Well…it can almost see in the dark. Scientists at the Lawrence Berkeley National Laboratory have just announced that they’ve been able to confirm a new high-efficiency solar cell design that handles pretty much the entire solar spectrum. To ice the solar cake, the new technology can be manufactured using ordinary low-cost processes that are currently in use.
Harnessing the Full Spectrum for Solar Power
A conventional solar cell uses one kind of semiconductor, which captures light from one part of the spectrum. The new solar cell uses different materials, stacked in layers, that respond to different wavelengths. As explained by LBL writer Paul Preuss, the trick is to use one alloy, gallium arsenide nitride, but replace some of the arsenic atoms with nitrogen to create an intermediate energy band. This third band enables the semiconductor to respond to low and mid-energy wavelengths as well as the more “energetic” parts of the spectrum.
Lowering the Cost of Full Spectrum Solar Cells
In earlier trials, the researchers used different alloys that achieved full spectrum responses but involved very high production costs. The advantage of gallium arsenide nitride is that it is very similar to a conventional semiconductor, gallium arsenide, and it can be produced with a commonly used fabrication method involving chemical vapor deposition.
Full Speed Ahead to Full Spectrum Solar Cells
The Lawrence Berkeley breakthrough represents just one path to increasing the efficiency and lowering the cost of solar cells. Over at Ohio State University, a full spectrum solar cell is also under development, and Stanford is pursuing a new technology that cuts around the problem of solar cell efficiency loss due to high temperatures. And then of course there’s low cost solar paints on the horizon, new solar cell fabrication methods, and the use of low-cost materials for concentrating solar power…well, it may be just a bit too soon to say goody-bye to “yesterday’s energy” but we’re sure on our way.
Image: Moon by r w h on flickr.com.