Electrosynthesis of MoTe2 Thin Films: A Combined Voltammetry-Electrochemical Quartz Crystal Microgravimetry Study of Mechanistic Aspects

Abstract

Molybdenum telluride (MoTe2) belongs to the family of layered transition metal dichalcogenides (TMDs) with unique optical, optoelectronic, structural properties and potential applications in a wide array of technologies related to solar energy conversion, optoelectronics, lubrication, and hydrogen production. Here, electrodeposition is shown to be a facile method for the synthesis of MoTe2 in bulk (i.e., not exfoliated) form. The electrosynthesis of MoTe2 films and the underlying compound formation mechanism were investigated for the first time using linear sweep voltammetry (LSV) combined with electrochemical quartz crystal microgravimetry (EQCM). A Te-modified electrode in an electrolyte containing molybdenum precursor species, a MoO x -modified electrode in tellurium precursor-containing electrolyte and a variety of control experiments were employed to elucidate the electrodeposition mechanism of MoTe2 films. Electrogeneration of HTe− was the key step in MoTe2 film formation which occurred by the reaction of electrodeposited MoO x with HTe− generated by electroreduction of Te or HTeO2 +. Thermodynamic aspects of this reaction are finally presented.