Fig. 2: Critical breakdown electric field for field emission in TENGs.
a Electric field distribution across the gas/vacuum dielectric (Eg) and the film dielectric (ED) in TENGs with the varying gap. The arrow indicates the electric field. b Charge dynamics, and resulting voltage and energy changes. Voltage across the gas/vacuum dielectric (Vg) and the film dielectric (VD) in TENGs with SCD of σD and the transferred charge density of σT; energy density stored in the gas/vacuum dielectric (Ug) and the film dielectric (UD). For the gas/vacuum dielectric layer, its thickness and permittivity are dg and εg, respectively; for the film dielectric layer, its thickness and permittivity are dD and εD, respectively. The arrow indicates the electric potential. c The relationship between critical breakdown voltage and gap distance. d The relationship between critical electric field and gap distance. The solid and dash lines are obtained by the ratio of voltage to gap distance from the modified Paschen curve and the Paschen curve, respectively. e The critical surface charge density of film dielectrics with various thicknesses. f The critical energy density in the gap w/ breakdown. The dash line represents the results described by the Paschen curve. Source data are provided as a Source data file.
