Tungsten trioxide coatings prepared by inkjet printing of a water based formulation: structural characteristics and electrophotocatalytic properties

Abstract

Thin compact layers of monoclinic tungsten trioxide (WO3) were prepared through printing of a water soluble dopamine peroxo-tungstic acid complex (DoPTA). The effect of different layer thicknesses, achieved through the sequential overlapping of layers (from one to five), on the resulting structure and photo(electrochemical) properties was investigated. After a powder XRD analysis, 450 °C was determined to be the most suitable temperature for calcination due to the formation of a crystalline phase of WO3 within a relatively short time (after 1 h) and, at the same time, this temperature does not cause any damage to the glass substrates used for the deposition of the WO3 layers. Linear scanning voltammetry as well as chronoamperometry were used, with periodic illumination, to measure the influence of the number of layers on the final electro-photocatalytic properties. The thickness of the samples prepared ranged from 0.25 µm to 1.25 µm and the three-layer sample was found to have the best performance. It had a thickness of 0.83 µm, and the incident photon to current efficiency (IPCE) was calculated to be 40.8%.