Visible Light Activated Tungsten Oxide Sensors for NO2 Detection at Room Temperature

The sensing characteristics of tungsten oxide (WO3) gas sensors under visible light illumination have been investigated at room temperature. Sensing measurements were performed on sputtered (thin-film) and screen-printed (thick film) WO3 layers towards sub-ppm NO2. Light sources with different wavelength were employed to illuminate the WO3 sensors. The results showed that the light illumination effectively improved the NO2 sensing properties and the 475 nm light (blue colour) was the most effective for the WO3 sensors.