Triboelectric nanogenerators (TENGs) are widely applied to self-powered devices and force sensors. TENGs consist of the electrode-layer frequently made of high-cost conductors (Ag, Au, ITO) and the tribo-layer of rigid negative-triboelectricity fluoropolymers (PTFE, FEP). The surface morpholoy is studied for enhancing performance. Here, a high-performance Al/PDMS-TENG is proposed with a complex morphology of overlapped deep two-height microneedles (OL-DTH-MN) fabricated by the integrated process of low-cost CO2 laser ablation and PDMS casting for self-powered devices and high-sensitivity force/pressure sensors. The high open-circuit voltage and short-circuit current of the OL-DTH-MN-TENG are 167 V and 129.3 µA. Also, the sensitivity of the force/pressure sensor of the OL-DTH-MN-TENG is very high, 1.03 V N-1 and about 3.11 V kPa-1 , at an area of 30 cm2 that is much higher than the sensitivity of about 0.18-0.414 V N-1 and 0.013-0.29 V kPa-1 of conventional TENG sensors. Meanwhile, the high-performance OL-DTH-MN-TENG not only exhibits the energy storage capability of charging a 0.1 µF capacitor to 2.75 V at 1.19 s, to maximum 3.22 V, but also activates various self-powered devices including lighting colorful 226 LEDs connected in series, the "2020-ME-NCKU" advertising board, a calculator and a temperature sensor. Numerical simulation is also performed to support the experiments.
Keywords: PDMS; energy harvesting; force sensors; pressure; triboelectric nanogenerators.
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