Dependence of energy conversion efficiency of dye-sensitized solar cells on the annealing temperature of TiO2 nanoparticles

Dye-sensitized solar cells (DSSCs) were fabricated from porous electrodes derived from sol–gel-synthesized (SGS) nanoparticles (NPs) of TiO2. Current–voltage measurements were performed to investigate performance characteristics of electrodes derived from SGS-NPs of TiO2 annealed at different temperatures. Experimental results indicate that the effects of bulk traps and surface states within TiO2 films on recombination of photo-injected electrons in DSSCs depend upon annealing temperature of SGS-TiO2 NPs. Moreover, electrodes fabricated from SGS-TiO2 showed higher photoelectric conversion efficiency than nonporous commercial (P25) TiO2 NPs. Porous structures within SGS-TiO2 NPs are of great benefit to sensitizer dye adsorption, and consequently to improvement of photo-electrochemical properties of DSSCs.