Light scattering by molecular-organized films on the surface of polycrystalline gold

Abstract

Specific features of the structure of self-assembled layers of dodecanthiol on the surface of polycrystalline films of gold are investigated with the aim of revealing the effect of the substrate relief on the lateral distribution and the predominant orientation of thiol molecules within the limits of the layer. The analysis of the angular dependence of quasi-elastically scattered light that takes into account the contributions of the geometric roughness of the surface and the inhomogeneity of the dielectric constant to scattering allowed us to establish the correlation in antiphase between the distribution of the thickness of the thiol coating and the height of the relief of the gold surface. The formation of a thiol layer on the surface of polycrystalline gold is a complex process including adsorption, local self-assembly, and a surface-induced distortion of the ordered structure in the regions of minima of the surface relief. The approach proposed here and based on the nondestructive analysis of thin organized coatings can be efficiently applied for the study of specific features of the topography and the prediction of chemical functionality of self-assembled molecular ensembles.