Realization of enhanced sound-driven CNT-based triboelectric nanogenerator, utilizing sonic array configuration

Triboelectric nanogenerators have been emerged as the most promising mechanical energy harvesters, during last few years. Here, a sonic triboelectric nanogenerator with 7-fold enhanced output power is reported, in which carbon nanotubes are utilized to increase the electrode's effective surface area. To improve the efficiency we have taken advantage of acoustic wave localization in a sonic array. For this purpose, first we have studied an array of periodic acoustic scatterers by simulation. Then, we have designed a 1-D phononic crystal consisting of five steel slabs standing in air medium, which leads to resonance of incident acoustic wave at f = 4.34 kHz. We implemented the design, but replaced the middle scatterer by triboelectric nanogenerator. An enhancement factor of about 4 has been measured for the output voltage of the sonic nanogenerator at f = 4.24 kHz, when it is embedded in the sonic array. Also, power enhancement factor of 7-fold has been achieved (Pout≈4 μW/m2), benefiting from the applied sonic cavity. The measured resonance frequency and enhancement factor are in acceptable agreement with the simulation results. The presented enhanced energy harvesting configuration proposes a compact and low cost structure, which allows parallel energy harvesting, and seems promising for realizing sonic harvesters.