Formation of single-crystalline rutile TiO2 splitting microspheres for dye-sensitized solar cells

The morphological evolution of specimen taken out after the different duration in TiCl₃ solution was investigated by field emission scanning electron microscopy (FE-SEM). The rutile TiO₂ splitting microspheres may be formed by the splitting crystal growth mechanism through the multistep process. The microsphere composed of the 20 nm width nanorods was in the range of 1.5–2.5 μm in the diameter. The dye-sensitized solar cell (DSC) based on the microspheres received 3.57% conversion efficiency under simulated AM 1.5 (100 mW/cm²) solar illumination, which exhibited remarkably higher charge collection efficiency and light scattering compared to that of P25. Electrochemical impedance spectroscopy (EIS) measurement revealed that impedance resistance at the surface of single-crystalline rutile TiO₂ splitting microspheres was 6 times larger than that of P25 nanoparticles, indicating electron recombination was significantly retarded.