Transparent and flexible piezoelectric sensor for detecting human movement with a boron nitride nanosheet (BNNS)

For the development and application of wearable electronics, a transparent and flexible piezoelectric sensor (TFPS) system is an important component considering the physical motion energy of the human body. This work newly proposes a transparent and biocompatible boron nitride nanosheet (BNNS) material with a TFPS device. The TFPS device is based on BNNS as a piezoelectric active component and PDMS as a flexible element. The device is able to generate electrical energy from mechanical push force and human movement; it has an output voltage of 22 V, output current of 75 nA, output power of 40 µW (power density: 106 μW/cm3), and energy conversion efficiency of 12.6%. In addition, the TFPS device based on BNNS (1.0 wt%) is proposed as a significant step toward devices which are self-powered by the biomechanical movement of the human foot, neck, wrist, and knee, converted into electric energy in various signal forms. It will be deployed as a body-movement sensor.