A new, compact way to collect sunlight from windows and focus it to generate more electricity could make those multiple expensive rooftop solar panels a thing of the past.

The solar panels that cover the tops of some buildings today contain photovoltaic cells that convert sunlight into electricity. Unlike burning coal, collecting and converting solar energy releases no greenhouse gases, which warm the atmosphere. Limited efficiency and high construction costs have kept solar from producing more than about 0.07 percent of U.S. energy needs in 2007, according to figures from the U.S. Department of Energy.

Solar concentrators can be used to increase the electrical power obtained from the photovoltaic cells. But most concentrators in use today “track the sun to generate high optical intensities, often by using large mobile mirrors that are expensive to deploy and maintain,” said MIT’s Marc A. Baldo, who led the team that created the new type of solar concentrator.

New approach

Instead of covering a large area with solar cells, the new method only requires locating cells around the edges of a flat glass panel.

The MIT solar concentrator involves a mixture of two or more dyes painted onto a pane of glass or plastic. The dyes absorb light across a range of wavelengths, reemit it at a different wavelength and transport it across the pane to the solar cells at the edges.

“Light is collected over a large area [like a window] and gathered, or concentrated, at the edges,” Baldo said.

Focusing the light like this increases the electrical power generated by each solar cell “by a factor of 40,” he added.

The work was funded by the National Science Foundation and the U.S. Department of Energy’s Office of Science.

Read the entire Andrea Thompson article at Live Science.

[An artist's representation shows how a cost effective solar concentrator could help make existing solar panels more efficient. The dye-based luminescent solar concentrator functions without the use of tracking or cooling systems, greatly reducing the overall cost compared to other concentrator technology. Dye molecules coated on glass absorb sunlight, and re-emit it at a different wavelengths. The light is trapped and transported within the glass until it is captured by solar cells at the edge. Some light passes through the concentrator, and is absorbed by lower voltage solar cells underneath. Graphic not to scale. Credit: Nicolle Rager Fuller, NSF]