Nanostructured graphene-platinum-PEDOT electrode materials for enhanced Schottky performance and power conversion applications

Abstract

Counter electrode are crucial components in determining the efficiency of dye-sensitized solar cells. An ideal electrode material would have high conductivity (i.e. high electron mobility) and excellent catalytic activity for electrolyte reduction. Various electrode materials have been investigated, however most materials demonstrate either the catalytic activity or the conductivity. In this paper, we investigated combining the catalytic and electrical conductivity for enhanced electrode materials by fabricating of a hybrid structure consisting of PEDOT/graphene/Pt/semiconductor heterojunction. A hybrid structure was successfully fabricated by atomic layer deposition of Pt over the surface of n-silicon followed by plasma-enhanced chemical vapor deposition of graphene sheets and then an immediate spin coating of PEDOT prepared by solution casting polymerization. The hybridstructure showed a noticeable difference in the reflection/absorption measurements where the absorption drastically increased upon PEDOT deposition. The photoluminescence emission spectra showed two main peaks at 525 nm and 700 nm, with an enhancement in the band-to-band PL process attributed to the separation of the photo-generated charges and the excitonic PL signal related to surface defects and states. Moreover, the electrical characterization of the hybrid electrodes showed a response of about 7.15 × 10−6 A, which is nearly 7 times that of the bare graphene, as well as electrical stability for a period of 300 s under dark conditions.