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

March 18, 2019 

Through fluorine substitution on the para position in phenethylammonium (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.

Scientific Achievement

We enhanced out-of-plane transport in 2D perovskites via simple molecular modification of the organic spacer. Specifically, fluorine substitution on the para position in PEA to form F-PEA strengthens inter-plane coupling with faster out-of-plane transport.

Significance and Impact

2D perovskite is promising with good stability, but out-of-plane transport is limited by the bulky organic cation spacer. Our work shows a general molecular engineering approach to tune the electronic coupling between 2D sheets to improve carrier transport.

Research Details

  • Solution processing to prepare 2D perovskite thin films based on PEA
  • Fluorine substitution on the para position in PEA to form F-PE)
  • Detailed spectroscopic and electrical measurements to understand carrier transport and defect properties

DOI: 10.1021/jacs.9b00972

Related People

Joseph J. Berry
National Renewable Energy Laboratory

Wei You
University of North Carolina, Chapel Hill

Matthew Beard
National Renewable Energy Laboratory

Kai Zhu
National Renewable Energy Laboratory

chart of time-resolved microwave conductivity comparison

Time-resolved microwave conductivity comparison of out-of-plane and in-plane charge transport for n = 1 2D perovskite thin films based on (PEA)2PbI4 and (F-PEA)2PbI4. The structures of (PEA)2PbI4 and (F-PEA)2PbI4 are derived from single-crystal X-ray diffraction measurement.