Nebulizer spray-deposited CuInGaS2 thin films, a viable candidate for counter electrode in dye-sensitized solar cells

Abstract

Abstract Nebulizer spray pyrolysis technique has been employed to deposit the CuInGaS2 (CIGS) counter electrode at different substrate temperatures. The XRD patterns revealed that the obtained films are in tetragonal structure with the preferential orientation of (1 1 2) plane and crystalline parameters were calculated. The A1 mode of CIGS film was observed at 296 cm−1 by Raman spectra, which is a combination of CH- and CA-orderings. Uniform spherical growth of grains with the least surface roughness was observed for CIGS film deposited at 350° C. The chemical states and composition of the deposited films were analyzed by XPS. The electrical parameters and Arrhenius plot of CIGS thin films were studied. The electrochemical studies of CIGS counter electrodes by different techniques such as cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization suggested the high electro-catalytic activity of the material towards I−/I3− redox electrolyte for dye-sensitized solar cell (DSSC) application. The performance of DSSC devices fabricated using different CIGS counter electrodes were evaluated from current density–voltage (J-V) measurements. The maximum short-circuit current density (Jsc) and photon to current conversion efficiency (η) of 12.32 mA/cm2 and 4.32% were obtained for the counter electrode prepared at 350 °C.