Design of highly efficient 0D/1D TiO2 photoanode for dye-sensitized solar cells by simple TiCl4 pre-treatment of titanate nanotubes

Abstract

Dye-sensitized solar cells (DSCs) represent a promising avenue for sustainable energy conversion, with the efficiency of these devices heavily reliant on the performance of the TiO2 photoanode. Despite significant advancements, optimizing the photoanode material for higher efficiency remains a challenge. This study introduces a novel approach to constructing a highly efficient, multifunctional 0D/1D TiO2 composite by simply pre-treating the TiO2 precursor, specifically one-dimensional (1D) H-titanate nanotubes, with TiCl4. The TiCl4 treatment not only encourages the extensive synthesis of the one-dimensional nanostructures (i.e., nanorods) but also facilitates the in situ hydrolysis to generate small crystals that attach to the surface of the nanorods. The TiO2 composite offers several essential benefits, including the expanded thickness, high surface area for superior dye adsorption, efficient diffuse light scattering induced by the aggregate structures, and fast charge transport within the film matrix, making it an exemplary component for DSCs. The photovoltaic performance test revealed that TiCl4 pre-treatment increased power conversion efficiency by 36.3 %, rising from 7.63 % of untreated cells to a striking value of 10.4 %, which is a new record when N719 is used as a sensitizer and iodide-based redox shuttle employed as an electrolyte. This research provides an effective strategy for developing highly efficient photoanode material for DSCs.