Mixed Triboelectric and Flexoelectric Charge Transfer at the Nanoscale

Abstract

The triboelectric effect is a ubiquitous phenomenon in which the surfaces of two materials are easily charged during the contact-separation process. Despite the widespread consequences and applications, the charging mechanisms are not sufficiently understood. Here, the authors report that, in the presence of a strain gradient, the charge transfer is a result of competition between flexoelectricity and triboelectricity, which could enhance charge transfer during triboelectric measurements when the charge transfers of both effects are in the same direction. When they are in the opposite directions, the direction and amount of charge transfer could be modulated by the competition between flexoelectric and triboelectric effects, which leads to a distinctive phenomenon, that is, the charge transfer is reversed with varying forces. The subsequent results on the electrical power output signals from the triboelectrification support the proposed mechanism. Therefore, the present study emphasizes the key role of the flexoelectric effect through experimental approaches, and suggests that both the amount and direction of charge transfer can be modulated by manipulating the mixed triboelectric and flexoelectric effects. This finding may provide important information on the triboelectric effect and can be further extended to serve as a guideline for material selection during a nanopatterned device design.

A Triboelectric Nanocomposite for Sterile Sensing, Energy Harvesting, and Haptic Diagnostics in Interventional Procedures from Surgical Gloves

“…[ 58 ] As a result of mixed triboelectric and flexoelectric charge transfer at the interface between the rough coating and the slots, we can observe that charge transfer is reversed with material strain, when both effects are in opposite directions. [ 59 ]…”

Multilayered MoS2 Sphere-Based Triboelectric–Flexoelectric Nanogenerators as Self-Powered Mechanical Sensors for Human Motion Detection

“…32 Also, Qiao et al presented that both the amount and direction of charge transfer can be modulated by manipulating the mixed triboelectric and flexoelectric effects. 33 As mentioned earlier, the mechanism analysis and implementation of flexoelectric effect-based devices have been demonstrated along with the synergistic outcome of hybridization with the piezoelectric or triboelectric effects. However, the effective implementation, practical applications, and systematic mechanistic analysis of self-powered mechanical sensors based on the flexoelectric effect have not been comprehensively examined.…”

“…For instance, Kim et al reported flexoelectric-boosted electromechanical properties of piezoelectric nanoparticles using an induced built-in strain gradient in a heterogeneous core–sphere nanostructure of BaTiO 3 @SrTiO 3 . Also, Qiao et al presented that both the amount and direction of charge transfer can be modulated by manipulating the mixed triboelectric and flexoelectric effects . As mentioned earlier, the mechanism analysis and implementation of flexoelectric effect-based devices have been demonstrated along with the synergistic outcome of hybridization with the piezoelectric or triboelectric effects.…”

0.5 m Triboelectric Nanogenerator for Efficient Blue Energy Harvesting of All‐Sea Areas

“…The emerging triboelectric nanogenerator (TENG) is an indispensable way to convert mechanical energy into electrical energy, [ 9 , 10 , 11 , 12 ] successfully harvests diverse kinds of mechanical energy, [ 13 , 14 , 15 ] including wind energy, [ 16 , 17 , 18 ] water wave energy, [ 19 , 20 , 21 , 22 , 23 , 24 ] sound energy, [ 25 , 26 ] and human movement, [ 27 , 28 , 29 ] and has shown its value in marine‐related fields such as ship anti‐corrosion, water purification, and early warning. [ 6 , 30 , 31 ] Over the past few years, with the hard work of more than 50 research groups worldwide, [ 32 , 33 , 34 ] TENG has made rapid advances in output performance [ 17 , 35 , 36 , 37 , 38 ] and device architecture for blue energy harvesting.…”