Insight into the Enhanced Charge Transport in Quasi-2D Perovskite via Fluorination of Ammonium Cations for Photovoltaic Applications

Ze Wang, Xiaodong Liu, Hui Ren, Li Liu, Xinyu Tang, Xianghua Yao, Zhenhuang Su, Xingyu Gao, Qi Wei, Haijiao Xie, Yonghao Zheng, Mingjie Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)

Abstract

Fluorinated spacer cations in quasi-2D (Q-2D) perovskites have recently been demonstrated to improve the Q-2D perovskite solar cell (PSC) performance. However, the underlying mechanism of fluorination of organic cations on the improvement is still unclear. Here, using fluorinated benzylammonium (named F-BZA) as a spacer cation in Q-2D Ruddlesden-Popper (RP) perovskites, we deeply investigate the effect of fluorination of organic cations on perovskite crystallization and intermolecular interactions for improving the charge transport and device performance. It is found that fluorination of spacer cations can slow down the crystallization rate of perovskites, resulting in vertically aligned large grains. Moreover, the interaction between the adjacent spacer cations is further enhanced, constructing a new faster charge-transport channel with a lifetime of 77 ps. Accordingly, the carrier mobility is improved by an order of magnitude and a power conversion efficiency (PCE) of 16.82% is achieved in much more stable F-BZA-based Q-2D RP PSCs, 35% higher than that of BZA-based devices (12.39%). Our results elucidate the mechanism and its importance of fluorinating spacer cations for high-performance Q-2D PSC development.

Original languageEnglish
Pages (from-to)7917-7925
Number of pages9
JournalACS Applied Materials and Interfaces
Volume14
Issue number6
DOIs
Publication statusPublished - 16 Feb 2022

Keywords

  • charge transport
  • charge-transfer channel
  • fluorination of ammonium cations
  • quasi-2D perovskite solar cells
  • stability

ASJC Scopus subject areas

  • Materials Science(all)

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