Fingerprint-inspired triboelectric nanogenerator with a geometrically asymmetric electrode design for a self-powered dynamic pressure sensor

Effective microstructured active layers in capacitive or resistive-type pressure sensors have been adapted in triboelectric nanogenerator (TENG)-based self-powered pressure sensors to realize battery-free and highly sensitive operations. However, the maximum charge transfer cannot be achieved due to the geometry-driven partial contact status in a microstructured TENG, restricting its application to highly sensitive pressure sensors. In this report, inspired by fingerprint anatomy, a geometrically asymmetric paired-electrode TENG is designed to enhance the pressure-induced electrical output through a microelectrode (μ-electrode) on a microstructured TENG (μ-TENG). The μ-electrode is conformally formed along a 3D dielectric geometry; the shape and density of the μ-electrodes are customized by the finite element method (FEM) and validated experimentally. The optimized μ-electrode design endows higher pressure sensitivity with maximized charge transfer efficiency and exhibits reliable and robust pressure sensing performance. The artery pulse and acoustic pressure (with frequency ranges of 0.1–10 kHz) monitoring capabilities of the μ-TENG can be used for precise healthcare monitoring and discerning a sound signal.