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Title: Shallow halogen vacancies in halide optoelectronic materials

Halogen vacancies (V H) are usually deep color centers (F centers) in halides and can act as major electron traps or recombination centers. The deep V H contributes to the typically poor carrier transport properties in halides. However, several halides have recently emerged as excellent optoelectronic materials, e.g., CH 3NH 3PbI 3 and TlBr. Both CH 3NH 3PbI 3 and TlBr have been found to have shallow V H, in contrast to commonly seen deep V H in halides. In this paper, several halide optoelectronic materials, i.e., CH 3NH 3PbI 3, CH 3NH 3SnI 3 (photovoltaic materials), TlBr, and CsPbBr 3, (gamma-ray detection materials) are studied to understand the material chemistry and structure that determine whether V H is a shallow or deep defect in a halide material. It is found that crystal structure and chemistry of ns 2 ions both play important roles in creating shallow V H in halides such as CH 3NH 3PbI 3, CH 3NH 3SnI 3, and TlBr. The key to identifying halides with shallow V H is to find the right crystal structures and compounds that suppress cation orbital hybridization at V H, such as those with long cation-cation distances and low anion coordinationmore » numbers, and those with crystal symmetry that prevents strong hybridization of cation dangling bond orbitals at V H. Furthermore, the results of this paper provide insight and guidance to identifying halides with shallow V H as good electronic and optoelectronic materials.« less
Authors:
 [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; HSHQDC-14-R-B0009
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 90; Journal Issue: 17; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Department of Homeland Security (DHS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1185671
Alternate Identifier(s):
OSTI ID: 1180339