On the material-dependent charge transfer mechanism of the contact electrification

Abstract

Abstract Although contact electrification (CE) has been discovered for more than 2600 years, its dominant charge transfer mechanism by either electrons or materials/ions continues to elude the scientific community. Here, the material-dependent CE mechanism with a model established through the extracted potential barrier height W is demonstrated via the contact-separation mode triboelectric nanogenerator as the tool. The results indicate the W in metal/polymer pairs is mainly determined by the polymer rather than the metal, implying the electron transfer dominant mechanism. On the contrary, the W extracted in CE of polymer/polymer pairs may be related to multiple material surfaces and/or other factors such as chemical reactions, indicating the possible co-existence of both electron transfer and material transfer mechanisms. This material-dependent charge transfer mechanism may give a potential answer to the millennium debate on the CE, which is essential for controlling the surface charge level upon requirements of applications.