New plant pigment may make solar cells more efficient

Researchers from the University of Sydney in Australia have discovered a highly efficient form of chlorophyll that could give solar panels the ability to convert more sunlight into energy. Chlorophyll is what allows plants and other photosynthetic organisms to convert the sun's rays into energy. More than half of the light produced by the sun comes in the infrared range of the light spectrum, and the recently discovered molecule, called chlorophyll f, absorbs light in the infrared part of the spectrum. Previously known types of chlorophyll only absorb light in the visible range from blue to red.

The chlorophyll f was found in ground-up stromatolites, which form in shallow waters and consist of rock and algae. It isn't yet clear which organism created the chlorophyll f, but evidence points to a cyanobacterium. Researchers believe the single-celled, algae-like cyanobacteria adapted to make use of the molecule. The ability to harness infrared light would have given the bacteria a way to survive in an environment in which taller plants and rocks use up or block out much of its visible light.

Prior to this discovery, many researchers doubted that infrared light contained enough energy to split water during photosynthesis and create sought-after oxygen. Currently researchers at the Swiss Federal Institute of Technology are working on low-cost solar cells that absorb light using inorganic molecular dyes in the same fashion as chlorophyll. Tapping into chlorophyll f may help makers of photovoltaic panels find a way to generate electricity using a wider range of light.