Functionalized nanocomposites of gold and their optical studies

Post-functionalization strategy on gold nanoparticles (Au NPs) surface provides access to novel nanocomposite materials with specific physico-chemical properties for a variety of interdisciplinary applications. In this work, functionalized gold nanocomposites (Au NCs) with unique morphological features were achieved by utilizing Ruthenium(II)-polypyridyl complexes with various functional groups. They were synthesized by using ethanol/water medium at room temperature by place-exchange methodology. As the progress of binding Ru(II)-polypyridyl complex molecules, changed from ionic to covalent fashion, then Ru(II)-polypyridyl complex molecules-induced self-assembly was observed. This was evident in UV-Vis spectroscopic and TEM studies. Additionally, Ru(II)-polypyridyl complexes binding showed altered Au NPs surface with SERS enhancement at micromolar concentration level and Raman scattering signals of Au surface-bound Ru(II)-polypyridyl complexes were studied through a hot spot mechanism.