Novel Triboelectric Nanogenerators And Their Applications In Self-Powered Sensing

The rapid development of modern technology has promoted the progress of society,and the diverse electronic products have brought great convenience to people’s daily lives.With the advancement of technology,electronic devices are gradually moving towards miniaturization and intelligence.Especially with the vigorous development of Internet of Things(IoT)technology,the number of smart micro-sensors has increased sharply.In addition,with the improvement of living standards,people are paying more and more attention to their body health,and a large number of wearable devices and implanted sensors for health monitoring have emerged.The problem that people must solve urgently is powering these micro-scale electronic devices with special application scenarios.In recent years,the development of nano-energy technology and self-powered sensors has provided ideas for solving this problem.Among them,the triboelectric nanogenerator(TENG)has attracted much attention due to its simple structure,cost-effective fabrication processes,and high output performance.It has broad application prospects in energy harvesting and self-powered sensing systems.In this article,we mainly focus on three aspects of improving TENG theoretical model,improving TENG performance and constructing TENG-based self-powered system.In this paper,the chemical composition modulation and ion migration of organic-inorganic hybrid perovskite(PVK)are proposed to improve the performance of TENG.The chemical composition modulation can change the conductivity type of PVK,when the proportion of organic components is high,it performs p-type material,and when proportion of inorganic components is high,it performs n-type material.Ion migration produces localized ion-doping near the surface of PVK,positive ion-doping makes the surface electron affinity decrease,and negative ion-doping makes the surface electron affinity increase.When PVK film works as a positive friction material,the high proportion of organic components and positive ion-doping can enhance the performance of TENG,and when it works as a negative friction material,high proportion of inorganic components and negative ion-doping can increase the performance of TENG.The proposed performance-enhanced TENG has been successfully applied to energy harvesting and storage,powering simple circuits,etc.Next,a TENG-based self-powered probe is developed to study the influence of ion migration and ferroelectric polarization on the surface energy band structure of hybrid perovskite.On the one hand,the results explain how the ferroelectric polarization,as well as the combination of ion migration and ferroelectric polarization,enhancing the performance of TENG.On the other hand,the results explain how ion migration and ferroelectric polarization enhancing the performance of hybrid perovskite solar cells.Finally,based on the experimental results,it is concluded that the output of the TENG-based self-powered probe is linearly related to the surface potential difference between the probe and the material to be tested,and is also linearly related to the surface charge density of the material to be tested.Then,a theoretical model is proposed when the contact electrification effect and the p-n junction effect exist simultaneously in the TENG system,which provides a theoretical basis for designing high-performance TENG and improving the output of TENG.For contact electrification effect,when two material contact each other,charges transfer from one to another due to the electron affinity difference of two materials.For p-n junction effect,the output is determined by the changes of depletion layer width near the material surface.The outputs generated by the contact electrification effect and the p-n junction effect is separated on the time scale,which makes it possible to harvest energy by using both two effects.Finally,a self-powered ion concentration detection system is developed based on the ferroelectric materials(PZT).The two main problems faced by current polymer-based droplet energy harvesters are that the surface charge initialization process is complex and the surface charge is easy to lose.PZT material have uniform and stable surface charges due to self-polarization,which can solve these problems,and they can be used to fabricated droplet-based energy generators and high-performance self-powered liquid detection systems.When a droplet is falling,the change of the active contact area between droplet and PZT drives the charge to flow,and realize the mechanical energy to electrical energy conversion.Changes in droplet properties change the ability of the droplet-based energy generator to drive charges,for example,the increase of ion concentration increases the droplet-based energy generator’ s ability to drive charges.Based on this principle,we developed a self-powered ion concentration detection system,and successfully used it to detect the ion concentration of solution.In summary,in this paper,we focus on the theoretical models of TENG,strategies to enhance TENG performance,and the applications of TENG-based self-powered systems.The results enrich the theoretical model of TENG and provide a reference for understanding the working mechanism of TENG and the design of high-performance TENG.And we proposed a variety of strategies to enhance performance of TENG and have fabricated high-performance TENG based on these strategies.And then,we developed TENG-based self-powered sensor systems,which have been successfully applied to the measurement of material’ s surface electrical properties and the detection of the ion concentration of solutions.