Dielectric layer doping for enhanced triboelectric nanogenerators

As a kind of micro-nano energy collection device, triboelectric nanogenerator (TENG) converts low-frequency mechanical energy into electrical energy, paving the way to micro-nano power sources, self-powered sensors and blue energy. The mechanism of TENG has been incisive explored through vast investigations to enhance their power density and decrease impedance. The external output voltage/current of the TENG results from the opposite charge generated by its electrode layer induced dielectric layer. The addition of doped materials with high dielectric constant enhances the capacitance of the dielectric layer, resulting in an increase in the amount of opposite charge induced by the electrode layer. Consequently, as a method with simple process and high costperformance, dielectric layer doping technology makes it possible to improve the performance and large-scale application of TENG. This review provides a detailed analysis of the impact mechanism of various doped materials (metal, inorganic non-metal, organic polymer and two-dimensional materials) embedded in dielectric layers on TENG output performance, based on TENG and dielectric layer doping theory. Moreover, the extension of dielectric layer doping methods to TENG functionalization or application is also discussed, and the existing and potential dielectric layer doping methods are summarized. Finally, we analyze the emerging challenges and opportunities in dielectric layer doping from multiple perspectives.