Tiny Sunflowers That Bend Toward Light and Harvest Solar Energy Created by U.S. Scientists

Scientists in the U.S. have created an artificial sunflower less than 0.04 inches wide that can bend towards a light source and harvest solar energy.

The flowers, dubbed SunBOTs, were found to be about 400 percent more efficient than comparable devices that are stationary, making them a promising technology for solar power—potentially even as a power source for solar-based spaceships.

The team, led by researchers from the University of California, Los Angeles, were looking to improve the efficiency of solar cells by emulating a feature of nature—phototropism. This is where a plant orientates itself to face the sun, optimizing the amount of energy it can get. In a study published in Nature Nanotechnology, the team said achieving tropistic behavior in a synthetic material has been a "daunting challenge."

However, this problem has now been overcome. The team has developed a polymer that is responsive to being simulated by light. The system, which they have named sunflower-like biomimetic omnidirectional tracker—or SunBOT for short—is able to instantly detect and track a light source autonomously. It can do this across a range of temperatures without power supply or any human intervention.

The researchers used the polymer to create a 'stem' that they placed a material commonly used in solar cells on top of, representing the 'flower.' When the team shone a light at the SunBOTs, the polymer began heating up and shrinking, causing the stem to bend so the flower faced the light.

The researchers tested their artificial sunflowers to see how efficient they were at harvesting solar energy. Findings showed they were up to 400 percent more effective than non-phototrophic materials.

The practical applications of SunBOTS are some way off. The study shows a proof of concept, but the technology will need to be scaled up to be used commercially. However, the team is confident it could one day be used across a broad range of industries.

"This work may be useful for enhanced solar harvesters, adaptive signal receivers, smart windows, self-contained robotics, solar sails for spaceships, guided surgery, self-regulating optical devices and intelligent energy generation (for example, solar cells and biofuels), as well as energetic emission detection and tracking with telescopes, radars and hydrophones," the scientific team said.

Sunflowers in Nokesville, Virginia. Researchers in California have created an artificial flower than can harvest solar energy. BRENDAN SMIALOWSKI/AFP via Getty Images