Electrodeposited SnS thin films from aqueous solution

Abstract

Considerable efforts have been made in recent years in the search for low-cost materials for solar energy conversion. Among the materials of great interest are polycrystalline metal chalcogenides. These can be synthesized by means of low-temperature chemical precipitation or vapour deposition techniques, as described in previous works [1, 2]. The materials may also be electrosynthesized, either cathodically [3‐5] or anodically [6‐8] from an aqueous or nonaqueous medium. Electrochemical methods, especially those performed in an aqueous medium, have recently received enormous attention due to their simplicity and cost effectiveness [9‐15]. In addition, they have the advantages of being low temperature processes, with low material wastage and with the possibility of using lower grade materials. This method has been extensively applied in the preparation of CdS and CdSe thin films. We report here the possibility of cathodic electrodeposition of another promising compound, tin sulphide (SnS), from aqueous solution. The electrodeposition was carried out on either titanium or an indium-doped tin oxide (ITO) glass substrate in a standard three-electrode cell. A saturated calomel electrode (SCE) or sometimes an Ag AgCl electrode was used as the reference electrode, while platelet or spiral Pt (99.9%) was used as the counter electrode. The deposition potential was controlled by an EG&G Princeton Applied Research (PAR) Versastat driven by model 270 Electrochemical Analysis System software. The substrate was polished and chemically and ultrasonically cleaned before being used. The electrodeposition bath was prepared from anhydrous SnCl2, sodium thiosulphate (Na2S2O3) and disodium ethylenediaminetetra-acetic acid (EDTA) salts using N2purged purified water from a Milli-Q water purification system. The resultant solution was acidified to a pH of about 1.5. The solution was continuously deaerated with N2 during electrodeposition. Prior to electrodeposition, cyclic voltammetry was run in order to determine the viable potential and to elucidate the electrochemical processes at the