The VOCs Sensor Based On CNT-FET

The VOCs in the exhaled breath reflect the health of the our body and can be used for the evaluation of various diseases.Therefore,the development of a sensor system that integrates with human skin and measures the composition of human respiratory gases in real time has important medical value.However,at present most of the testing equipment are monitoring oral exhaled gas.These structures and functions are complicated,hard to miniaturization.It can be susceptible to gas pollution caused by bacteria in the oral cavity.Monitoring of nasal exhaled gas components is less polluting and has better reliability for disease assessment,but there is no wearable equipment for nasal monitoring due to limitations in measurement areas and gas collection methods and interfering to normal breathing.Based on the above analysis,combined with flexible electronic,a nasal exhaled gas measurement based on CNT-FET is proposed.This paper mainly introduces these following contents:Firstly,this paper introduces the principle and specific preparation process of carbon nanotubes and CNT-FET.In the processing,the combination of flexible electronic processing technology and dispersion carbon nanotubes is used to realize the composition of the device.Secondly,this paper designs a complete gas generation system,in which the liquid VOCs were pushed into the VOCs generator by the syringe pump,and the VOCs gas were introduced into the vacuum test chamber to form a test system for isolating the external environment.Thirdly,this paper designs a hardware platform for simultaneous measurement of multiple sensors to ensure accurate measurement of electrical signals in the vacuum test chamber and real-time measurement of up to ten sensors.Finally,the response of the sensor to VOCs was tested with acetone as an example.It was found that the adsorption of the specified concentration of acetone gas on the conduction characteristics of the carbon nanotubes,thereby realizing the real-time measurement of the acetone gas.