Ability of Algae to Switch Quantum Coherence Helps Create Better Organic Solar Cells

First Posted: Jun 18, 2014 06:22 AM EDT

Researchers have successfully identified the strange quantum effect that helps algae survive in very low light.

Researchers at the University of New South Wales, Australia, found that , algae survive in low levels of light by yielding energy from the sun more efficiently through a quantum effect called coherence.

Currently, not much information is available on the function of this quantum effect. But understanding this could further lead to technological advances like better organic solar cells as well as quantum- based electronic devices.

 "We studied tiny single-celled algae called cryptophytes that thrive in the bottom of pools of water, or under thick ice, where very little light reaches them," says senior author, Professor Paul Curmi, of the UNSW School of Physics. "Most cryptophytes have a light-harvesting system where quantum coherence is present. But we have found a class of cryptophytes where it is switched off because of a genetic mutation that alters the shape of a light-harvesting protein. This is a very exciting find. It means we will be able to uncover the role of quantum coherence in photosynthesis by comparing organisms with the two different types of proteins."

In quantum physics, a system that is coherent may exist in several states simultaneously and this effect is called superposition, say the authors.  This phenomenon is basically seen under controlled lab conditions. In this study, the researchers discovered in 2010 that the transfer of energy between molecules in the light harvesting systems from two cryptotype species was coherent. And the same effect was seen in green sulphur bacteria, known to thrive in low light levels.

The researchers assume that this could boost the efficiency of photosynthesis allowing bacteria to thrive in absence of light.

Professor Curmi, "Once a light-harvesting protein has captured sunlight, it needs to get that trapped energy to the reaction centre in the cell as quickly as possible, where the energy is converted into chemical energy for the organism. It was assumed the energy gets to the reaction center in a random fashion, like a drunk staggering home. But quantum coherence would allow the energy to test every possible pathway simultaneously before travelling via the quickest route."

In this study the researchers used X-ray crystallography to view the crystal structure of the light harvesting complexes of three species of cryptophytes. The researchers observed that a genetic mutation in two species led to the insertion of an extra amino acid that altered the structure of the protein complex eventually disrupting the coherence.

This revealed that cryptophytes evolved a powerful genetic switch to regulate coherence as well as alter the mechanism that is used for light harvesting.

The study was documented in the Proceedings of the National Academy of Sciences.

See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone

©2017 ScienceWorldReport.com All rights reserved. Do not reproduce without permission. The window to the world of science news.

Join the Conversation

Real Time Analytics