Unlocking nature’s quantum engineering for efficient solar energy

Certain biological systems living in low light environments have unique protein structures for photosynthesis that use quantum dynamics to convert 100% of absorbed light into electrical charge, displaying astonishing efficiency that could lead to new understanding of renewable solar energy, suggests research just published  in the journal Nature Physics.

The research resolves an important mystery in the newly-emerging field of quantum biology – the origins and longevity of the quantum, wave-like properties that transport energy during the early stages of photosynthesis, phenomena unexpectedly observed in molecular complexes extracted from a variety of plants, algae and bacteria.

In photosynthesis, light photons absorbed by pigments such as chlorophyll create excited molecular states, excitons, that carry energy as quantum waves through networks of pigments held in place by protein structures – or pigment-protein complexes (PPCs) – to each PPC’s reaction centre, where the exciton’s energy is used to release electrons needed for photosynthetic chemistry. Preventing the trapping or dissipation of excitons during this journey is a key problem in both nature and man-made solar cells.

Research from Cambridge’s Cavendish Laboratory studying light-harvesting proteins in Green Sulpher Bacteria – which can survive at depths of over 2,000 metres below the surface of the ocean – has found a mechanism in PPCs that helps protect energy from dissipating while travelling through the structure by actually reversing the flow of part of the escaped energy – by reenergising it back to exciton level through molecular vibrations.

Read the full story


Image: Structure of the Fenna-Matthews-Olson complex
Credit: Alex Chin

Reproduced courtesy of the University of Cambridge
_____________________________________________________