Electron transfer in solid-solid triboelectrification

Triboelectrification is a phenomenon that has been observed for over 2600 years, where charges are transferred from the surface of one material to another when they come into contact or rub against each other. However, the mechanism behind triboelectrification has long been debated, with the central issue being the type of charge carrier involved, whether it is electrons, ions, or material residue. Recent research has investigated the fundamental principles underlying triboelectrification at the solid-solid interface through the use of triboelectric nanogenerator (TENG) and Kelvin probe force scanning microscopy (KPFM). The results suggest that electron transfer is the most likely dominant charge carrier in this process, occurring when the electron clouds of two atoms overlap. This paper mainly focuses on the experimental evidence supporting electrons as the main charge carriers in charge transfer and elucidates the newly proposed physical model of triboelectrification.