Research Of The Mwnts Benzene Series Vapor Sensor

Because of the special characteristics of large surface-volume ratio, abundant hole structure and high surface activity, carbon nanotubes (CNTs) has drawn much more attention by many researchers. They can be used as gas sensing material, so gas adsorption process with high sensitivity, fast response time and advantages of long-term stability. Thus, they exhibit broad application prospects.This article focuses on carbon nanotube gas sensor response characteristics of benzene gas. As the carbon nanotube film has a pore-like structure, benzene gas molecules can congregate due to molecular adsorption and capillary condensation. As the benzene gas molecules adsorbed, the dielectric constant of carbon nanotubes changes with the gas concentration. Thus, capacitance change of the sensor could test the gas concentration changes. Based on the above concept, we choose the screen printing to prepare carbon nanotube benzene sensor adulterated with low temperature glass power, films doped benzene sensor. With the requirements of the gas test, we design a benzene sensor test device which meets air tightness, concentration control, well observation and other requirements of the carbon nanotubes.Inter-digital capacitive benzene Multi-walled carbon nanotubes (MWNTs) sensor, whose electrode is made by evaporation and photolithography technology and the films are made by screen printing technology is introduced in this paper. By testing benzene carbon nanotube sensor in different frequencies and considering the sensitivity and stability factors, we selected the test system at a frequency of 1kHz. Characteristics of sensor's sensitivity response time, recovery time repeatability, temperature performance are evaluated with benzene, toluene, xylene. Test results show that the benzene carbon nanotube sensor performs well. At the same temperature conditions, it is most sensitive to xylene. Finally, chemical modification of carbon nanotubes to improve sensor performance was tested for its effectiveness. The results showed that chemical modification can improve the sensor sensitivity and stability of the low concentration measured object.