Research On Working Mechanism And Performance Of Triboelectric Nanogenerator Based On All-Inorganic Perovskites

The triboelectric nanogenerators(TENG)has become an excellent energy harvesting device due to its easy-to-operate structure,low cost and wide range of applications.Perovskite has been proven to be a good choice for triboelectric dielectric materials in TENG,but its triboelectric behavior and charging affinity are still unclear.The focus is on the triboelectric properties and charge transport mechanism of inorganic CsPbI2Br,CsPbBr3 and CsPbCl3 perovskites in the vertical contact-separation mode.The main research contents are as follows:(1)Film’s preparation and characterization:Firstly,a multi-step spin-coating method is used to prepare all-inorganic halogen perovskite films,and the films are analyzed using related characterization methods.Secondly,the surface potential of the three halide perovskites is simulated using COMSOL software.The simulation results show that the potentials of CsPbCl3,CsPbBr3 and CsPbI2Br are 428 V,356 V,408 V,respectively.(2)Electrical output performance research:the electrical signal of the test results decreases first and increases then,CsPbI2Br(Voc=225 V,Isc=24.33 μA,Qsc=75.2 nC,power=1.54 W·m-2),CsPbBr3(Voc=183 V,Isc=21.56 μA,Qsc=66.8 nC,power=1.26 W·m-2),CsPbCl3(Voc=257 V,Isc=27.87μA,Qsc=79.8 nC,power=3.06 W·m-2),and films have excellent stability.In addition,the polarity of different perovskites is determined by the quality factor(FOMp).In addition,the polarity of different perovskites is determined by the figure of merit(FOMp)as CsPbBr3(the most negative)<CsPbI2Br<CsPbCl3(the most positive).Finally,the structure combined with the bridge rectifier can light up 80 LED lights,and the photoelectric detection and pressure performance of the perovskite-TENG are studied.(3)Research on charge transfer mechanism:The output signal is systematically analyzed from the aspects of surface roughness,surface potential,bond energy,electron binding energy,dielectric properties and carrier mobility,with emphasis on the influence of the crystal’s special asymmetric octahedral structure on the output performance.The calculation results of the surface energy and spontaneous polarization of the perovskite show that CsPbCl3 rather than CsPbBr3tends to retain the(110)crystal plane,while the polarization direction of the orthorhombic perovskite is[110].With the substitution of halide ions,the spontaneous polarization of CsPbBr3 crystal increased from 0.47 Ry a.u.to 0.52 Ry a.u.(CsPbCl3).Due to the increased spontaneous polarizability,the built-in electric field of the perovskite is enhanced,at the same time,the remaining frictional surface charge increases,which helps to improve the performance of triboelectric power.Finally,the COMSOL software was used to simulate the surface potential of the TENG structure based on the all-inorganic perovskite,and the calculated results were consistent with the experimental results.This paper not only uses the conventional charge transfer mechanism to analyze the output performance,but also focuses on using the spontaneous polarization of the material to adjust the crystal plane,and ultimately achieve high-performance output.This work enriches the triboelectric series and provides a new way for the application of new perovskite materials in the field of mechanical energy collection.