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Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

The electronic structure of molecules on metal surfaces is largely determined by hybridization and screening by the substrate electrons. As a result, the energy levels are significantly broadened and molecular properties, such as vibrations are hidden within the spectral line shapes. Insertion of th...

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Autores principales: Yousofnejad, Asieh, Reecht, Gaël, Krane, Nils, Lotze, Christian, Franke, Katharina J
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Beilstein-Institut 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385352/
https://www.ncbi.nlm.nih.gov/pubmed/32766091
http://dx.doi.org/10.3762/bjnano.11.91
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author Yousofnejad, Asieh
Reecht, Gaël
Krane, Nils
Lotze, Christian
Franke, Katharina J
author_facet Yousofnejad, Asieh
Reecht, Gaël
Krane, Nils
Lotze, Christian
Franke, Katharina J
author_sort Yousofnejad, Asieh
collection PubMed
description The electronic structure of molecules on metal surfaces is largely determined by hybridization and screening by the substrate electrons. As a result, the energy levels are significantly broadened and molecular properties, such as vibrations are hidden within the spectral line shapes. Insertion of thin decoupling layers reduces the line widths and may give access to the resolution of electronic and vibronic states of an almost isolated molecule. Here, we use scanning tunneling microscopy and spectroscopy to show that a single layer of MoS(2) on Ag(111) exhibits a semiconducting bandgap, which may prevent molecular states from strong interactions with the metal substrate. We show that the lowest unoccupied molecular orbital (LUMO) of tetracyanoquinodimethane (TCNQ) molecules is significantly narrower than on the bare substrate and that it is accompanied by a characteristic satellite structure. Employing simple calculations within the Franck–Condon model, we reveal their vibronic origin and identify the modes with strong electron–phonon coupling.
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spelling pubmed-73853522020-08-05 Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ Yousofnejad, Asieh Reecht, Gaël Krane, Nils Lotze, Christian Franke, Katharina J Beilstein J Nanotechnol Full Research Paper The electronic structure of molecules on metal surfaces is largely determined by hybridization and screening by the substrate electrons. As a result, the energy levels are significantly broadened and molecular properties, such as vibrations are hidden within the spectral line shapes. Insertion of thin decoupling layers reduces the line widths and may give access to the resolution of electronic and vibronic states of an almost isolated molecule. Here, we use scanning tunneling microscopy and spectroscopy to show that a single layer of MoS(2) on Ag(111) exhibits a semiconducting bandgap, which may prevent molecular states from strong interactions with the metal substrate. We show that the lowest unoccupied molecular orbital (LUMO) of tetracyanoquinodimethane (TCNQ) molecules is significantly narrower than on the bare substrate and that it is accompanied by a characteristic satellite structure. Employing simple calculations within the Franck–Condon model, we reveal their vibronic origin and identify the modes with strong electron–phonon coupling. Beilstein-Institut 2020-07-20 /pmc/articles/PMC7385352/ /pubmed/32766091 http://dx.doi.org/10.3762/bjnano.11.91 Text en Copyright © 2020, Yousofnejad et al. https://creativecommons.org/licenses/by/4.0https://www.beilstein-journals.org/bjnano/termsThis is an Open Access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requires that the authors and source are credited. The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: (https://www.beilstein-journals.org/bjnano/terms)
spellingShingle Full Research Paper
Yousofnejad, Asieh
Reecht, Gaël
Krane, Nils
Lotze, Christian
Franke, Katharina J
Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ
title Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ
title_full Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ
title_fullStr Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ
title_full_unstemmed Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ
title_short Monolayers of MoS(2) on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ
title_sort monolayers of mos(2) on ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of tcnq
topic Full Research Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7385352/
https://www.ncbi.nlm.nih.gov/pubmed/32766091
http://dx.doi.org/10.3762/bjnano.11.91
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