Halide-Substituted Electronic Properties of Organometal Halide Perovskite Films: Direct and Inverse Photoemission Studies

Chi Li, Jian Wei, Mikio Sato, Harunobu Koike, Zhong Zhi Xie, Yan Qing Li, Kaname Kanai, Satoshi Kera, Nobuo Ueno, Jian Xin Tang

Research output: Contribution to journalArticleResearchpeer-review

112 Citations (Scopus)

Abstract

Solution-processed perovskite solar cells are attracting increasing interest due to their potential in next-generation hybrid photovoltaic devices. Despite the morphological control over the perovskite films, quantitative information on electronic structures and interface energetics is of paramount importance to the optimal photovoltaic performance. Here, direct and inverse photoemission spectroscopies are used to determine the electronic structures and chemical compositions of various methylammonium lead halide perovskite films (MAPbX3, X = Cl, Br, and I), revealing the strong influence of halide substitution on the electronic properties of perovskite films. Precise control over halide compositions in MAPbX3 films causes the manipulation of the electronic properties, with a qualitatively blue shift along the I → Br → Cl series and showing the increase in ionization potentials from 5.96 to 7.04 eV and the change of transport band gaps in the range from 1.70 to 3.09 eV. The resulting light absorption of MAPbX3 films can cover the entire visible region from 420 to 800 nm. The results presented here provide a quantitative guide for the analysis of perovskite-based solar cell performance and the selection of optimal carrier-extraction materials for photogenerated electrons and holes.

Original languageEnglish
Pages (from-to)11526-11531
Number of pages6
JournalACS Applied Materials & Interfaces
Volume8
Issue number18
DOIs
Publication statusPublished - 11 May 2016
Externally publishedYes

Keywords

  • band gap
  • electronic structures
  • inverse photoemission spectroscopy
  • perovskite
  • photoemission spectroscopy

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