Direct observation of adsorption geometry for the van der Waals adsorption of a single π-conjugated hydrocarbon molecule on Au(111)

Journal Article · Fri Feb 21 04:00:00 EST 2014 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4864458· OSTI ID:22255100

Kim, Ju-Hyung ^[1]; Jung, Jaehoon; Kim, Yousoo ^[2]; Tahara, Kazukuni; Tobe, Yoshito ^[3]; Kawai, Maki ^[1]

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1. Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)
2. Surface and Interface Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
3. Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

Weak van der Waals adsorption of π-conjugated hydrocarbon molecules onto the gold surface, Au(111), is one of the essential processes in constructing organic-metal interfaces in organic electronics. Here we provide a first direct observation of adsorption geometry of a single π-conjugated hydrocarbon molecule on Au(111) using an atomically resolved scanning tunneling microscopy study combined with van der Waals density functional methodology. For the purpose, we utilized a highly symmetric π-conjugated hydrocarbon molecule, dehydrobenzo[12]annulene (DBA), which has a definite three-fold symmetry, the same as the Au(111) surface. Interestingly, our observations on an atomically resolved scale clearly indicate that the DBA molecule has only one adsorption configuration on Au(111) in spite of the weak van der Waals adsorption system. Based on the precisely determined adsorption geometry of DBA/Au(111), our calculation results imply that even a very small contribution of the interfacial orbital interaction at the organic-metal interface can play a decisive role in constraining the adsorption geometry even in the van der Waals adsorption system of a π-conjugated hydrocarbon molecule on the noblest Au(111) surface. Our observations provide not only deeper insight into the weak adsorption process, but also new perspectives to organic electronics using π-conjugated hydrocarbon molecules on the Au surface.

• OSTI ID: 22255100
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 7 Vol. 140; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ADSORPTION
CRYSTAL LATTICES
GOLD
HYDROCARBONS
INTERACTIONS
MOLECULES
SCANNING TUNNELING MICROSCOPY
SURFACES
VAN DER WAALS FORCES