Synthesis and characterization of Co and Ga co-doped ZnO thin films as an electrode for dye sensitized solar cells

Abstract

Using a time efficient and cost effective approach so called sol‒gel dip coating route, we deposited thin films of ZnO and 1% Co & (0%, 0.5%, 1%, and 1.5%) Ga co-doped ZnO on the fluorine doped tin oxide substrates. All the films exhibited hexagonal wurtzite structure. X-rays study revealed that crystallite size increased with increase of doping. Optical parameters like absorbance, transmittance, refractive index, band gap, extinction coefficient and dielectric constants were measured using UV–Vis spectroscopy and it has been noticed that doping resulted in reduction of band gap. It has also been observed that, the films prepared with 1% Co & 1% Ga co-doped ZnO have comparatively smaller band gap and thus have high refractive index and high transmittance in visible region. The calculation of different electrically important factors for instance, high current density, small open circuit voltage, efficiency and fill factor revealed that co-doped ZnO with 1% Co and 1% Ga has relatively high efficiency of 2.43% and thus shows the potential of this composition as an electrode for solar cell devices.