Fast-moving electrons create current in organic solar cells

said braka 11:12 PM
Organic solar cells are built with soft molecules, while

inorganic solar cells, often silicon-based, are built with more rigid materials. Silicon cells currently dominate the industry, but they're expensive and stiff, while organic cells have the potential to be light, flexible and cheap. The drawback is that creating an electric current in organic cells is much more difficult.
To create an electrical current, two particles, one with a  (electron) and one with a positive charge (electron-hole), must separate despite being bound tightly together. These two particles, which together form an exciton, usually require a manmade interface to separate them. The interface draws the electron through an  and leaves the hole behind. Even with the interface in place, the electron and hole are still attracted to each other – there's another mechanism that helps them separate.
"We discovered that this type of electron-hole interface is not one single static state. The electron and the hole can be far apart or close together, and the farther apart they are, the more likely they are to separate," said Libai Huang, an assistant professor of chemistry in Purdue's College of Science, who led the research. "When they're far apart, they're actually very mobile, and they can move pretty fast. We think that this kind of fast motion between the positive and negative charge is what's driving separation at these interfaces."


Read more at: https://phys.org/news/2018-01-fast-moving-electrons-current-solar-cells.html#jCp