A high-performance flexible triboelectric nanogenerator based on cellulose acetate nanofibers and micropatterned PDMS films as mechanical energy harvester and self-powered vibrational sensor

Triboelectric nanogenerators are emerging mechanical energy harvesting devices in the era of the Internet of Things (IoT) for powering small-scale electronic devices or functioning as state-of-the-art self-powered sensors. Furthermore, observing vibration patterns from different electronic gadgets helps in assessing the health of the gadgets and also allows to detect the downtime as well as faults pre-emptively. Here, a triboelectric nanogenerator based on electrospun cellulose acetate nanofibers and surface modified PDMS is fabricated for powering commercial sensors. In addition, the effect of surface patterning on PDMS film such as arrays of micropyramid and microdome structures on the output characteristics of TENG has been systematically investigated. The PDMS with micropyramidal arrays in combination with electrospun cellulose acetate nanofibers showed a massive enhancement (~180 times) in the power density of TENG, as compared to the flat PDMS film-based device. The fabricated facile and flexible TENG with micropyramidal surface modification on PDMS can generate an output voltage of 400 V, short circuit current of 3 mA/m2 and peak power density of 0.9 W/m2 respectively. In addition, with a little tweak in the structure, the same cellulose acetate nanofiber-PDMS based TENG is transformed into an active self-powered vibration sensor. Utilizing this, the vibration profile of an electric-sewing machine is mapped under various frequencies of operation. Additionally, anomalous vibrational behaviours from different electronic gadgets such as hard disks and computer fans, as a result of mechanical imbalances, are also detected using the self-powered triboelectric vibrational sensor.