(103e) High-Efficiency Solid-State Dye-Sensitized Solar Cells Based On TiO2-Coated ZnO Nanowire Arrays

With increasing concern over the twin crises of fossil fuel depletion and environmental degradation, dye-sensitized solar cells (DSCs) have received considerable interest as one of the most promising devices for converting solar energy to electricity at low cost. Replacing the liquid electrolytes in 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 TiO₂nanoparticles. One approach to solving the challenge of filling sensitized films with solid HTMs is to replace the sintered nanoparticle-based mesoporous TiO₂ film with vertically ordered nanostructures. Here we report fabrication of high-efficiency ss-DSCs using multilayer TiO₂-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%.