We present a single-friction-surface triboelectric generator (STEG). The STEG is transparent and flexible, making possible the use of triboelectric generators in an extended range of applications. This device is fabricated in a simple and very low-cost way. When tapped with a finger, the STEG with micro-patterned PDMS surface achieved an open-circuit voltage over 130 V with a short-circuit current density of about 1 μA cm⁻². A STEG with a flat PET surface is employed as a transparent cover on the screen of a smartphone to generate electric energy from the control motion of the users. The STEG can directly power 3 LEDs when the phone screen is tapped during normal use. In addition, based on the STEG, we have developed a self-powered visualized touch sensor with 4 STEGs serving as the touch pads. The STEG shows promise for applications in systems such as self-powered touch panels and artificial skins.

A self-powered system based on energy harvesting technology can be a potential candidate for solving the problem of supplying power to electronic devices. In this review, we focus on portable and wearable self-powered systems, starting with typical energy harvesting technology, and introduce portable and wearable self-powered systems with sensing functions. In addition, we demonstrate the potential of self-powered systems in actuation functions and the development of self-powered systems toward intelligent functions under the support of information processing and artificial intelligence technologies.