Self-powered, ultrasensitive, flexible tactile sensors based on contact electrification

Tactile/touch sensing is essential in developing human-machine interfacing and electronic skins for areas such as automation, security, and medical care. Here, we report a self-powered triboelectric sensor based on flexible thin-film materials. It relies on contact electrification to generate a voltage signal in response to a physical contact without using an external power supply. Enabled by the unique sensing mechanism and surface modification by polymer-nanowires, the triboelectric sensor shows an exceptional pressure sensitivity of 44 mV/Pa (0.09% Pa^-1) and a maximum touch sensitivity of 1.1 V/Pa (2.3% Pa^-1) in the extremely low-pressure region (<0.15 KPa). Through integration of the sensor with a signal-processing circuit, a complete tactile sensing system is further developed. Diverse applications of the system are demonstrated, explicitly indicating a variety of immediate uses in human-electronics interface, automatic control, surveillance, remote operation, and security systems.