Figure 7.

Performances of the 3L-Gr-TENG with the CTL: (a) CV characteristics of Al/Al₂O₃/3L-Gr/Al at frequencies of 100 kHz and 1 MHz. (b) Surface charge density of graphene (1L, 3L and 5L)-based TENG with and without Al₂O₃ as CTL. (c) Dependence of the output voltage and current outputs as a function of different resistors as external loads. (d) Relationship between electrical output power and external loading resistance. (e) Mechanical stability and durability test of the TENG with the continuous application of ~2000 cycles. The inset shows the output voltage at the initial stage and the final stage after ~2000 cycles. (f) Schematic illustrations showing the charge-trapping mechanism of 3L-Gr-TENG without and with Al₂O₃ charge trapping layer.