A Facile Method and Novel Mechanism Using Microneedle‐Structured PDMS for Triboelectric Generator Applications

The triboelectric generator (TEG) is a cost‐effective, multi‐fabricated, friendly mechanical‐energy‐harvesting device. The traditional TEG, generally formed by two triboelectric materials in multilayers or a simple pattern, generated triboelectricity as it worked in the cycling contact–separation operation. This paper demonstrates a novel, high‐aspect‐ratio, microneedle (MN)‐structured polydimethylsiloxane (PDMS)‐based triboelectric generator (MN‐TEG) by means of a low‐cost, simple fabrication using CO2 laser ablation on the polymethyl methacrylate substrate and a molding process. The MN‐TEG, consisting of an aluminum foil and a microneedle‐structured PDMS (MN‐PDMS) film, generates an output performance with an open‐circuit voltage up to 102.8 V, and a short‐circuit current of 43.1 µA, corresponding to the current density of 1.5 µA cm−2. With introducing MN‐PDMS into the MN‐TEG, a great increase of randomly closed bending–friction–deformation (BFD) behavior of MNs leads to highly enhanced triboelectric performance of the MN‐TEG. The BFD keeps increasingly on in‐contact between MN with Al that results in enhancement of electrical capacitance of PDMS. The effect of aspect ratio and density of MN morphology on the output performance of MN‐PDMS TEG is studied further. The MN‐TEG can rapidly charge electric energy on a 0.1 µF capacitor up to 2.1 V in about 0.56 s. The MN‐TEG source under tapping can light up 53 light‐emitting diodes with different colors, connected in series.