Why organic solar cells have low efficiencies

Organic photovoltaics have several advantages over conventional silicon-based cells. Raw materials and manufacturing costs are lower, and they generate less pollution during manufacturing and disposal. But they are significantly less efficient than conventional cells (>3% compared to about 15%). Scientists at the Argonne National Laboratory recently discovered why they lag behind in efficiency: Traces of the catalysts such as palladium used during manufacture “trap” electrical charges the organic cells generate when struck by a photon.

Scientists have known for some time that a similar problem plagues organic light-emitting devices, which work like solar cells in reverse, turning electricity into light. “It’s actually a bit surprising scientists didn’t recognize that this problem could also occur in organic solar cells until recently,” says Seth Darling, an Argonne researcher.

Researchers discovered the trace contaminants by using high-intensity X-rays from the lab’s Advanced Photon Source.

Resources: Argonne National Laboratory