The tribovoltaic effect

Contact electrification (or triboelectrification) (CE) is a universal phenomenon between any two materials or two phases of materials. But a contact between two different materials may results in different output. When a p-type semiconductor sliding on a n-type semiconductor surface, the current flowing between the two electrodes on the top of the p-type and the bottom of the n-type is a direct current. This phenomenon is called tribovoltaic effect discovered in the last few years. The mechanism of the tribovoltaic effect is resulted from the electron-hole pairs generated at the PN junction due to the energy released by the formation of the newly formed chemical bonds at the interface due to mechanical sliding, and the inner field built at the PN junction separates the electrons from the holes, resulting in a DC output. The energy released by forming a chemical bond is called “bindington”, which serves as the exciton for exciting the electron-hole pairs, in analogy to the photovoltaic effect. Here, we first review the recent works on the tribovoltaic effect observed at different interfaces. Then, the mechanism of the tribovoltaic effect is presented. The surface chemical methods for regulating the tribovoltaic effect are discussed. Finally, a technique of hybrid tribovoltaic nanogenerator based on the tribovoltaic effect and its potential applications are elaborated.