By harvesting wave energy, the sensor enables sustainable, long-duration deployment in oceans, rivers and lakes to track water quality trends. Source: National Taiwan University

Researchers in Taiwan have devised a water quality monitoring system that relies on the power of waves rather than batteries to operate. The aluminum gallium nitride/gallium nitride high-electron-mobility transistor (HEMT) sensor is powered by a rotational triboelectric nanogenerator that captures energy from the motion of waves.

The self-powered sensor is encased in a waterproof acrylic shell and operates continuously underwater, detecting concentrations of plastics, heavy metals and other waterborne pollutants. A small capacitor requires only about 10 seconds to charge and enable real-time water quality measurements.

In laboratory and river tests, the HEMT system devised by researchers from National Tsing Hua University, National Taiwan University and Powerchip Semiconductor Manufacturing Corporation demonstrated excellent reliability, distinguishing pollutants down to nanomolar levels and showing a strong linear response to changes in water pH.

"This compact, self-powered device offers a smart solution for remote water quality monitoring and early pollution detection," reported the researchers.

By harvesting wave energy, the sensor described in Nano Energy enables sustainable, long-duration deployment in oceans, rivers and lakes to track water quality trends.