Research On Triboelectric Nanogenerator Based On Semiconductor Silicon

At present,energy and environmental problems are emerging one after another,and triboelectric nanogenerators（TENGs）have been favored by people because of their ability to collect tiny energy anytime,anywhere,and have become one of the key topics in the scientific community in recent years.In previous studies,insulator materials and metal materials have been widely used as friction layer materials for TENGs,while semiconductor materials with richer functions and greater controllability are relatively less used as friction layer materials in TENGs.In this paper,a very common semiconductor,silicon（Si）,is selected to explore the performance of triboelectric nanogenerators when it is used as a friction layer material:（1）AC triboelectric nanogenerator based on semiconductor siliconIn this work,we design a Si-PTFE structure based TENG（SP-TENG）with Si and polytetrafluoroethylene（PTFE）as two friction layer materials.First of all,we simulate the change of the surrounding potential of the two friction layers of the vertical contact-separation mode SP-TENG from contacting to gradually moving away through COMSOL Multiphysics simulation,showing the working principle of TENG.Next,we investigate the effects of movement speed and relative impact depth on the output performance of the vertical contact-separation mode SP-TENG: within a certain range,the higher the movement speed and the relative impact depth,the higher the output performance.In addition,we enrich and refine the position of Si in the triboelectric series by comparing the output properties of SP-TENG composed of PTFE with different doping types of Si as a tribolayer: p-type silicon is closer to the PTFE side,while n-type silicon is closer to the nylon side.Finally,we improve the output performance of SP-TENG by means of ion implantation.This work lays the foundation for the application of silicon in TENGs.（2）DC-TENG based on semiconductor siliconAs a newly discovered physical phenomenon,tribovoltaic effect has potential applications in various fields.Here,we systematically study the relationship between interface characteristics and output performance by TENG（CS-TENG）based on conductor semiconductor structure.Based on semiconductor physics and mathematical models,a formula is derived to qualitatively explain the effects of contact area,load force and semiconductor surface density of states on the output performance of CS-TENG.The experimental results are in good agreement with the theoretical analysis.Next,we investigate the effect of substrate hardness on the output performance of CS-TENG: within a certain range,the greater the substrate hardness,the higher the output performance.In addition,we discuss the contribution of interface electric field and interface magnetic field to tribovoltaic effect.By using epitaxial silicon wafer,the built-in electric field near the CS interface can be adjusted to suppress the composite effect of friction voltage,and the short-circuit current of CS-TENG can be increased by 66.83%.This work paves the way for the electrode design and better output performance of flexible DC-TENG in the future.