University of Michigan researchers have found a way to coax electrons to travel much further than was previously thought possible in the materials often used for organic solar cells and other organic semiconductors.
Unlike the inorganic solar cells widely used today, organics can be made of inexpensive, flexible carbon-based materials like plastic. Manufacturers could churn out rolls of them in a variety of colors and configurations, to be laminated unobtrusively into almost any surface.
Organics’ notoriously poor conductivity, however, has slowed research. For years, people had treated the poor conductivity of organics as an unavoidable fact.
The research team showed that a thin layer of fullerene molecules—the curious round carbon molecules also called Buckyballs—can enable electrons to travel up to several centimeters from the point where they’re knocked loose by a photon.
That’s a dramatic increase; in today’s organic cells, electrons can travel only a few hundred nanometers or less. The ability to make electrons move more freely in organic semiconductors could have far-reaching implications.
For example, the surface of today’s organic solar cells must be covered with a conductive electrode that collects electrons at the point where they’re initially generated. But freely moving electrons can be collected far away from their point of origination.
This could enable manufacturers to shrink the conductive electrode into an invisible grid, paving the way for transparent cells that could be used on windows and other surfaces.
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