Cheap nano solar cells

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Janice Boecker, a graduate student at the University of Minnesota, is using nanotechnology to build better solar cells.

Creating electricity is all about moving electrons around and around in a circle. To get this to happen, Boercker harnesses the power of the sun using dye sensitized solar cells.

Little lost electrons

solar cell diagram

a 7500x image of long slender nanowires

Here's how it works: Light shines on the solar cell, exciting electrons in a thin layer of dye on one side of the cell (the cathode). The electrons jump off the dye and move through a conductor, hitting the other side of the solar cell (the anode). If we connect the anode and the cathode, electrons flow from one to the other. That's electricity. If you put, say, a light bulb between the anode and the cathode, it will light up.

But sometimes the electrons get lost in the conductor. Boercker's advisor, Eray Aydil, developed a technique that uses zinc and titanium (ZnO and TiO2) nanowires as conductors. Each of these nanowires is thousands of times thinner than your hairs. But they keep the little electrons on track.

What lies ahead: cheap and efficient

“Longer, thinner, denser--that's our little mantra.”

Boercker working in the lab

If Boercker can grow longer, thinner, and denser clusters of nanowires, the efficiency (or amount of electricity generated by) the solar cells will increase. But she has to keep her eye on the cost of production, since the biggest challenge with solar technology is price.