Chemically Deposited Cd<sub>1-x</sub>Pb<sub>x</sub>Se Thin Films for Photoelectrochemical Studies

Abstract

Optimum composition of Cd1xPbxSe thin films (0.1 x 0.9) were deposited using single precursor bath containing cadmium sulfate octahydrate, lead nitrate, tartaric acid, potassium hydroxide, ammonia and sodium selenosulfate onto fluorinedoped tin oxide (FTO) glass substrates. The photoelectrochemical (PEC) cells were fabricated using Cd1xPbxSe as an active photoelectrode with sulphide/polysulphide redox couple as an electrolyte and sensitized graphite rod as a counter electrode. The various characteristics of the cells namely currentvoltage (IV), capacitancevoltage (CV) in dark, power output, builtinpotential, photoresponse, spectral response measurements were investigated. The cell performance parameters such as opencircuit voltage (Voc), shortcircuit current (Isc), series resistance (Rs), shunt resistance (Rsh), conversion efficiency (η), fill factor (FF), junction ideality factor (nd), builtinpotential (ΦB), flatband potential (Vfb) were evaluated. PEC characteristics reveal ntype semiconducting nature for Cd1xPbxSe thin films with lead composition x < 0.5, while ptype nature for remaining Cd1xPbxSe thin films. Among the various cells, the maximum PEC efficiency (η = 1.401 %) was found to Cd0.7Pb0.3Se thin films; due to its increase in opencircuit voltage (225 mV) as well as shortcircuit current (3.983 mA/cm2),decrease in resistance (Rs= 0.75 kΩ and Rsh= 331 Ω), and increase in photoelectrode absorption as compared to other thin film materials.