nanogenerator

A nanogenerator is a nanoscale device that harvests ambient energy and converts it into electrical power. The term was popularized in the field of energy harvesting to describe devices that generate electricity from mechanical or thermal sources through piezoelectric, triboelectric, or pyroelectric effects. Common categories include piezoelectric nanogenerators, triboelectric nanogenerators, and pyroelectric nanogenerators.

Piezoelectric nanogenerators exploit the direct piezoelectric effect: when a piezoelectric material such as ZnO, PZT, or PVDF is deformed, charge separation creates an electric potential. Triboelectric nanogenerators rely on contact electrification and electrostatic induction between materials with different triboelectric properties, producing electricity when contact and sliding motions occur. Pyroelectric nanogenerators harvest energy from temperature fluctuations in materials whose polarization changes with temperature. In practice, many nanogenerators combine these effects or operate in flexible, nanostructured formats.

Materials and structures used include nanoscale forms of zinc oxide, gallium nitride, and other piezoelectrics, as well as polymeric films and composites. Device architectures range from single nanogenerators to arrays and integrated flexible sheets designed for wearables or embedded systems, often paired with power-management circuits and energy storage.

Applications focus on self-powered sensing and low-power electronics. Nanogenerators enable autonomous operation of small sensors, medical implants, environmental monitors, and wearable devices by converting mechanical energy from body movement, vibrations, or ambient heat into usable electrical energy.

Advantages include harvesting energy from ubiquitous ambient sources and enabling self-powered systems, while challenges involve relatively low energy density, durability under real-world conditions, scalable fabrication, and efficient integration with storage and power-management technologies.