Electrochemical studies of Langmuir-Blodgett thin films of electroactive nanoparticles

Thin films (monolayers and multilayers) of omega -ferrocenated gold nanopar ticles were fabricated by using the Langmuir-Blodgett technique. The transf er of nanoparticle layers onto a solid substrate surface was quite efficien t for the first few layers, exhibiting a proportional increase of optical a bsorption in the UV-vis range. The interfacial dynamics of the nanoparticle monolayers was studied by using electrochemical methods where the surface reorganization was ascribed to the particle molecular mobility due to relat ively weak interparticle interactions. With depositions of more nanoparticl e layers, the particle thin films became less conductive, resulting in the anodic shift of the ferrocene formal potential. Because of the compact char acteristics of the nanoparticle thin films, not all ferrocene sites were ac tive and accessible, and the corresponding voltammetric currents varied onl y slightly with more particle layers.