Nanograting-assisted flexible Triboelectric Nanogenerator for active human motion detection

This manuscript presents the development of a nanograting assisted Triboelectric Nanogenerator (TENG) for improved performance. The TENG leverages a cost-effective and straightforward fabrication method, utilizing nano-gratings on a Polydimethylsiloxane (PDMS) layer to enhance the triboelectric effect. The device characteristics are evaluated by considering tapping force, separation distance, and load resistance. The experimental electrical characterization shows that the output voltage increases significantly with higher applied forces, with a 2 N force generating voltage increases of over 584% compared to a 0.1 N force. Conversely, the output voltage decreases as the separation distance is reduced. The charge storage capability of the proposed device is demonstrated by integrating a TENG with a full-wave bridge rectifier. Furthermore, the fabricated TENG demonstrates remarkable sensitivity in detecting various body motions. When strategically placed on the biceps, the TENG effectively tracks muscle contraction and expansion with a voltage range of +0.5 V to -1 V, exhibiting a sensitivity of 1.5 V per cycle. Similarly, the TENG accurately detects bending movements in the knee and elbow joints. For knee bending, the voltage output ranges from +2.5 V to -1 V, resulting in a sensitivity of 3.5 V per cycle. Elbow flexion generates voltages between +4 V and -5 V, corresponding to a sensitivity of 9 V per cycle. This clear correlation between voltage and specific body movements makes the TENG a promising candidate for wearable health and motion monitoring systems.