To make printed solar energy viable researchers have striven to make solar cells convert sunlight and even heat into electricity more efficiently.
A group in the US led by Gregory S. Engel, formerly at the University of California, Berkeley, and now at the University of Chicago seeks to better understand photosynthesis. They cooled a green sulfur bacterium to 77 kelvins (-321 degrees Fahrenheit) and then hit it with ultrashort pulses from a laser, enabling the tracking of the energy flow through the bacterium's photosynthetic system.
The researchers discovered that by using this spectroscopy technique, they could understand how plants efficiently transfer solar energy to molecular reaction centers and then into chemical energy. Photosynthesis had been seen as light harvesting molecules called chromophores absorbing energy from the sun which is then transferred from one such molecule to another along one possible route to reach a reaction center.
The study found that the energy actually moves in a wavelike motion along all pathways in the system at once, a quantum effect that ensures that such energy takes the most efficient route, arriving at its destination almost instantaneously. This new understanding may become the basis for an artificial photosynthesis process that can be incorporated into the design of more efficient printed and thin film photovoltaic cells.