Enhanced output in polyvinylidene fluoride nanofibers based triboelectric nanogenerator by using printer ink as nano-fillers

Triboelectric nanogenerators (TENGs) are expected to be new energy supply devices for wearable electronics, which have been proven effective in converting biomechanical energy into electrical energy. Polyvinylidene fluoride (PVDF) is a ferroelectric and piezoelectric material for TENGs, with high crystallinity of which could improve the performance of TENGs. In this work, we have developed TENGs based on PVDF in nanofiber (NF) form, which have high crystallinity. Electro-spinning technique was used to grow PVDF NFs. Commercially available printer ink (PI) nano-fillers were added in PVDF NFs to further increase their crystallinity for enhanced output of PVDF-PI NFs based TENGs. Highest β phase crystallinity of 88%, as quantified by Fourier transform infrared spectroscopy, was obtained for 5 h-grown PVDF-PI NFs, with a TENG performance of 22 W/m², more than double that of PVDF NFs counterpart, which is so far the highest recorded value for PVDF NFs based TENGs. This can be attributed to a competition among ferroelectric domain alignment, surface charge density, and NF medium properties. As printer ink contains magnetic materials, the relation of magnetic properties to the β phase and the power output as a function of growth time have been discussed. We have also demonstrated that PVDF-PI NFs based TENGs can be efficiently used in several potential applications, such as humidity sensors, and easily integrated into flexible electrical and optoelectronic systems, which may open a new avenue in the era of self-powered electronics.