Piezoelectric flexible nanogenerator based on ZnO nanosheet networks for mechanical energy harvesting

Here, we report the simple and flexible nanogenerator based on ZnO nanosheet networks. ZnO nanosheets are synthesized by simple, cost-effective and single-step hydrothermal method on flexible conducting Aluminum substrates at a low growth temperature of 80 degrees C. Nanogenerator is fabricated using ZnO nanosheet networks as an active piezoelectric element with necessary electrodes. Fabricated nanogenerator tested under real-time mechanical forces such as finger tapping, muscle stretching, foot pressure, and mechanical bending. Nanogenerator output was verified by switching polarity and superposition tests and tests confirmed piezoelectric voltage. Fabricated nanogenerators produced open circuit voltage above 100 mV for the single device and 400 mV for four devices connected in series. The simplicity of this method and the reasonable output voltage of the cascaded nanogenerators are useful in practical energy harvesting for future needs.