Spectroscopic Ellipsometry and Electrochemical and X‑rayPhotoelectron Spectroscopy Investigation of the Influence of theCrystalline Plane on the Adsorption ofα,ω-Alkanedithiols: MonoVersus Bi-Coordinated Configurations

E. M. PATRITO

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2019 vol. 123 p. 2278 - 2278

1932-7447

he effect of the Au surface crystalline plane on the configuration of self-assembled monolayers (SAMs) of α,ω-alkanedithiols (DTs) is studied via reductive desorption (RD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE) experiments. A remarkable difference in the SAM configuration of short DTs, such as 1,4-butanedithiol (C4DT) on both Au(111) and Au(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), a longer 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-coordin