Tungsten dichalcogenides as possible gas-sensing elements

Possible application of tungsten dichalcogenides as gas-sensing elements is discussed in this paper. The experimental results on sensitivity of pristine and niobium doped WS2 and WSe2 to acetone and ethanol gases are presented. Polycrystalline powder specimens were obtained by high temperature solid-state synthesis from the stoichiometric mixture of pure elements. Two types of samples were studied: 1) tablets pressed at 1.5 GPa to form bulk samples and 2) thin films prepared from 35% ethanol-water colloidal dispersions by their filtration onto membrane filters (pore diameter is 20 nm). The electrical resistances of the samples were shown to be increased in the presence of ethanol and acetone gases at room temperature, thereby revealing positive response to reducing gases.