The effect of light-scattering layer on the performance of dye-sensitized solar cell assembled using TiO_2 double-layered films as photoanodes

摘要

Dye-sensitized solar cells (DSSCs) are fabricated based on double-layered films of TiO_2 nanospheres and TiO_2 nanorod arrays (NRAs). TiO_2 nanospheres, including TiO_2 hollow spheres (HSs) and TiO_2 solid spheres (SSs), were served as light-scattering layers on TiO_2 NRAs as composite photoanodes. The as-prepared TiO_2 NRAs, TiO_2 HSs and TiO_2 SSs have been characterized by field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The photoelectric properties of DSSCs were investigated by UV-vis reflectance spectra, current-voltage curves and electrochemical impedance spectroscopy. Owing to the synergic effects of the TiO_2 HSs (SSs) and NRAs, including large specific surface area of HSs (SSs) as light-scattering layer for effective dye adsorption and harvesting light and rapid electron transport in one dimensional TiO_2 NRAs, the optimal energy conversion efficiency of DSSCs with as-prepared double-layered films as nano-composite photoanode (5.40%) were far higher than the ones using single-layered NRAs films (1.56%).