Functional thin film coatings incorporating gold nanoparticles in a transparent conducting fluorine doped tin oxide matrix

Noble nanoparticle-metal oxide composites attract research interest due to their unique combination of properties. We report the successful combination of gold nanoparticles (AuNPs) and F-doped SnO2 composites by layering, producing films that demonstrate unique and interesting optoelectronic properties - high visible transparency, electrical conductivity and with additional plasmonic effects. Both of the layers were deposited by aerosol assisted chemical vapour deposition (AACVD) onto heated glass substrates. Four distinctive sets of films were prepared and analysed consisting of: gold nanoparticles, F-doped SnO2 (FTO), a layer of gold nanoparticles on FTO and an FTO layer on gold nanoparticles. The sizes of the AuNPs were shown to depend on the precursor concentration used. Layered Au:FTO composite films have an attractive blue colouration from the surface plasmon resonance (SPR) of the AuNPs yet have high transparency in the visible region and are electrically conducting, comparable to commercial FTO.