABr) is employed to modify FA0.8Cs0.2Pb(I0.7Br0.3)3 wide bandgap perovskite films. This large cation is incorporated via a post-treatment, which induces a hierarchical layered perovskite and passivates the halide vacancies with the added Br. The morphology of post-treated films is investigated with synchrotron-based techniques, revealing the formation of a layered structure at the surface, which depends upon the concentration of the PMABr solution. In particular a hierarchical microstructure is observed, consisting of a highly stable pure 2D (n = 1) perovskite layer on top of an efficient quasi-2D (n = 2) perovskite layer that caps an underlying 3D perovskite film. By precisely controlling the surface structure and thickness of the 2D perovskites, wide bandgap (~1.74 eV) PSCs reach an efficiency of 18.5% with negligible hysteresis and a stabilized efficiency of 17.9%. Furthermore, the device moisture stability is also significantly enhanced after the post-treatment, indicating that the post-treatment with PMABr is a viable processing method to achieve both efficient and stable wide bandgap PSCs.

Original languageEnglish
Article number104917
Number of pages7
JournalNano Energy
Volume75
DOIs
Publication statusPublished - Sep 2020

Keywords

  • Interface
  • Layered perovskite
  • Morphology
  • Stability
  • Wide bandgap perovskite solar cells

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