RESUMEN
The assemblies of cross-linked gold nanoparticles (AuNP) attract lot of scientific attention due to feasible perspectives of their use for development of scaled contact electrodes. Here, we developed and tested method of solid-state formation of dimers created from small AuNP (~18 nm) cross-linked with 1.9-nonadithiol (NDT) molecules. The morphology of created coating of a glass surface and its optical-polarization properties have been studied in detail by combination of scanning electron microscopy, atomic force microscopy, UV-visible spectroscopy, and modulation-polarization spectroscopy.The modification of localized surface plasmon resonance (LSPR) of single AuNP and their assemblies were studied by measuring of the spectral characteristics of polarization difference at all stages of synthesis. The radiative and nonradiative modes of LSPR have been analyzed in detail at different angles of incidence light. This allowed establishing relation between surface morphology of the coating and its optical properties.
RESUMEN
Self-assembled monolayers (SAMs) on Au(111) are able to control the functionality of a gold surface. We use scanning tunnelling microscopy (STM) in air and contact angle measurements to compare the morphology and the chemistry of three alkylthiol SAMs differing by their tail groups: 1,9-nonanedithiol (NDT), 1,4-butanedithiol (BDT) and 11-mercaptoundecanol (MUOH). STM reveals very different morphologies: a hexagonal lattice for MUOH and parallel rows for NDT and BDT. In the case of NDT, we find that the thiol tail groups may form disulfide bridges with long immersion times. The availability of the -SH group for chemical reactions is demonstrated by attaching gold nanoparticles (AuNPs). When the thiol tail group is available, AuNPs readily attach as shown with atomic force microscopy (AFM). When disulfide bridges are formed, the gold surface is not able to bind nanoparticles.