Stanford researchers may have found the holy grail on solar cells - the ability to harness light and heat simultaneously in a solar cell.

Using readily available materials, a team of engineers has come up with the first solar technology to combine photovoltaic and thermal electricity generation.

Called “photon enhanced thermionic emission,” or PETE, the process uses cesium to more than double existing systems’ efficiency levels. PETE devices could be easily incorporated into existing solar collection systems, and they’re cheap to boot.

Photovoltaic (PV) cells get less efficient as they get hot, which is one of the biggest problems in solar efficiency. What’s worse, silicon — used in most PV cells — can only absorb energy from certain parts of the light spectrum. Ultimately, more than half the solar energy hitting each cell is wasted.

The Stanford system exploits the excess heat, turning it into extra electricity.

Researchers led by Nick Melosh, an associate professor of materials science and engineering, coated a piece of semiconducting material with a thin layer of cesium. This allowed the cell to use both light and heat to generate electricity, Melosh says.