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Title: Temperature dependent energy levels of methylammonium lead iodide perovskite

Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.
Authors:
; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)
  2. Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)
  3. Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)
  4. Chemistry Department and Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164 (United States)
Publication Date:
OSTI Identifier:
22483077
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DENSITY FUNCTIONAL METHOD; ENERGY LEVELS; LEAD IODIDES; MEV RANGE 100-1000; MEV RANGE 10-100; PERFORMANCE; PEROVSKITE; PHOTOELECTRON SPECTROSCOPY; SOLAR CELLS; TEMPERATURE DEPENDENCE; THERMAL EXPANSION; ULTRAVIOLET RADIATION