Improving the Responsivity of Hybrid Graphene–Conductive Polymer Photodetectors via Nanowire Self-Assembly

Abstract

By changing the morphology of a poly(3-hexylthiophene) (P3HT) conductive polymer via self-assembly from a planar thin film to a nanowire mesh mesostructure, we demonstrate hybrid graphene–conductive polymer photodetectors with an experimentally observed 600% improved photoresponsivity when compared to their analogous hybrid photodetectors based on graphene and a planar P3HT thin film of similar thickness. At least two reasons stand behind such a dramatic increase in photoresponsivity: (i) the polymer nanowire mesh architecture with unit cell dimensions comparable to the wavelength of light, which produces light scattering and increased light absorption in the polymer compared to the case of a planar polymer thin film of similar thickness, and (ii) the crystallization of P3HT molecules within the nanowires reduces the density of charge trap states, which in turn provides improved charge transport and charge transfer compared to a P3HT thin film.