Researchers created the first solid-state light-powered nanomotor at the Cockrell School of Engineering at The University of Texas at Austin. Until now, light-driven motors needed to be submerged in an aqueous solution. But the Brownian motion of the liquid molecules pushed the small motors off their spin and made them relatively useless.
To sidestep this problem, the UT team eliminated the water and positioned the nanomotor, which measures 100 nm wide, on a solid substrate where it is powered by laser light. The substrate is coated with a thin film of phase-changing material. The film undergoes a local and reversible change from a solid to a quasi-liquid phase when exposed to light. This phase change reduces the friction created by the nanomotor so it can rotate smoothly.
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Making a nanomotor that does not need to be in solution means it can be placed on a chip and perhaps replace batteries in some cases and then use only light to generate mechanical motion and power. It could be a fuel-free and gear-free engine that turns light into mechanical energy for solid-state micro- or nano-sized devices.
The team plans on making the small motors more stable and controllable, which would let them be more efficient at converting light to mechanical energy.
The researchers envision engineers using the spinning motion of these motors to pick up dust and other small particles to sample and measure air quality. The motors might also be used to distribute drugs inside the human body or to power tiny drones and other small vehicles for surveillance.