Semi-transparent metal nanostructures as alternatives to transparent conducting oxides in organic photovoltaic devices

Semi-transparent metallic, nanostructured, hole-selective contacts are intrinsically more conductive, more chemically stable, easier to modify, and significantly less costly than their transparent conductive oxide (TCO) counterparts traditionally used in organic photovoltaic (OPV) devices. In this work, gold nanowire, nanogrid and honeycomb nanostructures composed of a high work function materials were developed and explored as hole-selective contacts in OPVs. These structures show optical transparency and sheet resistance comparable to those of traditional TCOs that can be easily tuned by varying structure geometry, such as nanowire spacing or nanohole diameter. Results for power conversion efficiency and incident photon current efficiency (IPCE) will be reported for planar heterojunction OPV devices fabricated using these semi-transparent metallic nanostructures as hole-selective contacts and correlated to performance by conventional TCO based architectures.