Photoelectrochemical study of TiS 3 in aqueous solution

Abstract

TiS 3 single crystals have been grown by chemical vapor transport. They were characterized by X-ray diffraction and measurement of their electronic transport properties. A photoelectrochemical study shows both anodic and cathodic dark currents and anodic photocurrents. Flat band potentials and anodic corrosion p o te n tials in acidic and basic solutions and in the presence of an I − 3 I − redox couple have been determined from the onset of photocurrent and from the Schottky-Mott plot of capacitance. The flat band potential ex h ibits a pH dependence but is almost independent of the presenc e o f I − in solution. The stability of this material in a 1N H 2SO 4+ 1N I − 3 I − solution has been observed for a period of fourteen days with a photocurrent of approximately 1 mA cm 2 . A particular photocorrosion mechanism is reported. The reaction starts at the edges of the layer and proceeds toward the interior. These mechanisms are discussed in relation to the existence of two types of S atoms in the structure: sulfur dimers and S 2− ions.