Researchers at Cambridge University have discovered deep-sea bacteria that convert all light absorbed into electricity, through a process that could be applied to solar photovoltaics.
These green sulfur bacteria live over a mile under the ocean’s surface, where light is scarce.
It is precisely this dark environment that has led the bacteria’s light-harvesting proteins to evolve to use miniscule amounts of light very efficiently for photosynthesis.
Organisms that photosynthesize use a network of pigments held in place by protein structures. These pigment-protein complexes (PPCs) are critical in moving the solar radiation as it undergoes the process of photosynthesis.
Structure of the Fenna–Matthews–Olson pigment–protein complex that is found in green sulphur bacteria. Credit: Daniel Cole, Cambridge University
Researchers at the university’s Cavendish Laboratory discovered a mechanism in this green sulfur bacteria, called the Fenna-Matthews-Olson complex, which doesn’t lose a single photon of energy in the process. This means that green sulfur bacteria are able to move photons through their system without losing energy from the point of absorption.
“Some of the key issues in current solar cell technologies appear to have been elegantly and rigorously solved by the molecular architecture of these PPCs – namely the rapid, lossless transfer of excitons to reaction centers,” said Alex Chin, from Cambridge’s Winton Programme for the Physics of Sustainability.
While standard solar cells having between 15 and 40 percent efficiency, the discovery of the protein that is 100 percent efficient could potentially impact photovoltaic technology, helping to increase standard PV cell efficiency.