Solvent volume dependent physical properties and electrocatalytic ability of nebulizer spray deposited CuInGaS2 counter electrode for dye-sensitized solar cells

Abstract

CuInGaS2 (CIGS) thin films were coated using nebulizer spray technique for different solvent volumes (10, 30, 50 and 70 ml) at the substrate temperature of 350 °C. The structural, optical and electrical properties were studied for the prepared CIGS thin films. CIGS thin films exhibited tetragonal structure and the maximum crystallite size was calculated for the film deposited using 50 ml solvent volume. The surface morphology of CIGS thin films was analyzed from scanning electron microscopy and atomic force microscopy studies. The electrical parameters of CIGS thin films such as resistivity, carrier concentration and mobility were examined using four probe method and Hall measurements. Electrocatalytic activities of the CIGS films towards redox couple (I−/I3−) were analyzed by cyclic voltammograms, electrochemical impedance spectroscopy, and Tafel polarization measurements. The high photocurrent efficiency was obtained for the CIGS counter electrode prepared using 50 ml solvent volume.