Technology Review (August 6) -- Stacking different semiconducting materials that collect different frequencies of light—could provide nearly as much of an increase in efficiency as any radical new design. And a new manufacturing technique, developed by MatSE professor John Rogers could soon make this approach practical. Semprius, co-founded by Rogers in 2006, is commercializing ultrahigh efficiency photovoltaic modules, and has sold units that are now in operation at 14 sites around the world.