Electrochemical studies of Langmuir-Blodgett thin films of electroactive nanoparticles

Thin films (monolayers and multilayers) of omega -ferrocenated gold nanoparticles were fabricated by using the Langmuir-Blodgett technique. The transfer of nanoparticle layers onto a solid substrate surface was quite efficient for the first few layers, exhibiting a proportional increase of optical absorption 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 relatively weak interparticle interactions. With depositions of more nanoparticle layers, the particle thin films became less conductive, resulting in the anodic shift of the ferrocene formal potential. Because of the compact characteristics of the nanoparticle thin films, not all ferrocene sites were active and accessible, and the corresponding voltammetric currents varied only slightly with more particle layers.