Fully-integrated piezoelectric generators from flexible materials

This paper presents a flexible, integrated piezoelectric system that is simultaneously designed to operate as a self-powered touch sensor and as a charge pump and storage device for the long-term accumulation of energy over several pressure cycles. Rectification is achieved by stacking a piezoresistive polymer on top of a piezoelectric polymer, so that the conductivity of the former switches in phase with the generation of charge in the latter, upon application and release of stress. A thin flexible electrochemical capacitor is then stacked onto the structure to store the generated charge. The resulting integrated generator proves a robust device of general applicability, featuring a flexible and deformable nature, a large dynamic range, and simple manufacturing.