A comprehensive review on the mechanism of contact electrification

Contact electrification (CE) is one of the earliest sciences and has a wide range of applications in production sector and life. Some breakthroughs have been made in recent years regarding the mechanism of CE. In this review, we consider different contact interfaces as the entry point, answer some basic scientific questions about CE and explore the material selection, modulation methods, and influencing factors for CE at different interfaces. It is clarified that the dominant mechanism of CE is mainly electron transfer, and the electron transfer process in CE of all contact types is explained by the electron-cloud-potential-well model, which is the fundamental basis for the regulation of CE carried out at different contact interfaces. In addition, we categorize the related research results on the mechanism and modulation means of the tribovoltaic effect related to the CE of semiconductors. Finally, this review describes the opportunities and challenges that the CE field might encounter in the future, with an aim to provide research ideas for related fields.