Researchers from Yale University have identified natural design principles in photosynthesis that could improve energy efficiency in new solar technology.
In photosynthesis, green plants use sunlight to convert carbon dioxide and water into sugars and oxygen. It is a highly complex series of reactions, scientists say — reactions that researchers increasingly try to mimic when creating renewable energy alternatives, such as solar cells that use sunlight to synthesize fuels rather than to produce electricity.
One of the more intriguing features of photosynthesis, scientists say, is how it makes use of visible and infrared solar light. This is accomplished in natural photosynthetic systems by light-harvesting molecular frameworks — photosynthetic antennas — that trigger the quick removal of electrons from water to fix carbon dioxide. But in order for photosynthetic antennas to work smoothly, they need the protection of chemical pigments called carotenoids.
In a new study in the Proceedings of the National Academy of Sciences, researchers from Yale and five other institutions have identified the vibrational fingerprints of pigments responsible for protecting photosynthetic antennas. The study will be published online the week of June 26.
“Our study has revealed a fundamental process for energy transfer,” said Yale chemistry professor Victor Batista, a co-corresponding author of the research. “The same way that paintings get bleached by light, materials for photo conversion also suffer from detrimental processes. Nature has evolved these systems with carotenoids that pick up the excess energy and protect the antennas from decomposition reactions.”
Understanding this process and having a “fingerprint” to identify the specific pigments involved have the potential to help scientists engineer better energy transfer systems in solar technologies, including in crop plant photosynthesis for more sustainable farming.
The idea for the research grew out of discussions at a Telluride summer program for graduate students organized by the Yale Energy Sciences Institute. The principal investigators are Batista and Bruno Robert of the Institute of Biology and Technology Saclay.
Lead authors are former Batista lab members Junming Ho, now a faculty member at UNSW Sydney, and Dalvin Mendez-Hernandez, now a faculty member at the University of Puerto Rico-Cayey, and Elizabeth Kish of the Institute of Biology and Technology Saclay. Additional authors are Katherine WongCarter, Smitha Pillai, Gerdenis Kodis, Devens Gust, Thomas A. Moore, and Ana L. Moore of Arizona State University, and Oleg Poluektov and Jens Niklas of Argonne National Laboratory.
Support for the research came from the European Research Council, the National Research Agency, the French Infrastructure for Integrated Structural biology, the U.S. Department of Energy, the Singapore Agency for Science, Technology and Research, and Yale.
Publication: Junming Ho, et al., “Triplet–triplet energy transfer in artificial and natural photosynthetic antennas,” PNAS, 2017; doi: 10.1073/pnas.1614857114