Beyond energy harvesting - multi-functional triboelectric nanosensors on a textile

To accurately evaluate the wellbeing condition of a person, sensing systems with versatile functions are needed. Apart from directly monitoring vital signs, an indirect monitoring approach by measuring human activities with wearable devices has emerged. Herein, a smart textile fabricated with a simple dip coating method is developed with multiple functionalities, such as energy harvesting, physical sensing, and even gas sensing. A maximum output power density of 2 W m(-2) is achieved with a layer of PEDOT: PSS coated textile and PTFE under foot stepping at 2 Hz, and the matched impedance is as low as 14 M Omega. A height-varying multi-arch strain sensor with a large strain sensing range from 10% to 160% is developed. Furthermore, the arch-shaped strain sensors mounted on the human fingers are demonstrated to monitor hand gestures for American Sign Language interpretation and robotic hand control. Additionally, four textile-based sensors located at different body parts are employed to track human activities. Beyond that, the smart textile is also demonstrated to be a building block of a wearable CO2 sensor. Looking forward, this smart textile could be incorporated into real clothes as both energy harvesters and various functional self-powered sensors to enable smart clothes for healthcare monitoring applications.