Spectroscopic Ellipsometry and Electrochemical and X-ray Photoelectron Spectroscopy Investigation of the Influence of the Crystalline Plane on the Adsorption of α,ω-Alkanedithiols: Mono Versus Bi-Coordinated Configurations

ARISNABARRETA, NICOLÁS; RUANO, GUSTAVO D.; JACQUELÍN, DANIELA K.; PATRITO, E. MARTÍN; COMETTO, FERNANDO P.

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2019 vol. 123 p. 2278 - 2278

1932-7447

he effect of the Au surface crystalline plane on the configuration ofself-assembled monolayers (SAMs) of α,ω-alkanedithiols (DTs) is studied viareductive desorption (RD), X-ray photoelectron spectroscopy (XPS), andspectroscopic ellipsometry (SE) experiments. A remarkable difference in the SAMconfiguration of short DTs, such as 1,4-butanedithiol (C4DT) on both Au(111) andAu(100) is observed; while standing up (SU)-configured SAMs are formed on the(111) plane, lying down molecules form the structure on (100). The higher stability of the bi-coordinated structure on Au(100) is interpreted, indirectly, as higher bonding energies for the RS−Au(100) bond, in agreement with the RD and XPS results.Because hardly no SU phases are detected when adsorbing C4DT on Au(100), alonger DT is needed in order to achieve this configuration, namely, 1,6-hexanedithiol (C6DT). In this case, although the RSC6DT−Au(100) bond is similar to RSC4DT−Au(100) in the bi-coordinated phase,