Hollow TiO2 microspheres: template-free synthesis, remarkable structure stability, and improved photoelectric performance

Abstract

Hollow TiO₂ microspheres (HTS) were synthesized via a new one-pot template-free method, which exhibited amazing structure stability even at high temperature calcinations of 800 °C. The formation mechanism study indicates that the growth of HTS is like the inside-out Ostwald ripening process. The resultant HTS possess a fine porous structure and the surface area is high up to 86.5 m² g⁻¹. As a new functional material in the DSSC application, HTS simultaneously offer incompatible features such as a high specific surface area and a pronounced light-scattering effect, and hence an energy conversion efficiency of 6.3% can be archived directly utilizing HTS as photo-anodes. If fabricated into the bilayer structure by introducing HTS as the light scattering layer, the overall conversion efficiency can be further improved to 7.3%. The successful synthesis of these novel photo-anodes opens up a new way to improve the performance of DSSCs.