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Title: Orbital controlled band gap engineering of tetragonal BiFeO 3 for optoelectronic applications

Bismuth ferrite BiFeO 3 (BFO) is an important ferroelectric material for thin-film optoelectronic sensing and potential photovoltaic applications. Its relatively large band gap, however, limits the conversion efficiency of BFO absorber-based PV devices. In this study, based on density functional theory calculations we demonstrate that with well-designed Fe-site elemental substitution, tetragonal BFO can exhibit a much lower fundamental band gap than conventional rhombohedral BFO without forming in-gap electronic states and unravel the underlying mechanisms. Cation atomic size, electronegativity, and crystallographic symmetry are evidenced as critical parameters to tailor the metal 3d – oxygen 2p orbital interactions and thus intrinsically modify electronic structure, particularly, the shape and character of the valence and conduction band edges. With reduced band gap, improved mobility, and uncompromised ferroelectric and magnetic ground states, the present results provide a new strategy of designing high symmetry BFO for efficient optoelectronic applications.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [5] ;  [2] ;  [6]
  1. Univ. of Electronic Science and Technology of China, Chengdu (China). School of Physics; Univ. of Manchester (United Kingdom). School of Materials; Univ. of New South Wales, Sydney, NSW (Australia). School of Materials
  2. Univ. of Electronic Science and Technology of China, Chengdu (China). School of Physics
  3. Univ. of Missouri, Columbia, MO (United States). Dept. of Physics and Astronomy
  4. Xiamen Univ., Xiamen (China). College of Chemistry and Chemical Engineering; Univ. of Cambridge (United Kingdom). Dept. of Materials Science and Engineering
  5. Lanzhou City Univ., Lanzhou (China). Dept. of Physics
  6. Univ. of New South Wales, Sydney, NSW (Australia). School of Materials
Publication Date:
Grant/Contract Number:
SC0014607; U1530129; 11774044
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry C
Additional Journal Information:
Journal Volume: 6; Journal Issue: 5; Journal ID: ISSN 2050-7526
Publisher:
Royal Society of Chemistry
Research Org:
Univ. of Missouri, Columbia, MO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 33 ADVANCED PROPULSION SYSTEMS; 36 MATERIALS SCIENCE; Band gap engineering; Optical absorption; BiFeO3; DFT+U
OSTI Identifier:
1419252