Optical and electrochemical properties of spinel cubic nanostructured thin film Co3O4 prepared by spray pyrolysis

Abstract

In this present, a spinel cubic Co3O4 nanostructured thin film has been deposited by a simple and inexpensive spray pyrolysis method on preheated FTO substrate at different temperatures of the substrate (TS = 350 ̊C, 400 ̊C, 450 ̊C, and 500 ̊C). The surface, optical and structural properties of these films have been studied by FESEM, UV–Vis, and XRD analyses. According to these results the film has been deposited at TS = 400 ̊C chooses for electrochemical tests. The surface morphology investigated by FESEM and structural properties has been studied by XRD patterns. The grain size of samples was calculated by XRD patterns and FESEM images. The average grain size was about 30 nm, and the results of XRD and FESEM confirmed each other. UV–vis spectroscopy of these films shows that they have two absorption edges with direct and indirect bandgap at 2.2 and 1.5 eV, respectively. The electrochemical properties of this electrode have been analyzed by CV, impedance, and charge/discharge curve. The CV curve was investigated at different scan rates: 100, 80, 60, 40, 20, and 10 mv.s-1. The specific capacitance of the above electrode was decreased by increasing the scan rate. The specific capacitance of this electrode was calculated by CV and charge/discharge curve and it was 1800 F/g. The electrochemical analysis shows that the capacity of this electrode decreases only 4% after 5000 cycles therefore it is a very stable electrode.