Research On Self-powered Sensors Based On Nanogenerator

With the rapid development of electronic and information technology,wearable electronic devices,artificial intelligence,Internet of Things and other high-tech technologies with micro-nano electronic devices as the core have gradually entered people’s daily life.Considering the inherent defects of traditional batteries such as limited capacity and frequent maintenance,building a self-powered system that can run stably for a long time,portable,and has multiple functions is an inevitable requirement for electronic equipment in the era of big data.Nanogenerator,as an emerging micro-energy technology that can efficiently convert mechanical energy into electrical energy,has many unique advantages such as simple structure,diverse material selection,easy transplantation,and high electromechanical conversion efficiency.It has shown great potential in realizing long-term stable energy supply of micro-nano electronic devices.However,how to effectively combine nanogenerators and sensing systems to achieve effective sensing and feedback of changes in external environmental information without an external power supply,that is,to construct a self-powered sensing system.It will have important research value in many fields such as human motion monitoring,environmental monitoring and so on.In this paper,a triboelectric nanogenerator based on a micro-nano-hierarchical wrinkled structure is designed and studied,and as a high-performance self-powered pressure sensor,it achieves high sensitivity and wide detection range.The self-healing properties were then combined with nanogenerators to fabricate self-healing triboelectric nanogenerators and fully self-healing piezoelectric nanogenerators,which were used in self-healing,selfpowered pressure sensors.Meanwhile,the feasibility of triboelectric nanogenerators as selfpowered gas sensors is demonstrated by utilizing polyaniline nanostructure-based triboelectric nanogenerators as self-powered ammonia gas sensors.Finally,the performance of the self-powered ammonia sensor based on triboelectric nanogenerators was further improved by constructing a three-dimensional porous structure.The main research results of this paper are as follows:(1)The preparation of triboelectric nanogenerators with micro-nano-hierarchical wrinkled structure was studied.By comparing the structure and morphology of microscopic wrinkled,the generation mechanism of the wrinkled structure is explored,that is,the result of the redistribution of compressive stress through buckling.Using 40,000 periodic contact separation tests,we demonstrate the high stability of the triboelectric nanogenerator based on PDMS/Zn O NWs micro-nano-hierarchical wrinkled structure as a self-powered pressure sensor.At the same time,as a high-performance self-powered pressure sensor,the pressure sensitivity in this work can be divided into two regions: a low-pressure region(<25 k Pa)with a sensitivity of 4.14 V/k Pa and a high-pressure region(25-476 k Pa).Compared with the self-powered pressure sensor based on the wrinkled structure,the pressure sensitivity of these two regions is increased by 2.91 times and 3 times,respectively,with the assistance of the Zn O piezoelectric potential and the rough surface.Finally,self-powered pressure sensors are used to monitor many types of human motion.(2)A self-healing triboelectric nanogenerator with a hierarchical wrinkled structure was prepared by combining the hierarchical wrinkled structure with a self-healing flexible substrate.Controlling the time of sputtering Zn O and hydrothermally growing Zn O nanowires,the output of the final fabricated triboelectric nanogenerator was 83.8 V and 6.03μA.The electrical properties were tested by multiple cutting and repairing cycles to further verify the outstanding self-healing effect of the flexible substrate and the stability and feasibility of the device as a self-healing self-powered pressure sensor.Finally,the device was combined with the movement of the human body swing arm to effectively monitor the movement of the human body swing arm.(3)The concept of fully self-healing piezoelectric nanogenerators is proposed,and piezoelectric nanogenerators with efficient self-healing properties are designed and fabricated.PZT piezoelectric ceramic particles are used as piezoelectric material,PDMSIU-MPU is used as the main body of self-healing material,and silver nanowire cross-linked network is used as electrode.The nanogenerator can achieve the maximum output at a mass ratio of 70 wt% piezoelectric ceramics,with a voltage and current of 3.2 V and 56.1 n A,respectively.And it can still maintain more than 90% of the output effect after self-healing.Finally,a 9-grid sensing array is assembled as a bionic electronic skin self-powered pressure sensor to monitor the point and force of different stress parts.(4)A self-powered ammonia gas sensor was designed and fabricated with a polyanilinebased triboelectric nanogenerator.The output voltage and current were 41 V and 0.2 μA,respectively.As a self-powered ammonia gas sensor,it can monitor ammonia with a minimum concentration of 20 ppm at room temperature,and in 20-1000 ppm ammonia atmosphere,the sensitivity is about 0.046 %/ppm.(5)In order to further improve the sensing performance of self-powered ammonia sensor,a high-performance self-powered ammonia sensor based on triboelectric nanogenerator was designed and fabricated by combining cellulose membrane with three-dimensional porous structure and polyaniline material.First,the energy harvesting as a triboelectric nanogenerator is studied to realize the charging of commercial capacitors.Then,through the device structure design,the response mechanism of the self-powered ammonia sensor was studied.In the atmosphere of ammonia gas,the change of the electron gain and loss ability of the polyaniline material,the change of the electron transport ability of the electrode layer and the synergistic effect of the three-dimensional porous structure,the self-powered ammonia gas sensor obtains the best sensing performance,the minimum detection limit is100 ppb,and the response rate was 15.1%.Among them,in the concentration range of 0.1-2000 ppm,the average sensitivity is 0.0405 %/ppm.