Electrodeposition of cadmium selenide based photoanodes from TOMAC/Formamide ionic liquid for photoelectrochemical applications

Abstract

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 studies, 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 a 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 eV. The flat-band potential and carrier density values of CdSe thin film are − 0.667 V and 6.13 ×1016 cm− 3 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 mA/cm2 vs. Ag/AgCl.