Piezoelectric Energy Harvesting Devices: An Alternative Energy Source for Wireless Sensors

Table 10

Summary of some promising and demonstrated capabilities of nanogenerators (NGs).

Demonstrated capabilities of nanogenerators	Reference
(1) Flexible high output nanogenerator based on lateral ZnO array successfully lights a commercial LED	[31]
(2) A vertically integrated ZnO-based nanowire generator successfully powered pH and UV nanosensors, a self-powered nanowire system	[80]
(3) A high output nanogenerator managed to drive a small liquid crystal display (LCD), indicating a possibility of driving flexible displays	[81]
(4) Air/liquid-pressure and heartbeat-driven flexible fiber nanogenerators as a micro/nano-power source or diagnostic sensor have been successfully demonstrated	[82]
(5) Self-powered system with wireless data transmission—a system composed of integration of an NG, power conditioning electronics, sensor, and RF data transmitter. Wireless signals sent out by the system were detected by a commercial radio at a distance of 5–10 m. This opens potential application in wireless biosensing, environmental/infrastructure monitoring, sensor networks	[83]
(6) Self-powered environmental sensor system driven by nanogenerators, such a system is made of a ZnO nanowire-based nanogenerator, a rectification circuit, a capacitor for charge storage, a signal transmission LED light, and a carbon nanotube-based Hg^2+ ion sensor. It is the first demonstration of a nanomaterial-based, self-powered sensor system for detecting a toxic pollutant	[84]
(7) Replacing a battery by a nanogenerator with 20 V output managed to drive a commercial buck convertor board, and a regulated voltage of 1.8 V with constant current load was achieved to drive an electrical watch for more than 1 minute after the board was charged by the NG with 1000 cycles of deformation. This is the first time that an NG works as a battery part for real commercial consumer electronics.	[85]