High performance photoelectric responses of nanocrystalline WO3 film to humidity irradiated by UV light

In this work, photoelectric responses of nanocrystalline WO3 film to humidity under UV light irradiation were investigated. Nanocrystalline WO3 film with porous structure was prepared on Al2O3 substrate by the technology of screen printing and the subsequent heat treatment. The as-prepared nanocrystalline WO3 film was characterized with X-ray diffraction (XRD) and field-emission gun scanning electron microscopy (FE-SEM). The time-dependent photoelectric responses of nanocrystalline WO3 film were studied by exposing it to a wide humidity range of 20–80% relative humidity (RH) at room temperature under UV light irradiation. High performance photoelectric responses of nanocrystalline WO3 film to humidity were observed. To illustrate it, a possible explanation for the photoelectric responses to humidity was proposed. On the basis of the results, the high performance photoelectric responses of WO3 to humidity will provides a new insight into the design and fabrication of advanced photo-activated humidity sensors.