Algae shells could hold secret to better solar cells

Algae could help us build a cleaner, more sustainable energy future, but not necessarily in the way you might think.

While research continues into ways of converting algae into biofuels, scientists at the Norwegian University of Science and Technology (NTNU) are studying algae for secrets to building better solar cells.

Algae, like land-based plants, convert sunlight and carbon dioxide into energy in the form of sugars and other organic compounds. In fact, algae are by far the most successful organisms in terms of using sunlight … and are far more efficient than even today’s best solar cells, which absorb around 30 percent of incoming sunlight at most.

With that in mind, NTNU researchers are looking into the shell structures of algae, and how these help the organism capture as much sunlight as possible.

Algae build their shells from the inside out as they absorb ions of silicon from seawater. Single-celled diatoms, for example, build shells of symmetrical, complex patterns that are ideal for letting light flow in but not flow out.

By creating models of algae shells using different materials, scientists eventually hope to figure out how to build nanostructures that are optimizing for capturing the sun’s energy.

“In ten years, solar cells will be far different than today, both in design and materials,” said Gabriella Tranell, an NTNU researcher in charge of an interdisciplinary project to study algae’s potential for inspiring new energy technologies. “I think we will be making solar cells that are copies of biological structures. We need to think differently if we want to produce clean renewable energy that is also economic. Solar panels are now designed so that they move smoothly to track the sun as it goes across the sky, from east to west. But maybe we should be looking at the way leaves are arranged on trees: they are not symmetrically oriented towards the light at any time, but are turned in slightly different directions.”

Tranell continued, “We see that it is more and more of interest to imitate nature, to learn how nature has made structures that are functional.”