Silicon solar cells are reliable work horses which convert solar radiation into electricity with a reasonable efficiency (10 – 20%). The efficiency is limited because 1 photon produces only 1 electron.

In the late 1990’s Arthur Nozik from the National Renewable Energy Laboratory in Golden, Colorado, postulated that in quantum dots, tiny crystals of semiconductors just a few molecules wide, 1 photon could free more than 2 electrons. In 2004, this was experimentally proven with up to 7 electrons being released per photon.

These are promising results for Nozik’s team, who are now trying to compose quantum-dots on a polymer basis into cheap and ultra-efficient solar cells. Theoretically, such a device could have an efficiency of 42%. In practice, a large amount of the freed electrons are too rapidly reabsorbed so that in the laboratory, the efficiency hasn’t yet passed 2%.

That’s something to work on. “If you could do this, you would be standing in Stockholm for the Nobel prize ceremony”, says Nozik.

Arthur Nozik, Photo Technology Review

Read the whole story in MIT Technology Review:

Nanocharging Solar