WO3 nanowires for optoelectronic and gas sensing applications

WO3 nanowires (NWs) were grown by vapor transport for potential applications in light-emitting diodes (LEDs) and NO2 gas sensing. The products were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy, spectrophotometer, and photoluminescence (PL) measurements. XRD revealed the formation of hexagonal WO3 single-crystal phase. Scanning and transmission electron micrographs analyses showed that the hexagonal WO3 has nanowires in shape with diameters of 30-40 nm and lengths extended to 4 mu m. The calculated optical band gap was 3.26 eV, and the Urbach energy was 293 meV. The PL emission revealed two strongest peaks at 365 and 421 nm, which may have significant potential applications in LEDs. The sensing properties of the obtained WO3 NWs were determined for NO2 gas and other harmful gasses. The WO3 NW sensors were highly sensitive that could detect NO2 at the sub-ppm level.