Research On Self-Powered Gas Sensors Based On Nano-Zinc Oxide And Their Characteristics

In recent years,with the continuous research and innovation of nano materials,new gas sensors are more and more pursuing the intelligence,miniaturization,low power consumption and portability of devices.Nanogenerator can transform the mechanical energy in the living environment into electrical energy to provide energy for the system work,and put forward a new solution for the power supply problem of nano devices.Therefore,the development of self-powered nanotechnology has great practical significance for the development of sensors.ZnO is a direct wide band gap semiconductor with piezoelectric,gas sensitive and photosensitive properties.Its preparation method is relatively simple and its morphology and structure are controllable.This paper is devoted to the research of self-powered gas sensor based on nano ZnO.By theoretical simulation and preliminary experiments,ZnO nanomaterials with different morphologies are prepared.By combining with different materials,the piezoelectric properties and gas sensing properties of ZnO nanomaterials are studied.The films were characterized by XRD,XPS,SEM and TEM.The nanogenerator is made of piezoelectric or triboelectric materials to provide power for the gas sensor.The sensor can work without external power supply,which effectively solves the problem of energy consumption caused by external power supply for the traditional sensors.In this paper,Ag/ZnO nano array self-powered ethanol gas sensor was prepared by hydrothermal method.The piezoelectric output of the Ag/ZnO nanowire array is not only the power supply for the self-powered sensor,but also the sensor signal for detecting different concentrations of ethanol gas at room temperature.The results show that the response of the sensor to ethanol is up to 90%.Using Al-PVA and PI to prepare a tribo nanogenerator,using the energy generated by it as a power source,the gas sensitivity performance of the Pd@ZnO/Mo Se₂composite film sensor exposed to nitrogen dioxide（NO₂）gas at room temperature was studied.The results show that the thin film sensor has good NO₂sensitivity.The PVDF/MXene nanofibers were synthesized by high-voltage electrospinning,and the PANI/ZnO composite film ammonia（NH₃）sensor was driven by a PTFE-PVDF/MXene piezoelectric triboelectric hybrid nanogenerator at room temperature.The results show that the response of the sensor at10 ppm ammonia concentration is 96.1%.Finally,the sensitive mechanism of the sensor is analyzed based on the principle of oxygen adsorption and desorption on the surface of the sensitive film,Schottky junction and heterojunction theory.This paper explores the self-powered gas sensor based on ZnO nanomaterials,designs three kinds of nanogenerators,realizes the power-free self-supply system,reduces the energy consumption of the device,greatly improves the adaptability of the device,makes the device more portabl.The nanogenerator acts on the ethanol,NO₂and NH₃gas sensors based on ZnO nanomaterials to detect their gas sensitivity characteristics,and collect the mechanical energy of human body by using nanogenerator,which provides new applications for the sensor in health care and environmental detection.