Electrodeposition of MoS2 from Dichloromethane

Abstract

The electrodeposition of MoS2 from dichloromethane (CH2Cl2) using tetrabutylammonium tetrathiomolybdate ([NnBu4]2[MoS4]) as a single source precursor is presented. The electrodeposition of MoS2 from CH2Cl2 requires addition of a proton donor to the electrolyte and trimethylammonium chloride (Me3NHCl) was used for this purpose. Electrochemical Quartz Crystal Microbalance (EQCM) experiments have been employed for a detailed study of the electrochemical mechanism and to study the role of the proton donor. EQCM reveals cathodic electrodeposition of MoS2 and anodic deposition of MoS3 as well as an additional corrosion process where the deposited MoS3 strips back into solution. The electrodeposited MoS2 films are amorphous in nature. All the films were found to be homogeneous in composition across the electrode area and to be reproducible between experiments. Annealing of the as-deposited films under a sulfur atmosphere results in crystalline MoS2 as confirmed by energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy and X-ray diffraction. The deposited films were smooth and planar, as observed with scanning electron microscopy (SEM), indicating a layer-by-layer growth typical of transition metal dichalogenides.