Enhanced Charge Transport in 2D Perovskites via Fluorination of Organic Cation

Kai Zhu, Fei Zhang, Haipeng Lu, Bryon Larson, Liguo Gao, Chuanxiao Xiao, Obadiah Reid, Xihan Chen, Qian Zhao, Paul Ndione, Joseph Berry, Matthew Beard, Ji-Sang Park, Wei You, Aron Walsh, Jun Hu, Donghoe Kim, Donghoe Kim

Research output: Contribution to journalArticlepeer-review

280 Scopus Citations

Abstract

Organic-inorganic halide perovskites incorporating two-dimensional (2D) structures have shown promise for enhancing the stability of perovskite solar cells (PSCs). However, the bulky spacer cations often limit charge transport. Here, we report on a simple approach based on molecular design of the organic spacer to improve the transport properties of 2D perovskites, and we use phenethylammonium (PEA) as an example. We demonstrate that by fluorine substitution on the para position in PEA to form 4-fluorophenethylammonium (F-PEA), the average phenyl ring centroid-centroid distances in the organic layer become shorter with better aligned stacking of perovskite sheets. The impact is enhanced orbital interactions and charge transport across adjacent inorganic layers as well as increased carrier lifetime and reduced trap density. Using a simple perovskite deposition at room temperature without using any additives, we obtained a power conversion efficiency of >13% for (F-PEA)2MA4Pb5I16-based PSCs. In addition, the thermal stability of 2D PSCs based on F-PEA is significantly enhanced compared to those based on PEA.

Original languageAmerican English
Pages (from-to)5972-5979
Number of pages8
JournalJournal of the American Chemical Society
Volume141
Issue number14
DOIs
StatePublished - 10 Apr 2019

Bibliographical note

Publisher Copyright:
Copyright © 2019 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-73083

Keywords

  • 2D structures
  • perovskite solar cells
  • perovskites
  • transport properties

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