Preparation, characterization and sensing properties of WO3-deposited over LED

Abstract

Tungsten oxide (WO3) nanoparticles were successfully deposited by the SILAR technique on the commercially available light-emitting diode (LED) with a wavelength of approximately 370–400 nm. X-ray diffraction (XRD) studies confirmed the thermally stable monoclinic phase of deposited WO3, and morphological analysis showed the formation of nanoparticles with pores and voids which are essential to improve the overall sensing performance of the WO3. The sensing characteristics of prepared WO3 were tested, and WO3 showed a better response towards 20 ppm of formaldehyde vapor. The formaldehyde response was doubled along with less response time under the LED illuminated condition. The WO3 is highly selective to formaldehyde under a mixed vapor environment. The response and recovery time was found to be 32 s, and 38 s was achieved under the LED illuminated state. The role of light energy in increasing the concentration of reactive site was discussed, and a photo-assisted formaldehyde detection mechanism of WO3 was proposed and discussed.