By: Jonathan Benson,
A cohort of scientists from the U.S. and Great Britain have made a breakthrough discovery with regards to solar technology that could revolutionize the way we harvest light for energy. Known as organic solar technology, special cells designed to convert light into energy in the same way that plants do via photosynthesis are set to become a whole lot more efficient as a result of some new tweaks, which means their potential for inexpensive, large-scale use is soon on the horizon.
For years, technologists have been trying to improve the conversion efficiency of solar cells, as all across the board conversion rates have traditionally been low. Typical silicon-based solar cells today, for instance, achieve between 20 and 25 percent energy efficiency, while emerging organic solar cells achieve only about half this amount, or 12 percent efficiency. To make these technologies beneficial on a commercial scale, conversion rates obviously need to be as high as possible.
This is where researchers from the Universities of Cambridge and Washington may have come up with a viable solution. After using a special, laser-based technology to carefully evaluate the way electrons function inside organic solar cells, the multinational team learned some electrons devolve into a catatonic state where they no longer possess energy. Some electrons fall into this “hole,” they found, as a result of variant “spin.”
“‘Spin’ is a property of particles related to their angular momentum, with electrons coming in two flavors, ‘spin-up’ or ‘spin-down,’” explains Science Daily about the findings. “Electrons in solar cells can be lost through a process called ‘recombination,’ where electrons lose their energy — or ‘excitation’ state — and fall back into an empty state known as the ‘hole.’”
Finding: Conversion efficiency can be increased by rewiring electrical current pathways
After pinning down how electrons normally function within an organic solar cell, effectively keeping conversion efficiency rates low, the team figured out that electron spin can be altered to improve these rates. By arranging electrons in a certain way, researchers found that electrons can be prevented from collapsing through recombination, a modality that has the potential to make organic solar technology extremely viable in the near future.
“This discovery is very exciting, as we can now harness spin physics to improve solar cells, something we had previously not thought possible,” says Dr. Akshay Rao, a Research Fellow at the Cavendish Laboratory and Corpus Christi College, Cambridge and one of the lead authors of the study. “We should see new materials and solar cells that make use of this very soon.”
Though “organic” in name, the new technology still requires the use of synthetic, high-performance polymer materials to capture and convert light. But the good news is that the materials needed for the cells can be produced relatively quickly and inexpensively, which will put them more in reach of the general population on an average family budget.
“These materials can be printed like newspaper and manufactured into rolls of film like plastic wrap, so they could have a significant manufacturing cost advantage over traditional materials like silicon,” says David Ginger, a professor of chemistry at the University of Cambridge and co-author of a new study on the technology recently published in the peer-reviewed journal, Nature.
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