Photosynthesis Map May Hold Clue to Improving Solar Cell Efficiency

The results of measuring the flow of energy during photosynthesis using spectroscopy could contribute to the development of more efficient solar energy technologies.

Researchers at Lund University used ultrafast 2D electronic spectroscopy to track the excitation-energy flow through the entire photosynthetic system of green sulfur bacteria. They located the routes along which solar energy was transported, mapped the functional organization of individual complexes within the photosynthetic unit and demonstrated that energy was transferred within subunits within a period of subpicoseconds to a few picoseconds. They additionally demonstrated that across cell components, energy was transferred within a much lengthier timeframe of tens of picoseconds.

Scientists have been able to locate the routes along which solar energy is transported during the photosynthesis using ultrafast spectroscopy. Courtesy of Marcelo Alcocer.

The measurements revealed that the transport of solar energy was more efficient within subunits than between different components of a cell and that bottlenecks in the energy transport route between components affected the efficiency of the entire photosynthetic energy conversion process.

For about 80 years, researchers have known that photochemical reactions inside an organism do not occur in the same place as where it absorbs sunlight. What has not been known, however, is how and along what routes the solar energy is transported into the photosynthetic organism

Additional studies of how energy is transported in both natural and artificial systems are required before the results of the research can be applied to industry.

Scientists have been able to locate the routes along which solar energy is transported during the photosynthesis using ultrafast spectroscopy. Courtesy of Marcelo Alcocer.

"However, in the longer term, our results might well provide the basis for the development and manufacturing of systems on a molecular level that collect, store and transport sunlight to the solar cells," said professor Donatas Zigmantas. “Not even the best solar cells that we as humans are capable of producing can be compared to what nature performs in the first stages of energy conversion,” he said. “That is why new knowledge about photosynthesis will become useful for the development of future solar technologies.”

The research was published in Nature Chemistry (doi: 10.1038/nchem.2525).