Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2

Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS2 upon adsorption of various gas molecules (H2, O2, H2O, NH3, NO, NO2, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the de...

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Main Authors: Zhou, Changjie, Yang, Weihuang, Zhu, Huili
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2015
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Online Access:https://hdl.handle.net/10356/106046
http://hdl.handle.net/10220/26239
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spelling sg-ntu-dr.10356-1060462023-02-28T19:42:07Z Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2 Zhou, Changjie Yang, Weihuang Zhu, Huili School of Physical and Mathematical Sciences DRNTU::Science::Chemistry::Physical chemistry::Electrochemistry Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS2 upon adsorption of various gas molecules (H2, O2, H2O, NH3, NO, NO2, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS2 with a low degree of charge transfer and accept charge from the monolayer, except for NH3, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS2 are not significantly altered upon adsorption of H2, H2O, NH3, and CO, whereas the lowest unoccupied molecular orbitals of O2, NO, and NO2 are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS2. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS2. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides. Published version 2015-07-03T02:42:05Z 2019-12-06T22:03:36Z 2015-07-03T02:42:05Z 2019-12-06T22:03:36Z 2015 2015 Journal Article Zhou, C., Yang, W., & Zhu, H. (2015). Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2. The journal of chemical physics, 142(21), 214704-. https://hdl.handle.net/10356/106046 http://hdl.handle.net/10220/26239 10.1063/1.4922049 en The journal of chemical physics © 2015 American Institute of Physics (AIP). This paper was published in The Journal of Chemical Physics and is made available as an electronic reprint (preprint) with permission of American Institute of Physics (AIP). The published version is available at: [http://dx.doi.org/10.1063/1.4922049]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. 9 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Chemistry::Physical chemistry::Electrochemistry
spellingShingle DRNTU::Science::Chemistry::Physical chemistry::Electrochemistry
Zhou, Changjie
Yang, Weihuang
Zhu, Huili
Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2
description Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS2 upon adsorption of various gas molecules (H2, O2, H2O, NH3, NO, NO2, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS2 with a low degree of charge transfer and accept charge from the monolayer, except for NH3, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS2 are not significantly altered upon adsorption of H2, H2O, NH3, and CO, whereas the lowest unoccupied molecular orbitals of O2, NO, and NO2 are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS2. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS2. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Zhou, Changjie
Yang, Weihuang
Zhu, Huili
format Article
author Zhou, Changjie
Yang, Weihuang
Zhu, Huili
author_sort Zhou, Changjie
title Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2
title_short Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2
title_full Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2
title_fullStr Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2
title_full_unstemmed Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2
title_sort mechanism of charge transfer and its impacts on fermi-level pinning for gas molecules adsorbed on monolayer ws2
publishDate 2015
url https://hdl.handle.net/10356/106046
http://hdl.handle.net/10220/26239
_version_ 1759857976475123712