Solar From All Light | Green Energy News

March 21, 2004 – Vol.8 No.52

SOLAR FROM ALL LIGHT?

The end game, the ultimate goal of solar energy is a technology that yields high efficiency and low cost.

The efficiency of solar cells is related to the technology and materials that they are made of. Now it is understood that the technology that converts the most colors of light - the fullest spectrum - will be the most efficient.

The cost of solar cells is related to those same materials and the manufacturing process needed to make them.

Today the most efficient solar cells are double and triple junction solar cells. These multi-junction cells grab multiple colors of light - multiple energy levels of photons - to employ them in the solar-to-electricity conversion process.

But what if the full spectrum of light - all colors - were put to use?

Scientists at the Lawrence Berkeley Labs have developed a new alloy, zinc manganese tellurium (ZnMnTe) that when incorporating oxygen impurities to make ZnMnOTe, would theoretically convert all energy levels of photons to electricity. The scientists think that a conversion efficiency of 57 percent is possible in a cell described as single-junction and multi-band. Multi-band - meaning multi-bands of light, is new thinking in solar cell technology

But let’s fast-forward, skip over, the technological discussion, of how they work. Let’s cut to the bottom line. Can the new material be mass produced? Can large numbers of solar cells - in the billions - be manufactured cheaply? Has ONE cell been produced?

Scientists remain optimistic, noting that a similar alloy has been produced in Japan. And a Massachusetts Institute of Technology (MIT) scientist has teamed with researchers at LBL to manufacture a cell with the material. Scientists, too, are especially hopeful about the material since many ways to vary the composition of the alloy for the desired result (high solar energy efficiency) seems likely. Visit the LBL NewsBeat at http://enews.lbl.gov/ .