engleski

Study of the growth process of nitrosobenzene adlayers on gold surface

Adsorption of organic molecules on solid surfaces followed by their arrangements into ordered self- assembled monolayers (SAMs) and/or multilayers offers a way for design of functional materials with potential applications in areas such as catalysis, sensing, medicine, molecular electronics, etc. Surface properties of SAMs can be finely tuned by incorporation of different terminal functionalities which can be used to link specific molecules or nanostructures. It is well- known that aromatic C-nitroso compounds can exist as monomers, and Z- and E-azodioxides. Our recent studies indicated that dimerization of aromatic C- nitroso derivatives to azodioxides is also possible at metal-solution interface resulting with formation of self-assembled bilayers (SABs). Here, we wish to gain new insights into the on- surface assembling dynamics of nitrosobenzenes by studying the influence of solution concentration and adsorption time on formation of monolayers and bilayers on an Au(111). For this purpose, two nitrosobenzene derivatives with alkyl chains of different lengths (propyl and hexyl) ending with thiocyanate headgroup for adsorption on gold were synthesized. The growth of monolayers and bilayers of nitrosobenzene derivatives on an Au(111) surface was studied at different solution concentrations and adsorption times by using ellipsometry, atomic force microscopy (AFM) and scanning tunneling microscopy (STM). The obtained results suggest formation of more ordered adlayers and increased tendency towards bilayers at higher solution concentration and longer adsorption times.

nitrosobenzene ; azodioxides ; self-assembled monolayers ; self-assembled bilayers

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