Solution-processed ZnO energy harvester devices based on flexible substrates

The smart healthcare devices connected to the internet of things (IoT) for medical services can acquire and process physiological data of risk patients, real-time monitoring the patient health. These devices require novel power sources with performance characteristics such as eco-friendly, long lifetime, cost-effective, wearable, and flexible. Conventional electrochemical batteries have various drawbacks, including large volumes, high weight, and toxic components. An alternative technology to gradually substitute the electrochemical batteries is offered by green energy harvester flexible devices. Herein, we propose a simple, low-cost, and low-temperature fabrication process of flexible piezoelectric energy harvesters based on ZnO nanoparticles with the ability to convert green energy from vibration sources into electrical energy. The ZnO nanoparticles are deposited onto ITO (indium-tin-oxide)/PET (polyethylene terephthalate) substrate. The fabricated harvester device has a maximum open-circuit output peak voltage and rms voltage close to 15 mV and 2.5 mV under mechanical vibration of 14 Hz. This fabrication process can allow the development of eco-friendly and low-cost piezoelectric energy harvesters with flexible substrates, lightweight, easy mechanical structure, and no-complex performance.