Surface Textured Double Layer Triboelectric Nanogenerator for Autonomous and Ultra-Sensitive Biomedical Sensing

Abstract

Triboelectric nanogenerators (TENGs) have demonstrated great promise especially for the realization of self-powered biomedical sensors. Nevertheless, developing TENG sensors able to detect the broad range of biomechanical movements experienced on the human body is still a challenge. Herein, a unique ridge-structured device sensitive to wide range of forces is reported (i.e., low-forced pulse monitoring to high-forced gait monitoring). The device is composed of thermoplastic polyurethane layer sandwiched between two textured silicon elastomeric layers. Compared to non-textured surface configurations, the proposed ridged-structure provides an increased frictional contact area between the triboelectric materials, while also acting as a spacer between the triboelectric materials. The influence of ridge dimensions on the output performance is investigated by mechanical simulations and electromechanical experimental tests. The optimized device shows a maximum peak output power and current densities of 490 mW m−2 and 1750 µA m−2, respectively at 30 N and 7 Hz of compressive forces. The proposed device exhibits stable electrical output for 10000 cycles. As a proof of concept, the proposed device is used as wearable sensors for monitoring pulse rate, breath patterns, and gait movements. The study suggests the possibility of utilization of novel-structured sandwich-type elastomer ridge-based TENG in different aspects of biomedical sensing and smart wearable application.