Solar cells top 40% efficiency

If you haven't been following slashdot, you may not hav heard of a breakthrough in solar cell technology that utilizes a multi-junction configuration to capture light over a range of wavelengths. These cells, developed under U.S. Department of Energy funding, have an efficiency of 40.7%, which is many times that of cells available commercially. This is a huge step towards reliable, renewable energy, though no word on cost or lifetime of these devices yet.