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Title: Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces

Abstract

Electronic level alignment at interfaces of molecular materials with inorganic semiconductors and metals controls many interfacial phenomena. How the intrinsic properties of the interacting systems define the electronic structure of their interface remains one of the most important problems in molecular electronics and nanotechnology that can be solved through a combination of surface science experimental techniques and theoretical modeling. In this article, we address this fundamental problem through experimental and computational studies of molecular electronic level alignment of thin films of C6F6 on noble metal surfaces. The unoccupied electronic structure of C6F6 is characterized with single molecule resolution using low-temperature scanning tunneling microscopy-based constant-current distance-voltage spectroscopy. The experiments are performed on several noble metal surfaces with different work functions and distinct surface-normal projected band structures. In parallel, the electronic structures of the quantum wells (QWs) formed by the lowest unoccupied molecular orbital state of the C6F6 monolayer and multilayer films and their alignment with respect to the vacuum level of the metallic substrates are calculated by solving the Schrödinger equation for a semiempirical one-dimensional (1D) potential of the combined system using input from density functional theory. Our analysis shows that the level alignment for C6F6 molecules bound through weak vanmore » der Waals interactions to noble metal surfaces is primarily defined by the image potential of metal, the electron affinity of the molecule, and the molecule surface distance. We expect the same factors to determine the interfacial electronic structure for a broad range of molecule/metal interfaces.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1222138
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
ACS Nano, 8(10):10988–10997
Additional Journal Information:
Journal Name: ACS Nano, 8(10):10988–10997
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Zhao, Jin, Feng, Min, Dougherty, Daniel B., Sun, Hao, and Petek, Hrvoje. Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces. United States: N. p., 2014. Web. doi:10.1021/nn5049969.
Zhao, Jin, Feng, Min, Dougherty, Daniel B., Sun, Hao, & Petek, Hrvoje. Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces. United States. https://doi.org/10.1021/nn5049969
Zhao, Jin, Feng, Min, Dougherty, Daniel B., Sun, Hao, and Petek, Hrvoje. 2014. "Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces". United States. https://doi.org/10.1021/nn5049969.
@article{osti_1222138,
title = {Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces},
author = {Zhao, Jin and Feng, Min and Dougherty, Daniel B. and Sun, Hao and Petek, Hrvoje},
abstractNote = {Electronic level alignment at interfaces of molecular materials with inorganic semiconductors and metals controls many interfacial phenomena. How the intrinsic properties of the interacting systems define the electronic structure of their interface remains one of the most important problems in molecular electronics and nanotechnology that can be solved through a combination of surface science experimental techniques and theoretical modeling. In this article, we address this fundamental problem through experimental and computational studies of molecular electronic level alignment of thin films of C6F6 on noble metal surfaces. The unoccupied electronic structure of C6F6 is characterized with single molecule resolution using low-temperature scanning tunneling microscopy-based constant-current distance-voltage spectroscopy. The experiments are performed on several noble metal surfaces with different work functions and distinct surface-normal projected band structures. In parallel, the electronic structures of the quantum wells (QWs) formed by the lowest unoccupied molecular orbital state of the C6F6 monolayer and multilayer films and their alignment with respect to the vacuum level of the metallic substrates are calculated by solving the Schrödinger equation for a semiempirical one-dimensional (1D) potential of the combined system using input from density functional theory. Our analysis shows that the level alignment for C6F6 molecules bound through weak van der Waals interactions to noble metal surfaces is primarily defined by the image potential of metal, the electron affinity of the molecule, and the molecule surface distance. We expect the same factors to determine the interfacial electronic structure for a broad range of molecule/metal interfaces.},
doi = {10.1021/nn5049969},
url = {https://www.osti.gov/biblio/1222138}, journal = {ACS Nano, 8(10):10988–10997},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 28 00:00:00 EDT 2014},
month = {Tue Oct 28 00:00:00 EDT 2014}
}