Titania Nanotubes Decorated with Zn‐Doped Titania Nanoparticles as the Photoanode Electrode of Dye‐Sensitized Solar Cells

Abstract

We decorated Zn‐doped TiO2‐nanoparticle‐based photoanodes with carbon nanotube (CNT)‐derived TiO2 nanotubes (TNs) to enhance the power conversion efficiency of dye‐sensitized solar cells (DSCs). X‐ray photoelectron spectroscopy analysis verified that Zn ions, in the range of 0 to 1 at %, were successfully doped into the TiO2 lattice. Field‐emission SEM and TEM images of the TNs, as derived from the sol–gel template‐assisted route, revealed that a uniform TiO2 coating with a thickness of 60 to 120 nm was deposited on the surface of the CNT template through a noncovalent route. We observed that the cell efficiency improved from 6.80 for pure TiO2 to 7.52 for 0.75 at % Zn‐doped TiO2 nanoparticles due to a reduction in charge recombination and enhancement in electron injection, as confirmed by using photoluminescence spectroscopy. Further improvements in the efficiency of up to 8.47 % were achieved by the incorporation of 5 wt % TNs into the Zn‐doped TiO2 photoanodes, as a result of enhancements in electron transport and light scattering, which was verified by using diffuse reflectance spectroscopy.