High performance oxygen sensor utilizing ultraviolet irradiation assisted ZnO nanorods under low operation temperature

This paper presents a novel ultraviolet (UV) irradiation assisted nanostructured ZnO film for high performance oxygen sensing under a low working temperature. The UV irradiation greatly increases the number of the excited electrons to attract the high electron negativity molecule of oxygen. The response for detecting the oxidation gases can be achieved without using the high catalytic temperature. Nanorod ZnO structures with high exposing area are synthesized on a glass substrate with interdigital sensing electrodes utilizing the developed two-stage sol-gel and hydrothermal processes. An 80 mW LED with the emission wavelength of 370 nm is then used to enhance the sensing performance of the nanostructured ZnO film. Results indicate that the sensing performance of the nano ZnO oxygen sensor is greatly improved. The oxygen sensor can work at a low temperature of 50°C with the assist of UV exposure, which is much lower than the working temperature of typical solid state metal oxide sensors of around 350°C. The response of the UV-assisted ZnO film shows 4.66 times larger than the same film without UV exposure. The method developed in the present study provides a simple yet high performance method for oxygen sensing under low operation temperature.