Tapping into sunlight to provide solar energy is generally good for the environment, most people can agree on that. But the technology behind today's solar cells isn't as efficient as you might think. Today's 'Grätzel cells' are the standard for low-cost solar panels and are relatively easy to manufacture. That's all well and good, but the downside is that they don't last all that long. These dye-sensitized cells use an electrolyte made from an organic liquid that has a tendency to leak and corrode the actual solar cell.

With that in mind, researchers from Northwestern University developed a new material for the electrolyte that starts off as a liquid but turns into a solid mass. They claim these solid-state solar cells are much more stable, whereas conventional cells typically last no more than 18 months.

"The Grätzel cell is like having the concept for the light bulb but not having the tungsten wire or carbon material," said Kanatzidis. "We created a robust novel material that makes the Grätzel cell concept work better. Our material is solid, not liquid, so it should not leak or corrode."


The new solar cell uses both n-type and p-type semiconductors along with a monolayer dye molecule that serves as a junction between the two, the researchers explain.

"Our inexpensive solar cell uses nanotechnology to the hilt," said Robert P. H. Chang, a nanotechnology expert. "We have millions and millions of nanoparticles, which gives us a huge effective surface area, and we coat all the particles with light-absorbing dye."

Each solar cell measures a scant half-centimeter by half-centimeter and is about 10 microns thick. Dye-coated nanoparticles are packed, followed by the new material, which is poured in as a liquid and turns into a solid after the solvent evaporates.