From research at the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB)

Uncovering the cause of power loss in organic solar cells

Although organic solar cells can be manufactured with little energy, they produce only a fraction of the electrical power of crystalline silicon solar cells. Much of the current dissipates into the material.

Image Alexander Schnegg — Dr. Alexander Schnegg mounting samples in the millimetre-wave probe-head of the 263 GHz EPR spectrometer at the Institute for Silicon Photovoltaics at the HZB. Photo/Graphic: HZB.

Image Spectrometer — Photo/Graphic: HZB.

HZB researchers have now shed light on a mechanism involving a link between the electrical current in solar cells and the magnetic moment (spin) of the charge-carrying particles. Using strong magnetic fields and microwaves, researchers led by Dr. Alexander Schnegg and Dr. Klaus Lips managed to “turn” the spin of the charge-carriers. Measurements showed that the current is blocked when the spins are arranged parallel to each other, but flow freely when the tiny magnets are aligned opposite each other. Thanks to this important discovery, researchers can now improve organic solar cells – e.g., through the development of new plastics with special spin properties.

Franziska Rott/red.

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