Comparative Study on the Influence of TiO₂ Precursors on ZnO-Based Dye-Sensitized Solar Cells

We report the rational surface engineering of ZnO photoanode films by strict control of the TiO₂ precursors for the facile design of hybrid structures and dye-sensitized solar cells (DSSCs) with increased energy conversion efficiencies. The effects of typical Ti sources [i.e., tetrabutyl titanate (TBOT), titanium isopropoxide (TTIP), and titanium tetrachloride (TiCl₄)] on the ZnO film morphology, charge transfer, and DSSC performance were investigated systematically. The testing results revealed that TBOT-treated ZnO film exhibited the highest power conversion efficiency (PCE) and short circuit current density (<i>J</i>_sc) of 4.92% and 12.49 mA/cm², respectively, which were largely improved compared with those of TTIP- and TiCl₄-treated ZnO films under the same conditions. The excellent performance of TBOT-treated ZnO is mainly ascribed to improved light harvesting and increased charge-recombination resistance. Therefore, TBOT can be considered as a promising alternative for constructing TiO₂/ZnO hybrid structures in low-cost ZnO-based DSSCs for outstanding performance