Triboelectric nanogenerators (TENGs) have gained much attention thanks to relatively high output power generation by scavenging various resources such as wind, sound, vibrations, and any physical movement existing in our living environment. In particular, vibration and noise are persistent resources where we can harvest energy. For these resources, most of energy harvesting methods reported to date utilize piezoelectric ceramic materials and harmonic oscillation at the resonant frequency. However, the resonance frequency required for energy harvesting is considerably higher than the level existing in typical factory environment or living environment. Besides, output power level is not sufficient for providing power to electronic devices.
To overcome this limitation in this work, we develop tribeoelectric energy harvesting device that can harvest noise and vibration existing in factory or living environment by designing hybrid device exploiting both piezoelectric and triboelectric generation schemes in a single device structure. Using this approach, the greatly enhanced output power is achieved by dual power generation of hybrid device structure. In the PENG part, electrospun poly (vinylidenefluoride-co-trifluoroethylene) P(VDF-TrFE) nanofiber was sandwiched between Al electrodes as a vibrating membrane. In the TENG part, on the other hand, imprinted micro-pyramid pattern surface was contacted with the PENG’s Al electrode. Thanks to coupling effect between triboelectric charge and piezoelectric charge, greatly enhanced output power was generated, comparable to that of TENG. Under the sound wave of 90 dB at 100 Hz, typical value that exist in factory environment, the integrated output power density of hybrid device exceeded ~3 mW/cm2. The approach introduced here can provide a route to harvest low frequency vibration and sound energy harvesting.
Acknowledgement: This subject is supported by Korea Ministry of Environment(MOE) as Advanced Technology Program for Environmental Industry Program.