Silk Thin Film-Based Triboelectric Nanogenerators for Energy Harvesting Applications

Triboelectric nanogenerators (TENGs) are efficient, sustainable, low-maintenance, and environment-friendly power sources that are suitable for wireless, portable, and wearable devices. This study, for the first time, presents a vertical contact mode TENG utilizing a thin film of silk and copper film as the triboelectric pair. This contact separation mode TENG is highly flexible, cost-effective, and biocompatible. The silk triboelectric layer is spin-coated on a PET sheet which serves as the flexible substrate of the TENG. The response was maximized by enhancing the surface roughness of the copper film, which in turn increases the contact area during triboelectrification, leading to an increase in charge generation. The optimized TENG yielded a maximum output voltage of 350 $V_{pp}$ and a power density of 4 $W/m^{2}$ and was able to power up commercially available LEDs. Repeatability analysis and TENG performance at different forces yielded satisfactory results.