ZnO / TiO 2 nanonetwork as efficient photoanode in excitonic solar cells

An innovative nanonetwork composed of TiO 2 nanoparticles and single-crystalline ZnO nanowires is demonstrated as efficient photoanode in excitonic solar cells. Such architecture benefits of the capability of high sensitizer loading offered by the nanoparticles and of the direct conduction path for electrons guaranteed by the nanowires. The combination of these features leads to improved light absorption, electron photogeneration, and charge collection. The nanonetwork was implemented in a dye-sensitized solar-cell architecture demonstrating threefold enhancement of the efficiency with respect to a nanowire photoanode of the same thickness. Cell efficiency of 1.6% was obtained in 1.5 μ m thick nanonetwork.