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Title: Top and bottom surfaces limit carrier lifetime in lead iodide perovskite films

Carrier recombination at defects is detrimental to the performance of solar energy conversion systems, including solar cells and photoelectrochemical devices. Point defects are localized within the bulk crystal while extended defects occur at surfaces and grain boundaries. If not properly managed, surfaces can be a large source of carrier recombination. Separating surface carrier dynamics from bulk and/or grain-boundary recombination in thin films is challenging. Here, we employ transient reflection spectroscopy to measure the surface carrier dynamics in methylammonium lead iodide perovskite polycrystalline films. We find that surface recombination limits the total carrier lifetime in perovskite polycrystalline thin films, meaning that recombination inside grains and/or at grain boundaries is less important than top and bottom surface recombination. As a result, the surface recombination velocity in polycrystalline films is nearly an order of magnitude smaller than that in single crystals, possibly due to unintended surface passivation of the films during synthesis.
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States); New Jersey Institute of Technology, Newark, NJ (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2058-7546
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nature Energy
Additional Journal Information:
Journal Volume: 2; Journal Issue: 2; Journal ID: ISSN 2058-7546
Nature Publishing Group
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S); USDOE NREL Director's Fellowship; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; surface recombination; perovskite solar cells; transient spectroscopy; solar cells; solar energy; optical spectroscopy
OSTI Identifier: