Imagine windows that not only provide a clear view and illuminate rooms, but also use sunlight to help power the building they are part of. A group of MIT engineers have developed a new approach to harnessing the sun's energy that could allow just that. Better yet, they hope to have it on the market in three years.

Reported in the July 11 issue of Science, the research involves the creation of a novel “solar concentrator.” Instead of lenses and tracking devices used by most concentrators, this concentrator uses a mixture of dyes painted on the glass (or plastic) to absorb light across a range of wavelengths and then re-emit that energy in a different wavelength and send it across the pane to solar cells at the edges.

“Light is collected over a large area (like a window) and gathered, or concentrated, at the edges,” explains Marc A. Baldo, leader of the work and the Esther and Harold E. Edgerton Career Development Associate Professor of Electrical Engineering at MIT.

The focused light increases the electrical power obtained from each solar cell “by a factor of over 40,” Baldo says. Because the system is simple to manufacture, the team believes that it could be implemented within three years — even added onto existing solar-panel systems to increase their efficiency by 50 percent for minimal additional cost. That, in turn, would substantially reduce the cost of solar electricity.

Three of the graduate researchers who assisted Baldo on the project are starting a company, Covalent Solar, to commercialize the technology.