Effect of Cr and Zr doping of TiO2 on the opto-electrical properties of dye sensitized solar cells

Abstract In this research, we report on the effect of doping TiO2 with chromium and zirconium on the opto-electrical parameters of dye sensitized solar cells (DSSCs). TiO2 films were elaborated by sol-gel and spin-coating routes. Levels of doping agents are 1%, 3% and 5% of atomic ratio. X-Ray diffraction patterns show that when TiO2 is doped with Zr, the sole anatase phase with a preferential orientation along (101) is present. However, doping with Cr leads to the formation of both rutile and anatase phases. Measurements of the transmission spectra show a high transparency for all samples. The band gap energy Eg evaluated from ellipsometric measurements decreases with increasing Cr content and remained approximately unchanged with increasing Zr content. Transmission electron microscopy analysis shows a polycrystalline films. By comparing AM1.5 current density-voltage characteristics of fabricated DSSCs with pure and Cr and Zr doped TiO2 films, results show that the best cell performances are obtained with the 1% Cr-doping level. Therefore, we obtain high values of the open circuit voltage reaching 1350 mV and a 70% fill factor.