1. Modulation of electronic and optical properties of g-CN/XTe2(X=W, Mo) heterojunctions by biaxial strain.
- Author
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Shen, Yang, Yuan, Pei, Yuan, Zhihao, Cui, Zhen, Ma, Deming, Cheng, Fengjiao, Qin, Ke, Wang, Hanxiao, and Li, Enling
- Subjects
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GIBBS' energy diagram , *GIBBS' free energy , *HYDROGEN evolution reactions , *OXYGEN evolution reactions , *DENSITY functional theory - Abstract
The electronic and optical properties under biaxial strains, as well as the Gibbs free energy profiles for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of the g-C 3 N 4 /WTe 2 and g-C 3 N 4 /MoTe 2 (g-CN/XTe 2 , X = W, Mo) heterojunctions were studied by first-principles based on density functional theory (DFT). The g-CN/WTe 2 and g-CN/MoTe 2 heterojunctions exhibit type-II band alignment, and are direct bandgap semiconducting with bandgap of 1.272 eV and 1.481 eV, respectively. Compared to intrinsic g-CN, the g-CN/XTe 2 heterojunctions show enhanced light absorption in the ultraviolet and visible regions. The power conversion efficiency (PCE) of the g-CN/WTe 2 and the g-CN/MoTe 2 heterojunctions are 17.89 % and 22.37 %, respectively. Under the biaxial strain, the bandgap, band alignment, light absorption properties and PCE of the g-CN/XTe 2 (X = W, Mo) heterojunctions can be modulated. Especially, the PCE of the g-CN/WTe 2 heterojunction increases up to 22.52 % under 2 % biaxial strain. In addition, under 4H coverage, the over-potentials of HER in g-CN/WTe 2 and g-CN/MoTe 2 are 1.149 V and 1.148 V, and the over-potentials of OER are 2.341 V and 2.438 V, respectively. These results indicate that g-CN/XTe 2 heterojunctions hold promise for applications in solar cell devices and electrocatalytic hydrogen production. • The PCE of the g-CN/MoTe 2 heterojunction reach 22.37 %. • For the g-CN/WTe 2 heterojunction, the PCE increases form 17.89 %–22.52 % at 2 % strain. • Under biaxial strains, absorption spectra of g-CN/XTe 2 heterojunctions are redshifted. • The g-CN/XTe 2 heterojunctions achieve low over-potentials of HER under 4 H coverage. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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