Fossilized Diatoms, an algae that has the ability to manipulate light, are being used to solve a design problem that has long plagued the proliferation of organic solar cells. The diatoms can be found in all waters and in the bark of trees. They possess a skeleton made of nanostructured silica or glass. These small creatures could prove to be important in advancing the design of solar technologies known as organic PV, potentially a lower cost option to the conventional PV technologies. Researchers in a Yale University Laboratory led by Associate Professor of Chemical and Environmental Engineering applied these diatoms to organic solar cells, their results are published in the journal Organic Electronics. “It’s really amazing that these things exist in nature,” said Lyndsey McMillon-Brown, a Ph.D. student in Taylor’s lab, and lead author of the study. “They help trap and scatter light for the algae to photosynthesize, so we’re able to use something directly from nature and put it in a solar cell.” One challenge of designing these devices, though, is that they require very thin active layers, 100 to 300 nanometers, which limits their efficiency in converting light to electricity. The diatoms help because they have been optimized for light absorption through billions of years of adaptive evolution. They are the most common type of phytoplankton found in nature, are cheap and abundant in nature. Collaborators from NASA, Princeton University and Lincoln University who led the project dispersed diatoms throughout the active layer of a solar cell, which ended up reducing the amount of material needed for the active layer to be efficient. “We were able to see what the right concentration was and how much of this material we needed to put into our solar cells to get enhancement,” McMillon-Brown said. “It’s really beneficial because the active layer materials we use are both expensive and very rare.” McMillon-Brown and Taylor said even more can be achieved with a few more minor adjustments. “We can use different species of diatoms and tailor it to the right size, and we can also use some of the better donor-acceptor polymers for a higher performance,” Taylor said. McMillon-Brown said the diatoms seemed like a natural fit for her research as soon as she learned about them. “My work is on biomimicry, so I’m always looking at existing patterns and structures in nature,” she said. “We’re always on the hunt for new patterns in nature because we believe that nature solves all our engineering problems – we just have to find the solutions.”
Researchers from Yale University Laboratory, NASA, Princeton University and Lincoln University have discovered the most common type of phytoplankton can optimise photovoltaic (PV) solar cells. In a report in the journal Organic Electronics, the team revealed how fossilised diatoms, which have evolved over billions of years to optimise light absorption, reduced the amount of rare and costly materials required to make the active layer of a PV cell more efficient.