Key to Organic Solar Cells is Electron Spin: Revolutionizing Renewable Energy

Scientists may have found a way to revolutionize renewable energy. They've created organic solar cells, a new class of solar cell that mimics the natural process of plant photosynthesis. There's only one catch--the cell currently lacks the efficiency to compete with the more costly commercial silicon cells. Now, though, researchers have found a way to improve this efficiency.

Organic solar cells replicate photosynthesis using large, carbon-based molecules to harvest sunlight instead of the inorganic semiconductors used in commercial, silicon-based solar cells. These organic cells can be very thin, light and highly flexible. In addition, the cells can be printed from inks similar to newspapers, which means that their production process if far faster and cheaper than current solar cells.

Unfortunately, there are flaws to these cells. Consistency has been a major issue with some molecules working unexpectedly well while others perform indifferently. In order to find out why this is, the scientists took a closer look at these solar cells.

The researchers developed sensitive laser-based technologies to track the motion and interaction of electrons in these cells. In the end, they found that the performance differences between materials could be attributed to the quantum property of "spin," which is a property of particles related to their angular momentum.

There are two flavors of "spin" for electrons: "spin-up" or "spin-down." Electrons in solar cells, though, can be lost through a process called "recombination." This occurs when electrons lose their energy and fall back into an empty state known as the "hole." In the end, the researchers found that by arranging the electrons spin in a specific way, they could block the energy collapse and increase current from the cell.

"This discovery is very exciting, as we can no harness spin physics to improve solar cells, something we had previously not thought possible," said Akshay Rao, one of the researchers, in a news release. "We should see new materials and solar cells that make use of this very soon."

The findings are crucial for creating better designs for these solar cells. They could, in theory, help revolutionize the way we collect sustainable energy.

The findings are published in the journal Nature.