Figure 3.

Wearable biomechanical energy harvesting. (a) Schematic structure and working mechanisms of contact–separation-mode TENGs. (b) Schematic illustration, photograph, output current, and block diagram of a freestanding-mode TENG-powered wearable sweat sensor [33]. (c) Schematics of physiological signal monitoring and structure of a triboelectric all-textile sensor array [67]. (d) Schematic illustration of the flexible hybrid energy harvester that consists of a TENG, an organic PV cell, and flexible electronic circuits [68]. (e) Schematic structure and working mechanisms of PENGs. (f) Photograph, output current, and 1 µF capacitor charging curve of a fabric-based wearable PENG [69]. (i) and (ii) demonstrate its dimensions and bendability, respectively. (g) Schematic structure and shoe insole and watch strap applications of curved multilayer PENG [70]. (h) Self-powered sensor based on nanowire PENGs to monitor finger movement [71].