Trap Distribution and Conductivity Synergic Optimization of High-Performance Triboelectric Nanogenerators for Self-Powered Devices

Abstract

Exploring effective methods of increasing the triboelectric charge density of tribo-materials to boost the output performance of triboelectric nanogenerators (TENGs) is crucial for expanding their practical applicability in modern smart devices. This study discusses the incorporation of various polymeric dielectric layers between the tribo-material and electrode components of TENGs, which improved their electrical output performance to varying degrees. The TENG demonstrating the largest improvement (1200 V) was obtained after adding a polyimide layer. The analysis presented herein suggests that incorporating a dielectric layer with high trap energy means that more charges are held in deep traps; thus, such TENGs demonstrate the best electrical performance. Additionally, when a dielectric layer is added to the triboelectric material, the enhanced TENG output is related to the volume conductivity of the triboelectric material, but not to its electronegativity or surface structure. Finally, the optimized TENG developed in this work demonstrates energy harvesting capabilities and can function as a self-powered sensor applied in an intelligent housing system and as an emergency fall detection/alert system for the elderly and the sick.

High-Performance Polyimide-Based Water–Solid Triboelectric Nanogenerator for Hydropower Harvesting

“…By adding a PI as an intermediate layer between the PS layer and the electrode layer, more trapping sites are provided and negative charges are trapped and stored in the PS/PI layer (Figure 4b), which will reduce charge neutralization and significantly increase the output performance. 48,49 On the one hand, adding a PI layer provides more electron trapping sites and gives a better charge capacity. On the other hand, the thickness of the PI layer is important in the output performance of water−solid TENGs.…”

“…Due to unequal energy levels, the PI films have many electron trapping sites and were therefore chosen as the intermediate layer to prepare the water–solid TENG with high output performance. − Figure a shows the whole of the fabrication processes of the water–solid TENG with PI as an intermediate layer (PI-TENG). First, it involves the preparation of a thin PS film onto the PI layer by the spin-coating method, and the contact angle of the PS/PI film is about 101.1° (Figure S1 in the Supporting Information), exhibiting a good hydrophobic property.…”

Smart Textile Triboelectric Nanogenerators: Prospective Strategies for Improving Electricity Output Performance

“…The increment of permittivity improves the injected charge density and internal capacitance of the TENG, thus resulting in the enhancement of output power and the reduction of matching impedance, respectively. The charge trapping mechanism combined with increased conductivity for improving the output performance of TENGs is illustrated in Figure 8f [122]. When there is no PI layer and MWCNTs, the triboelectric charges with purple dots generated by TPU are generally trapped in shallow traps, which is easy to combine with the induced charges with green dots on the electrode and charged ions or particles with blue dots from the air, resulting in obvious charge loss and low output.…”

“…(f) Schematic illustration of charging trapping mechanisms. Reproduced with the permission of[122], copyright 2021, American Chemical Society.…”

Flexible Layered-Graphene Charge Modulation for Highly Stable Triboelectric Nanogenerator

“…The triboelectrification process involves charge generation, charge storing and charge decay of triboelectric materials [ 15 ]. Therefore, selecting the proper triboelectric materials is the key to improve the output performance of flexible TENGs.…”