High-efficiency solid-state dye-sensitized solar cells based on TiO(2)-coated ZnO nanowire arrays.

Replacing the liquid electrolytes in dye-sensitized solar cells (DSCs) with solid-state hole-transporting materials (HTMs) may solve the packaging challenge and improve the long-term stability of DSCs. The efficiencies of such solid-state DSCs (ss-DSCs), however, have been far below the efficiencies of their counterparts that use liquid electrolytes, primarily due to the challenges in filling HTMs into thick enough sensitized films based on sintered TiO(2) nanoparticles. Here we report fabrication of high-efficiency ss-DSCs using multilayer TiO(2)-coated ZnO nanowire arrays as the photoanodes. The straight channel between the vertically aligned nanostructures combined with a newly developed multistep HTM filling process allows us to effectively fill sensitized films as thick as 50 μm with the HTMs. The resulting ss-DSCs yield an average power conversion efficiency of 5.65%.