Synergetic enhancement of the energy harvesting performance in flexible hybrid generator driven by human body using thermoelectric and piezoelectric combine effects

Flexible thermoelectric-piezoelectric generator (f-TPEG) has emerged as the leading candidate to realize long-term biomedical monitoring-based ubiquitous healthcare services. We developed a f-TPEG composed of a piezoelectric (PE) poly(vinylidene fluoride-co-trifluoroethylene) thin film and thermoelectric (TE) bismuth telluride-based alloy blocks. The surficial properties of TE and PE components of f-TPEG were thoroughly optimized to minimize the loss of output performance and enhance the mechanical stability. The f-TPEG harvested a maximum electric voltage of ~17 V and current signals of ~3.8 μA at a temperature difference of 3 K by periodic bendings: The harvested output power of the fabricated hybrid energy generator was well integrated without sacrificing each PE and TE-based energy generation. In addition, to confirm the biological energy harvesting efficiency of the generator, we demonstrated the f-TPEG taped onto human fingers, which converts an output voltage of about 8 V and a current pulse of about 6 μA. The results obtained herein suggest that the f-TPEG would play a variety of important roles in wearable device, which needs long-term biomedical monitoring and applications in smart clothing.