Baldo has coated the surfaces of 10 cm square pieces of glass with dyes that glow orange under an ultraviolet lamp. However, the uncoated edges of the glass are shining more brightly than the top.

The sheet of glass is called a solar concentrator. This is the device that gathers normal, natural diffuse light and focuses it onto a small solar cell. Solar cells are multilayered electronic devices made of highly refined silicon and are very expensive to manufacture. The bigger they are, the more they cost. Solar concentrators can lower the overall cost of solar power by making the cells much smaller. Usually, though, the concentrators are typically made of curved mirrors or lenses which are bulky and need elaborate mechanical systems to help them track the sun.

These glass sheets are different as they act more as waveguides by channeling the light in the same way that fiber-optic cables transmit optical signals. The dyes in this experiment that coat the surfaces of the glass absorb sunlight. Different dyes are used to store different wavelengths of light. Then the dyes will re-insert the light into the glass and the glass channels it to the edges. Solar cell strips have been attached to the edges and accept the light and generate electricity. The larger the surface of the glass compared with the thickness of the edges, the more the light is concentrated and the less the power costs.

Baldo, an associate professor of electrical engineering, published his findings recently in Science. He believes that his solar concentrators can be made large enough for the electricity they generate to compete with electricity from traditional sources, such as fossil fuels. He believes that this could be the cheapest solar technology available.

The process for making these solar concentrators begins in another lab at MIT. Several bottles filled with colorful dye powders are measured carefully into small vials. Some of the dyes had been developed for use in car paint; others have been used in creating organic light emitting diodes. Both types of guys are very hardy and can last for years in the sun. This, of course, is essential for solar panel devices.

Once he has measured out the powders, a solvent is added to each to make a form of liquid ink.

Next, the ingredients are placed inside a sealed box and each solution is mixed. It is critical that the right combination of inks is used. If the glass sheet is coated with a dye that absorbs sunlight in those green range of the solar spectrum and emits light that is in the same wavelength, emitted light will in turn be reabsorbed by the dye and it will never reach the edge of the glass.

After the mixture is formed, a small amount is poured on the glass structure. Within a minute or two, the solvent has evaporated out of the dye in the process is finished. The solar panel concentrator with its new coating of orange dye is complete.