Sunflower-like synthetic material that bends towards the light

Sunflowers have the property of bending the stem according to the direction of the sun. This allows you to use limited sunlight to the fullest. A research team from the University of California and Arizona State University has developed a synthetic material called SunBOT (sunflower-like biomimetic omnidirectional tracker), which has the property of chasing light by refracting the stem like a sunflower using nanotechnology.

At first glance, the plant does not seem to move still, but in fact it moves according to environmental changes, such as blooming at the sunrise of the morning sun and closing the flower at sunset or bending the stem in the direction of the sun. Sunflowers have developed to receive a lot of light, and as they are warmed by solar heat, they help pollinate and have a structure that makes it easy to collect bees.

The sun tracking property is useful in solar panels and the like. Solar cells have low power generation efficiency due to a shallow angle of incidence that can most efficiently generate power when receiving light from the front. In fact, when comparing the top-down beam and the beam corresponding to the panel at a 75-degree incidence angle, it is said that the generated effective light energy is damaged by 75% at an incidence angle of 75 degrees.

Scientists have previously developed synthetic materials that distort or bend in response to light intensity and temperature. In essence, however, there has been no synthetic material that can accurately detect and track the direction of stimulation.

The research team focused on materials that react to various light or heat, such as a liquid crystal elastomer containing a hydrogel photosensitive polymer light absorbing dye containing gold nanoparticles. These materials were molded into several millimeters. The synthetic material that looks like a stem, which the research team named SunBOT, senses the heat of light when the laser light hits it, and has the property that one side contracts and the other side expands. Due to this characteristic, the SunBOT is distorted or tilted towards the light.

In fact, as a result of conducting experiments with laser light on SunBOT made of various materials, it is said that it was able to receive light energy up to 400% more efficiently compared to materials that do not respond to light. The SunBOT responds over a wide angle of incidence from 20 to 75 degrees. The research team revealed that the discovery could be applied to solar panels, smart windows, and spacecraft solar navigation radar. Related information can be found here .