High power density nanomesh acoustic energy harvester for self-powered systems



Md Osman Goni Nayeem, Haoyang Wang, Chihiro Okutani, Wenqing Wang, Chunya Wang, Sunghoon Lee, Tomoyuki Yokota, Takao Someya



Acoustic energy harvesting presents challenges due to low power density and the lack of efficient devices to convert it to electricity. Here, we developed a nanomesh acoustic energy harvester (NAEH) that harvests sound energy at a peak power density of 8.2 W/m2. The multilayered triboelectric nanomesh harvester with an overall thickness of 50 μm or less generates a high peak-peak open-circuit voltage of 396.9 V and a short-circuit current of 79.9 μA. In addition, a highly aligned polyvinylidene fluoride (PVDF) nanomesh layer generated piezoelectric charges when experiencing strain due to the application of sound pressure waves. The harvested sound energy from different sources at different pressure levels demonstrated the superiority of the NAEH in a wide pressure range. Systematic optimization of charging circuits and powering up a system comprising temperature and humidity sensors and a wireless transmission system with the harvested energy from a 108 dB sound source demonstrated an actual realization of the self-powered system.