Light-powered micromotors can move through air

A team of Concordia researchers has developed the first micromotors capable of moving through the air using only light as their power source. These tiny, pollen-shaped particles measure about 12 microns wide—roughly one-tenth the thickness of a human hair. Made of zinc oxide and coated with gold, they use heat from near-infrared light to lift and propel themselves without any fuel or batteries.

When a beam of light strikes the micromotors, the gold absorbs energy and heats the surrounding air. This heat creates gentle convection currents—like rising warm air—that push the particles upward and allow them to move in controlled directions. By adjusting the position of the light, the researchers can steer their motion.

Until now, micromotors could only move in liquid environments, where buoyancy supports their motion. Achieving controlled movement in air is far more difficult because of gravity and the lack of a surrounding fluid. This breakthrough could lead to airborne applications such as microscopic sensors that detect pollutants or particles designed to help clean the air.

The study is published in the journal Advanced Materials.