Ordered RTiO2@ATiO2 architecture for dye-sensitized solar cell applications

Abstract

Herein, we report a green and convenient method to prepare a compact layer for better construction of hierarchical TiO₂ architectures to serve as photoanodes, in which one-dimensional (1D) rutile TiO₂ (R_TiO2) arrays are grown hydrothermally on a compact layer for fast electron transport, and branched anatase TiO₂ (A_TiO2) particles are deposited orderly on R_TiO2 backbones for high efficiency dye harvesting. Characteristic tests indicate that the 1D R_TiO2 arrays are tetragonal in shape with a square top surface, whereas the branched A_TiO2 particles are nanoconic in shape with exposed {001} facets. As a result, the R_TiO2@A_TiO2 photoanode, sensitized by the N719 dye, harvests a solar energy conversion efficiency of 5.68%, which is nearly 3 times higher than that found in the R_TiO2 array-based dye-sensitized solar cell (DSSC), which demonstrates that the R_TiO2 nanorods decorated by A_TiO2 nanocones are helpful in enhancing the solar energy conversion efficiency.