Scanning tunneling microscopy study on phase behavior of self-assembled monolayers formed by coadsorption of octanethiol and octyl thiocyanate on Au(111)
- Title
- Scanning tunneling microscopy study on phase behavior of self-assembled monolayers formed by coadsorption of octanethiol and octyl thiocyanate on Au(111)
- Author
- 노재근
- Keywords
- Octanethiol; Octyl thiocyanate; Coadsorption; Self-assembled monolayers; Phase behavior; c(4 × 2) phase; Striped phase; Scanning tunneling microscopy
- Issue Date
- 2020-08
- Publisher
- ELSEVIER SCIENCE SA
- Citation
- THIN SOLID FILMS, v. 707, article no. 138100
- Abstract
- To understand headgroup effects on phase behaviors of self-assembled monolayers (SAMs) prepared by coadsorption of octanethiol [OT, CH3(CH2)(7)-SH] and octyl thiocyanate [OTC, CH3(CH2)(7)-SCN] on Au(111) as a function of the OT:OTC molar concentration ratio, we investigated the surface structures of the resulting SAMs formed in 1 mM ethanol solutions at 50 degrees C for 24 h using scanning tunneling microscopy (STM). The STM study showed that the single-component OT SAMs were composed of an ordered c(4 x 2) phase, whereas singlecomponent OTC SAMs had a binary phase consisting of a disordered phase and a striped phase with a distance of 1.3 +/- 0.1 nm between rows. The fully covered c(4x2) phase on Au(111) formed by OT molecules was observed even a molar concentration ratio of OT is equal to OTC (50:50) or is much lower than OTC (10:90). The partially covered striped phase formed by OTC molecules was observed when the molar concentration ratios of OTC were much higher than OT (OT:OTC = 5:95 or OT:OTC = 1:99). Molecular-scale STM results clearly reveal the phase transitions of SAMs on Au(111) via coadsorption of OT and OTC depending on OT:OTC molar ratio. These results will help advance understanding of SAM formation and phase behavior on Au(111) by the coadsorption of alkanethiol and alkyl thiocyanates.
- URI
- https://www.sciencedirect.com/science/article/pii/S0040609020303114?via%3Dihubhttps://repository.hanyang.ac.kr/handle/20.500.11754/170278
- ISSN
- 0040-6090; 1879-2731
- DOI
- 10.1016/j.tsf.2020.138100
- Appears in Collections:
- COLLEGE OF NATURAL SCIENCES[S](자연과학대학) > CHEMISTRY(화학과) > Articles
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