Synthetic sunflowers may hold key to improved solar energy collection


Dylan Wu

Researchers have recently reported on an innovation that may make solar energy panels more efficient in capturing the sun’s rays, and this innovation represents the latest example of nature inspiring technology. 

We all have seen solar panels on rooftops or along expansive fields aligned in perfect unison towards the sky.  While these panels are generally directed southwards in the northern hemisphere (and northwards in the southern hemisphere) to best capture the sun’s energy, they are still generally inefficient because of the sun’s ever-changing track across the sky and the resulting changes in the angles of the sun’s rays incident to the solar panels.

Now, researchers at UCLA have developed the first artificial phototropic material to mimic perhaps one of nature’s best solar energy collectors: sunflowers, which are famously known for naturally tracking the position of the sun to best absorb its energy for pollen germination and seed production.  Dubbed SunBOTs (Sunflower-like Biomimetic Omnidirectional Tracker), these solar energy panels are mounted on a “stem” made of reversibly photoresponsive materials, including elastomers and hydrogels. And the idea is remarkably simple: as the thermal energy of the sun heats a particular side of the stem, the man-made material shrinks and therefore causes the stem and the solar panel to bend towards the direction of the sun.  When the SunBOT has bent enough, the side of the stem is no longer heated and stops shrinking, thereby fixing the solar panel in perfect position. This process of reversible heating and cooling continues as the sun continues its path during the day, and scientists believe that it can result in the solar panels capturing many more times the energy of a standard fixed panel.

As reported in Nature Nanotechnology this month, the scientists hope that this elegant and energy-efficient design will pave the way towards self-sustaining, autonomous, and intelligent energy generation.