Photovoltaic studies of hybrid metal oxide semiconductors as photo anode in dye sensitized solar cells

Abstract

Dye sensitized solar cells (DSSCs) have fascinated researchers across the globe since their inception in 1991, due to their easy preparation protocols compared to the conventional silicon solar cells and eco-friendly nature. Most of the time best choice of metal oxide semiconductor is TiO2 because of its high electron injection rate. But on the other hand, wide band gap semiconductor such as ZnO has higher stability and electron mobility. We anticipated that combination of these two should help us to get the better devices. In this study, working electrode modification was done by using hybrid metal oxides as in the fabrication of DSSC to increase the efficiency of the device. ZnO nanoparticles were synthesized by sol-gel process. The morphology, porosity and grain size of the ZnO was studied by SEM analysis. The Particle size was further confirmed by XRD analysis. Bulk and nano TiO2 were blended individually with nano ZnO and their photo voltaic parameters were examined. Used combinations were (i) TiO2-n (ii) TiO2-b (iii) ZnO-n (iv) TiO2-n: TiO2-b in 1:1 ratio (v) ZnO-n: TiO2-n in 1:1 ratio (vi) ZnO-n:TiO2-b in 1:1 ratio respectively along with N719 dye. After assembling the electrodes, the current density-voltage characteristics of each of the combinations were evaluated. It was found that among all the combinations TiO2nano and bulk composition in the proportion 1:1 is showing the optimum efficiency than the other compositions.