Self-Powered Dual-Mode Amenity Sensor Based on the Water–Air Triboelectric Nanogenerator

Abstract

A water-air triboelectric nanogenerator (WATENG) is presented for CO₂ sensing application. During the operation of WATENG, two independent charge transfers can be used to characterize the effect of force and humidity, respectively. Thus, the structure of WATENG provides a capability to eliminate these two major interferences in a triboelectric self-powered sensor. With the aid of the polyethylenimine (PEI) coating, WATENG can be used for CO₂ sensing in both static and dynamic conditions. In static condition with a stable CO₂ concentration, the CO₂ sensing is characterized with respect to different relative humidity, and the sensing range can be up to 6000 ppm. In dynamic CO₂ sensing of a pulse gas spray, due to the fast recovery of PEI surface reaction, the sensing range of dynamic situation can be broadened to 30,000 ppm. The self-powered and portable feature of WATENG is preferable as a self-powered amenity sensor for the construction of internet of the things (IoT) sensor networks in the future.