Electrodeposition of Cadmium Selenide Based Photoanodes from TOMAC/Formamide Ionic Liquid System for Photoelectrochemical Water Splitting

Abstract

The electrodeposition from room temperature ionic liquids (RTILs) has recently come up as a low-cost technique for the growth of II–VI semiconductor compounds and thin films, some promising alternatives to classical organic or inorganic solvents. As a relatively new field of study, only a few reports exist describing the growth mechanism of electrodeposition from RTILs, especially for CdSe films. In this paper, a new electrochemical method has been developed for the deposition of Cadmium Selenide thin layers onto indium doped tin oxide coated conducting glass (ITO) using an RTIL and an Organic solvent system (Tricaprylmethylammonium chloride/Formamide). Structural properties of prepared films have been investigated by X-ray diffraction (XRD) and micro-Raman analysis which reveal a pure cubic phase with the zinc-blende-type structure and typical peaks of nanostructured CdSe, respectively. Atomic force microscopy (AFM) analysis showed homogenous and smooth surface of the deposited films. UV-vis measurements demonstrated the presence of direct transition with a band gap energy around 1.68[Formula: see text]eV. The flat-band potential and carrier density values of CdSe thin film are [Formula: see text]0.667[Formula: see text]V and [Formula: see text][Formula: see text]cm[Formula: see text], respectively, as deduced from Mott–Schottky studies. The photoelectrochemical (PEC) behavior of the CdSe thin film exhibited an enhanced photocurrent density at about 0.35[Formula: see text]mA/cm2 vs. Ag/AgCl.