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Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers

[Image: see text] It is becoming accepted that ultrathin dielectric layers on metals are not merely passive decoupling layers, but can actively influence orbital energy level alignment and charge transfer at interfaces. As such, they can be important in applications ranging from catalysis to organic...

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Autores principales: Hollerer, Michael, Lüftner, Daniel, Hurdax, Philipp, Ules, Thomas, Soubatch, Serguei, Tautz, Frank Stefan, Koller, Georg, Puschnig, Peter, Sterrer, Martin, Ramsey, Michael G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2017
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492217/
https://www.ncbi.nlm.nih.gov/pubmed/28541656
http://dx.doi.org/10.1021/acsnano.7b02449
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author Hollerer, Michael
Lüftner, Daniel
Hurdax, Philipp
Ules, Thomas
Soubatch, Serguei
Tautz, Frank Stefan
Koller, Georg
Puschnig, Peter
Sterrer, Martin
Ramsey, Michael G.
author_facet Hollerer, Michael
Lüftner, Daniel
Hurdax, Philipp
Ules, Thomas
Soubatch, Serguei
Tautz, Frank Stefan
Koller, Georg
Puschnig, Peter
Sterrer, Martin
Ramsey, Michael G.
author_sort Hollerer, Michael
collection PubMed
description [Image: see text] It is becoming accepted that ultrathin dielectric layers on metals are not merely passive decoupling layers, but can actively influence orbital energy level alignment and charge transfer at interfaces. As such, they can be important in applications ranging from catalysis to organic electronics. However, the details at the molecular level are still under debate. In this study, we present a comprehensive analysis of the phenomenon of charge transfer promoted by a dielectric interlayer with a comparative study of pentacene adsorbed on Ag(001) with and without an ultrathin MgO interlayer. Using scanning tunneling microscopy and photoemission tomography supported by density functional theory, we are able to identify the orbitals involved and quantify the degree of charge transfer in both cases. Fractional charge transfer occurs for pentacene adsorbed on Ag(001), while the presence of the ultrathin MgO interlayer promotes integer charge transfer with the lowest unoccupied molecular orbital transforming into a singly occupied and singly unoccupied state separated by a large gap around the Fermi energy. Our experimental approach allows a direct access to the individual factors governing the energy level alignment and charge-transfer processes for molecular adsorbates on inorganic substrates.
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spelling pubmed-54922172017-07-03 Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers Hollerer, Michael Lüftner, Daniel Hurdax, Philipp Ules, Thomas Soubatch, Serguei Tautz, Frank Stefan Koller, Georg Puschnig, Peter Sterrer, Martin Ramsey, Michael G. ACS Nano [Image: see text] It is becoming accepted that ultrathin dielectric layers on metals are not merely passive decoupling layers, but can actively influence orbital energy level alignment and charge transfer at interfaces. As such, they can be important in applications ranging from catalysis to organic electronics. However, the details at the molecular level are still under debate. In this study, we present a comprehensive analysis of the phenomenon of charge transfer promoted by a dielectric interlayer with a comparative study of pentacene adsorbed on Ag(001) with and without an ultrathin MgO interlayer. Using scanning tunneling microscopy and photoemission tomography supported by density functional theory, we are able to identify the orbitals involved and quantify the degree of charge transfer in both cases. Fractional charge transfer occurs for pentacene adsorbed on Ag(001), while the presence of the ultrathin MgO interlayer promotes integer charge transfer with the lowest unoccupied molecular orbital transforming into a singly occupied and singly unoccupied state separated by a large gap around the Fermi energy. Our experimental approach allows a direct access to the individual factors governing the energy level alignment and charge-transfer processes for molecular adsorbates on inorganic substrates. American Chemical Society 2017-05-25 2017-06-27 /pmc/articles/PMC5492217/ /pubmed/28541656 http://dx.doi.org/10.1021/acsnano.7b02449 Text en Copyright © 2017 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
spellingShingle Hollerer, Michael
Lüftner, Daniel
Hurdax, Philipp
Ules, Thomas
Soubatch, Serguei
Tautz, Frank Stefan
Koller, Georg
Puschnig, Peter
Sterrer, Martin
Ramsey, Michael G.
Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers
title Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers
title_full Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers
title_fullStr Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers
title_full_unstemmed Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers
title_short Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers
title_sort charge transfer and orbital level alignment at inorganic/organic interfaces: the role of dielectric interlayers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492217/
https://www.ncbi.nlm.nih.gov/pubmed/28541656
http://dx.doi.org/10.1021/acsnano.7b02449
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