Research Of Self-powered Resistive Gas Sensor Based On Triboelectric Effect

Emissions of exhaust gas in our life cause air pollution and seriously threaten people's health.At the same time,human beings have been facing energy problems since the Industrial Revolution.As a result,it is very crucial to study and develop gas sensors with advantages of low-cost,low power consumption and high sensitivity.Friction charge is ubiquitous in our life,which is considered as a negative physical phenomenon in many cases.However,the invention of triboelectric generators?TENG?significantly broads the applications of friction charge.The Au interdigital electrodes can be deposited combined with a gas-sensitive film to fabricate a resistive gas sensor.As a new type of gas sensor,self-powered gas sensor is based on the combination of triboelectric generators and a resistive gas sensor,which brings about many advantages,such as low cost,low power consumption,robustness and so on.Triboelectric generators is an energy collection device of self-powered sensors.In this paper,in order to detect nitrogen dioxide?NO₂?gas,a resistive self-powered gas sensor based on coupling of contact electrification and electrostatic induction is prepared.The main contents are as follows:Firstly,triboelectric generators with different materials and different sizes were fabricated,which base on vertical contact-separation mode.The mechanisms of open circuit voltage,short circuit current and resistance load effect of triboelectric generator were studied,respectively.In addition,the effects of the friction area sizes and the contact materials on the performance of the triboelectric generators were investigated.The experimental results show that the large sizes and distance contribute to the enhancement of the performance of the triboelectric generators.Also the difference in the ability of obtaining electrons of the materials and the contact speed influence the peak-to-peak value of the output voltage and current.Secondly,a NO₂ self-powered gas sensor based on zinc oxide?ZnO?material was fabricated with PTFE and Cu materials with areas of 100 cm2 as the the contact-separation triboelectric generator.Under UV-assisted conditions,devices was found to have an optimum film thickness for NO₂ response.2m L ZnO suspension of alcohol with 3mg/m L concentration was the best one for the experimental.The device has a slope of fitting line about 0.167 ppm-1,and the relative response is up to 14.8 upon exposure to 100 ppm NO₂ at room temperature.Finally,five types of devices were fabricated using zinc oxide?ZnO?and reduced graphene?RGO?with the optimum film thickness.The response,repeatability and selectivity of the prepared devices were tested.The results show that the RGO and ZnO hybrid device has the highest slope of fitting line of 0.196 ppm-1,and its relative response is 16.7 at 100 ppm NO₂.The hybrid film based device has larger selectivity but slightly poorer repeatability in comparison with the pure ZnO device.