UV Light Affects the Gas Sensitive Properties of Tungsten Oxide

Researchers have found that ultraviolet and visible light can provide energy for the surface chemical reaction of tungsten oxide gas-sensitive materials, thereby accelerating the rate of chemical reactions, thereby improving its gas-sensing properties. The study found that ultraviolet light affects the gas-sensitive properties of tungsten oxide gas mainly through two aspects:

(1) UV light irradiation can cause dissociation of the target gas on the surface of the tungsten oxide gas sensing layer and increase the chemical adsorption site on the surface of the tungsten oxide gas sensor.

(2) UV irradiation will increase the surface electron-hole pair of tungsten oxide gas, thereby increasing the number of carriers and improving gas-sensing performance. The room temperature gas-sensitivity of nitrogen dioxide gas sensor to tungsten dioxide gas sensor under ultraviolet irradiation was tested. Its sensitivity is 15.4, response time and recovery time are 2.5 s and 18.1 s, respectively.

The relationship between the sensor sensitivity and the UV power density was found. The results show that the gas sensing performance of the tungsten oxide gas sensor under the appropriate UV light conditions is comparable to that of the nitrogen dioxide under high temperature conditions. Tungsten oxide can also be excited with visible light at room temperature. Compared to ultraviolet light, visible light consumes less power and is more widely sourced. Using a screen printing method, a tungsten oxide gas sensor can be prepared, and the influence of different wavelengths of visible light on its gas sensing performance at room temperature is studied. The results show that tungsten oxide has the best gas sensitivity and sensitivity of 2.9 when irradiated with a blue light source. The response and recovery times were 14.9 minutes and 18.3 minutes, respectively, which is equivalent to the performance of the sensor heated to 200-300 °C.

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