Adsorption States of Dialkyl Ditelluride Autooxidized Monolayers on Au(111)

• Published in: Langmuir Vol. 21; no. 8; pp. 3344 - 3353
• Main Authors: Nakamura, Tohru, Miyamae, Takayuki, Nakai, Ikuyo, Kondoh, Hiroshi, Kawamoto, Tohru, Kobayashi, Nobuhiko, Yasuda, Satoshi, Yoshimura, Daisuke, Ohta, Toshiaki, Nozoye, Hisakazu, Matsumoto, Mutsuyoshi
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.04.2005
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Surface physical chemistry; Monolayer; Atomic force microscopy; Gold; Oxygen; Roughness; Polymer; Transition metal; X ray; Contact angle; Oligomer; Fine structure; Tilt angle; Adsorption; Alkyl; Defect; Photoelectron spectrometry; Oxidation
• DOI: 10.1021/la047620o
• ISSN: 0743-7463

Organic ditellurides (R2Te2 where R = n-butyl (C4), n-octyl (C8), and n-cetyl (C16)) were synthesized, and their adsorption states after oxidation on Au(111) surfaces were studied by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), theoretical analyses, near-edge X-ray absorption fine structure (NEXAFS) measurements, contact angle measurements, and atomic force microscopy (AFM). The obtained results show that dialkyl ditellurides form autooxidized monolayers (AMs) on the surfaces under ambient conditions and that the oxidation process is accelerated by ambient light. XPS, UPS, and theoretical analyses suggest that the autooxidized ditelluride species consist of polymers or oligomers with Te−O−Te−O network structures stabilized by oxygen bridges between tellurium molecules following the cleavage of tellurium−gold bonds. NEXAFS and contact angle measurements indicate that the average tilt angles of the alkyl chains from the surface normal are smaller for the AMs of dialkyl ditellurides having longer alkyl chains. AFM measurements show defects and roughness features around a few angstroms in height on the surfaces of the dialkyl ditelluride AMs.