Flexible triboelectric nanogenerator for energy harvesting and pressure sensor

We demonstrate an innovative and effective approach of using the charging process in friction to convert mechanical energy into electric power for driving small electronics. The triboelectric generator (TEG) is fabricated by stacking two polymer sheets made of materials having distinctly different triboelectric characteristics. It relies on the charge pumping effect of the triboelectric potential for driving the flow of electrons in the external load. We have fabricated three types of regular and uniform polymer patterned arrays (line, cube and pyramid) to improve the efficiency of the nanogenerator and make it transparent. Such a flexible polymer TEG gives an output voltage of up to 18 V at a power density of ~0.13 μA/cm2. Furthermore, the as-prepared nanogenerator can be applied as a self-powered pressure sensor for sensing a water droplet (8 mg, ~3.6 Pa in contact pressure) and a falling feather (20 mg, ~0.4 Pa in contact pressure).TEGs have the potential of harvesting energy from human activities, rotating tires, ocean waves, mechanical vibration and more, with great applications in self-powered systems for personal electronics, environmental monitoring, medical science and even large-scale power.