High performance photoelectric responses of nanocrystalline WO 3 film to humidity irradiated by UV light

In this work, photoelectric responses of nanocrystalline WO 3 film to humidity under UV light irradiation were investigated. Nanocrystalline WO 3 film with porous structure was prepared on Al 2 O 3 substrate by the technology of screen printing and the subsequent heat treatment. The as-prepared nanocrystalline WO 3 film was characterized with X-ray diffraction (XRD) and field-emission gun scanning electron microscopy (FE-SEM). The time-dependent photoelectric responses of nanocrystalline WO 3 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 WO 3 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 WO 3 to humidity will provides a new insight into the design and fabrication of advanced photo-activated humidity sensors.