Predicting single-layer technetium dichalcogenides (TcX2, X = S, Se) with promising applications in photovoltaics and photocatalysis

Jiao, Yalong and Zhou, Liujiang and Ma, Fengxian and Gao, Guoping and Kou, Liangzhi and Bell, John and Sanvito, Stefano and Du, Aijun (2016) Predicting single-layer technetium dichalcogenides (TcX2, X = S, Se) with promising applications in photovoltaics and photocatalysis. ACS Applied Materials and Interfaces, 8 (8). pp. 5385-5392. ISSN 1944-8244


Abstract

One of the least known compounds among transition metal dichalcogenides (TMDCs) is the layered triclinic technetium dichalcogenides (TcX2, X = S, Se). In this work, we systematically study the structural, mechanical, electronic, and optical properties of TcS2 and TcSe2 monolayers based on density functional theory (DFT). We find that TcS2 and TcSe2 can be easily exfoliated in a monolayer form because their formation and cleavage energy are analogous to those of other experimentally realized TMDCs monolayer. By using a hybrid DFT functional, the TcS2 and TcSe2 monolayers are calculated to be indirect semiconductors with band gaps of 1.91 and 1.69 eV, respectively. However, bilayer TcS2 exhibits direct-bandgap character, and both TcS2 and TcSe2 monolayers can be tuned from semiconductor to metal under effective tensile/compressive strains. Calculations of visible light absorption indicate that 2D TcS2 and TcSe2 generally possess better capability of harvesting sunlight compared to single-layer MoS2 and ReSe2, implying their potential as excellent light-absorbers. Most interestingly, we have discovered that the TcSe2 monolayer is an excellent photocatalyst for splitting water into hydrogen due to the perfect fit of band edge positions with respect to the water reduction and oxidation potentials. Our predictions expand the two-dimensional (2D) family of TMDCs, and the remarkable electronic/optical properties of monolayer TcS2 and TcSe2 will place them among the most promising 2D TMDCs for renewable energy application in the future.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Research and Innovation Division (12 Jul 2012 -)
Faculty/School / Institute/Centre: Current - Research and Innovation Division (12 Jul 2012 -)
Date Deposited: 11 Sep 2020 02:19
Last Modified: 30 Sep 2020 01:35
Uncontrolled Keywords: two-dimensional materials; technetium dichalcogenides; photovoltaics; photocatalysis; strain effect
Fields of Research (2008): 09 Engineering > 0904 Chemical Engineering > 090499 Chemical Engineering not elsewhere classified
Fields of Research (2020): 40 ENGINEERING > 4004 Chemical engineering > 400499 Chemical engineering not elsewhere classified
Identification Number or DOI: https://doi.org/10.1021/acsami.5b12606
URI: http://eprints.usq.edu.au/id/eprint/39369

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