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

Fei Zhang, Dong Hoe Kim, Haipeng Lu, Ji Sang Park, Bryon W. Larson, Jun Hu, Liguo Gao, Chuanxiao Xiao, Obadiah G. Reid, Xihan Chen, Qian Zhao, Paul F. Ndione, Joseph J. Berry, Wei You, Aron Walsh, Matthew C. Beard, Kai Zhu

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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 languageEnglish
Pages (from-to)5972-5979
Number of pages8
JournalJournal of the American Chemical Society
Volume141
Issue number14
DOIs
Publication statusPublished - 2019 Apr 10

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Zhang, F., Kim, D. H., Lu, H., Park, J. S., Larson, B. W., Hu, J., Gao, L., Xiao, C., Reid, O. G., Chen, X., Zhao, Q., Ndione, P. F., Berry, J. J., You, W., Walsh, A., Beard, M. C., & Zhu, K. (2019). Enhanced Charge Transport in 2D Perovskites via Fluorination of Organic Cation. Journal of the American Chemical Society, 141(14), 5972-5979. https://doi.org/10.1021/jacs.9b00972