Elastic and Skin-Contact Triboelectric Nanogenerators and Their Applicability in Energy Harvesting and Tactile Sensing

Abstract

Skin-actuated self-powered devices based on triboelectric nanogenerators (TENGs) have recently garnered increasing attention, as they can be used to develop electronic skins for healthcare, robotic intelligence, and human interface devices. TENGs typically require tribonegative materials to enable the top layers to either be in contact with or be insulated from other specific materials, resulting in suboptimal performance under practical conditions. Here, we describe the fabrication of a soft, transparent, flexible, stretchable, and skin-actuated TENG device using nanostructured polydimethylsiloxane with a silver nanowire transparent contact as a power source to activate commercial small electronic devices. The nanostructured TENG exhibited a high open-circuit voltage of ∼128 V upon contact with the human skin. This value was substantially higher than that of a TENG with no nanostructure (∼51.6 V), which was attributed to a higher effective contact area in the former. An ∼266 μW/cm2 power density could be achieved with the nanostructured TENG upon finger touch stimulation. The resulting electrical output power was then used to activate small commercial electronic devices such as light-emitting diodes. Additionally, due to its high transparency and signal response, the developed TENG was successfully implemented as a sensory platform to build a 3 × 3 keypad. The TENG devices were affixed to several objects to monitor daily activities and harvest biomechanical energy. Our findings suggest that the skin-stimulated elastomer-based TENG developed herein could open possibilities in the development of wearable sensors and power sources.