(496b) Optoelectronic Properties of Graphene-Noble Metal Thin Films for Energy Storage and Conversion Applications

Carbon nanomaterials and noble metal nanoparticles constitute an ideal miniaturized composite platform for integration with emerging electronic technologies. Applications of graphene thin films into solid-state electrodes for energy storage and conversion are few in the multitude hypothesized areas of material incumbent technological replacements. The abundance of carbon factors well with low cost for raw materials and potential for scalability for wide-spread application. Graphene thin films that are layer-by-layer assembled using various noble metal nanoparticles (such as Pt, Pd, Au, Ru, and Ni) have optoelectronic properties high transmissivity and high conductance similar to that of industrial adopted transparent conducting oxides (TCOs) that have a lower relative abundance. In addition to being physically ductile, nanocomposite thin films comprised of graphene and choice of noble metal nanoparticle for functionalization may tune the band energies to alter charge transport and recombination through the layered 3D thin film structure. Graphene thin films possess higher conductivity as a low-weight and high surface area thin film compared to that of a pure metal which is advantageous in fabricating electrodes for batteries ranging from children’s household electronics to the warfighter on the battlefield. Characterization of the layer-by-layer spin cast deposition process is monitored with scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) spectroscopy and thin film profilometry to quality control the fabrication of films. Transmissivity, reflectance, and absorptivity (TRA) measurements using a UV/VIS spectrophotometer with integrating sphere assists us in understanding the bulk material properties such as band energy of the films as a function of metal nanoparticle and film thickness. Optical performance of graphene noble metal films creating a p-n junction are characterized with an AM 1.5G solar simulator to access photoconductivity and resistance and external quantum efficiency measurements assess the responsivity of the thin films as a function of the photon excitation wavelength.