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He G, Lu L, Zhang N, Liu W, Chen Z, Li Z, Zou Z. Narrowing the band gap and suppressing electron-hole recombination in β-Fe 2O 3 by chlorine doping. Phys Chem Chem Phys 2023; 25:3695-3701. [PMID: 36651804 DOI: 10.1039/d2cp04723c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The effects of halogen (F, Cl, Br, I, and At) doping in the direct-band-gap β-Fe2O3 semiconductor on its band structures and electron-hole recombination have been investigated by density functional theory. Doping Br, I, and At in β-Fe2O3 leads to transformation from a direct-band-gap semiconductor to an indirect-band-gap semiconductor because their atomic radii are too large; however, F- and Cl-doped β-Fe2O3 remain as direct-band-gap semiconductors. Due to the deep impurity states of the F dopant, this study focuses on the effects of the Cl dopant on the band structures of β-Fe2O3. Two impurity levels are introduced when Cl is doped into β-Fe2O3, which narrows the band gap by approximately 0.3 eV. After doping Cl, the light-absorption edge of β-Fe2O3 redshifts from 650 to 776 nm, indicating that its theoretical solar to hydrogen efficiency for solar water splitting increases from 20.6% to 31.4%. In addition, the effective mass of the holes in halogen-doped β-Fe2O3 becomes significantly larger than that in undoped β-Fe2O3, which may suppress electron-hole recombination.
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Affiliation(s)
- Gaoxiang He
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China.
| | - Linguo Lu
- Department of Physics, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA.
| | - Ningsi Zhang
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China.
| | - Wangxi Liu
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China.
| | - Zhongfang Chen
- Department of Physics, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, USA.
| | - Zhaosheng Li
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China.
| | - Zhigang Zou
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093, People's Republic of China.
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