A research team led by Australian scientists says a strange quantum phenomenon during photosynthesis that allows algae to survive in low lights levels might lead to more efficient organic-based solar cells.
The exact function of the quantum effect known as coherence in algae is unknown, they say, but likely is how they harvest energy from the sun at low light levels.
"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 study author Paul Curmi of the University of New South Wales.
While the light-harvesting method of most such types of algae displays quantum coherence, a genetic mutation altering a light-harvesting type of protein in some algae causes it to be switched off, the researchers found.
The finding will allow the study of the role quantum coherence plays in photosynthesis by comparing algae with and without those proteins, Curmi said.
In the often baffling realm of quantum physics, systems deemed to be coherent -- having all their quantum waves moving in step - can exist in different states at the same time, an effect called superposition, the researchers said.
"The assumption is that this could increase the efficiency of photosynthesis, allowing the algae and bacteria to exist on almost no light," Curmi said.
The assumption is that quantum coherence allows energy from captured sunlight to get to the algae's photosynthesis reaction centers as fast as possible, he said.
"It was assumed the energy gets to the reaction [center] in a random fashion, like a drunk staggering home," Curmi said. "But quantum coherence would allow the energy to test every possible pathway simultaneously before travelling via the quickest route."
The researchers said they utilized X-ray crystallography in order to analyze the structure of light-harvesting centers in three species of algae.
All showed the genetic mutation that changed proteins and affected coherence, they said.
"This shows cryptophytes have evolved an elegant but powerful genetic switch to control coherence and change the mechanisms used for light harvesting," Curmi said.
In addition to possible pointing the way to better and more efficient organic solar cells, the finding could lead to a new class of quantum-based electronic devices, the researchers said.
Their next step, the researchers said, would be to analyze and compare different cryptophytes inhabiting different environmental niche to see if the quantum coherence effect is a factor in their survival.
