Effects of surface density of states Ns(E) on the number of effective triboelectric phonons in triboelectric nanogenerators (TENGs): An analytical and numerical study

Abstract

In this work, the concept of triboelectric phonon energy (Eph) is coupled with the triboelectric charge density equation instead of the work function of the metal (WM) to understand electron transfer between a metal and a dielectric. The driving force to initiate electron transfer during a contact-separation process is assumed to be Eph (lattice vibration, heat) because such Eph can kick off electrons from a metallic surface toward a vacuum. These electrons can then be accommodated into the surface density of states Ns(E) on the dielectric surface under the condition that Eph ≥ WM to initiate an electron transfer process. When equilibrium is reached, the number of effective triboelectric phonons (Nphonon) is calculated as a function of Ns(E) along the tunneling distance. As a numerical result, it is found that Nphonon is dependent on Ns(E). © 2019 Elsevier B.V.