Serious Solar

Semprius (Durham, NC), a startup company manufacturing tiny concentrated solar cells that forgo any cooling systems has achieved a truly amazing leap in solar cell efficiency. The company was able to hit 33.9 percent efficiency with their solar panel, the first time a commercially-viable solar technology has passed the one-third mark.

Semprius's solar cells use gallium arsenide, rather than silicon, which is able to absorb sunlight and dissipate heat far better. The solar panel that scored this major efficiency record is made up of hundreds of these tiny cells that are about the width of a pen-drawn line. Lenses atop the cells concentrate sunlight 1,000 times.

To capture a better chunk of the solar spectrum, Semprius uses three layers of gallium arsenide, each one tweaked to convert a different part of the spectrum into electricity. Silicon solar cells, by contrast, only absorb a narrow band of sunlight and have efficiency rates that typically fall somewhere in the sub-15 percent area. The record for silicon cell efficiency is 22.9 percent and the previous record for commercial-level solar technology was 32 percent.

Possibly the greatest thing about the Semprius solar panel is that it's not some far distant future technology. It's been designed to be commercially produced and a factory opens this summer to start manufacturing the cells.