Influence of Particle Size of TiO2 Powder on the Energy Conversion Efficiency of a Dye-Sensitized Solar Cell

Dye-sensitized solar cells (DSSCs) have been fabricated using a TiO2 paste composed of mixtures of 25 nm and 250 nm TiO2 particles at various ratios. A maximum energy conversion efficiency of 6.7% has been achieved using the DSSC, based on a TiO2 layer composed of 40 wt% 25 nm and 60 wt% 250 nm TiO2 particles. The short-circuit current density, open-circuit voltage, and filling factor of the cell were 12.95 mA, 0.82 V, and 0.63, respectively. The overall performance of the DSSCs based on TiO2 layers composed using a mixture of two different sized particles is much better than that of either only 25 nm or only 250 nm TiO2 particles. It is recognized that adding the larger particles to the small particles in the TiO2 paste increases the dye absorption and light scattering effects of DSSC, resulting in a higher short-circuit current density and improved energy conversion efficiency.