The triovoltaic effect is a novel energy conversion mechanism that generates direct voltage and current through mechanical friction on semiconductor interfaces. This phenomenon, first proposed in 2019, has led to the development of triboelectric nanogenerators (TVNGs) with various interfaces, including metal-semiconductor, metal-insulator-semiconductor, semiconductor-semiconductor, liquid-solid, and flexible interfaces. Compared to traditional triboelectric nanogenerators (TENGs), TVNGs exhibit higher current density (mA-A cm\(^{-2}\)) and lower impedance (0-kΩ). The tribo-voltaic effect is primarily driven by either built-in electric fields or interface electric fields, with both mechanisms being extensively explored. Additionally, the tribo-photovoltaic and tribo-thermoelectric effects have been discovered, enhancing the multi-physical field interactions. TVNGs are suitable for energy harvesting and self-powered sensing devices, particularly in micro-nano energy applications. This paper reviews the development of the triovoltaic effect, its mechanisms, and potential applications, highlighting the need for further research in mechanism, device fabrication, and integrated applications to advance smart wearable electronics and intelligent industrial components.The triovoltaic effect is a novel energy conversion mechanism that generates direct voltage and current through mechanical friction on semiconductor interfaces. This phenomenon, first proposed in 2019, has led to the development of triboelectric nanogenerators (TVNGs) with various interfaces, including metal-semiconductor, metal-insulator-semiconductor, semiconductor-semiconductor, liquid-solid, and flexible interfaces. Compared to traditional triboelectric nanogenerators (TENGs), TVNGs exhibit higher current density (mA-A cm\(^{-2}\)) and lower impedance (0-kΩ). The tribo-voltaic effect is primarily driven by either built-in electric fields or interface electric fields, with both mechanisms being extensively explored. Additionally, the tribo-photovoltaic and tribo-thermoelectric effects have been discovered, enhancing the multi-physical field interactions. TVNGs are suitable for energy harvesting and self-powered sensing devices, particularly in micro-nano energy applications. This paper reviews the development of the triovoltaic effect, its mechanisms, and potential applications, highlighting the need for further research in mechanism, device fabrication, and integrated applications to advance smart wearable electronics and intelligent industrial components.