Investigation of electrical values of low-efficiency dye-sensitized solar cells (DSSCs)

Abstract

Indium-tin-oxide (ITO)/density (d)- titanium dioxide (TiO2)/nonporous (nonp)-TiO2 is a TiO2-based bilayer photoanode. These photoanodes coated for dye-sensitized solar cells (DSSCs) were with nonp-TiO2 surface and had very thick ITO layer. DSSCs were fabricated with these photoanodes. After their current density-voltage (J-V) were analyzed, ıt was seen that they were low efficiency and the shape of their J-V curve was linear line instead of rectangle. In this study, it was examined the relationship between the dark current (IDC), the series resistance (Rs) and the shunt resistance (Rsh) were examined for evaluating the fill factor (FF) of low-efficiency DSSCs because of the photoanodes with nonp-TiO2 surfaces and very thick ITO for contact layer. It was seen in the J-V graph of DSSCs which had low FF value due to their IDC and low Rsh. The J-V graph of low-efficiency DSSCs is linear due to their low Rsh and high Rs values. Moreover, the too thick ITO layer decreases the resistance of photoanodes; however, electrons in these photoanodes can not efficiently transferred to external circuit from ITO contact layer of DSSCs.