Effect of porosity on the efficiency of DSSC produced by using nano-size TiO2 powders

Abstract

The effect of porosity on the energy conversion efficiency of dye-sensitized solar cells (DSSCs) prepared by using pastes formed by mixing 20 nm and 200 nm TiO2 particles in different ratios is investigated. XRD and SEM analysis have been done to investigate the microstructure of pastes. The energy conversion efficiency of DSSCs was determined by drawing complete current density-voltage curve. The DSSC prepared using the mixture composed of 40 wt% 20 nm and 60 wt% 200 nm TiO2 particles maintained best energy conversion efficiency of 6.74%. The energy conversion efficiency of the DSSCs prepared by using pastes based on the mixture of two different size of TiO 2 particles is much better than that of the DSSCs prepared by using pastes composed of either only 20 nm or only 200 nm of TiO2 particles. The improved energy conversion efficiency is attributed to the establishment of further porous structure that lets more dye absorption from the surface through interior which provides enhancement of light absorption and multiple scattering.