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Michigan State University researchers say a new transparent solar panel technology is right outside your door. Or more precisely: inside your window. The completely clear innovation could deliver up to 40% of U.S. power.

With the development of a see-through solar concentrator, the MSU scientists believe they have found a way to harvest a massive source of untapped energy. In a Nature Energy report published this week, the university team argues that widespread use of highly transparent solar cells, together with rooftop solar panels, could nearly meet U.S. electricity demands and drastically reduce the use of fossil fuels.

See-through solar-harvesting applications, such as this module pioneered at Michigan State University, have the potential of supplying 40 percent of U.S. electricity demand, according to a new report. (Image Credit: Richard Lunt/Michigan State University)

In 2013, Richard Lunt, professor at Michigan State, and his colleagues created the clear luminescent solar concentrator. When placed on a window, the transparent technology gathers solar energy without disrupting the view.

The thin, plastic-like material can additionally be used on buildings, cell phones, or other devices with a clear surface.

What is a Luminescent Solar Concentrator?

A traditional luminescent solar concentrator, available since the 1970s, is constructed by embedding a piece of plastic or glass with a colorful dye. The colorant absorbs a fraction of the visible solar spectrum and then “glows” at other visible wavelengths.

The glowing light is trapped in the plastic and guided to the edge of the sheet, much like fiber-optics processes, where thin strips of photovoltaic solar cells convert the glow to electricity.

The problem? You may not always want to sit in a room of shining colors.

Although conventional solar panels are made of materials that absorb both the visible spectrum and infrared alike, the MSU concentrator “tunes,” or selectively captures, invisible light while letting the visible light pass right through the solar panel.

Small organic molecules, developed by Lunt and his team, absorb specific, nonvisible sunlight wavelengths. The invisible Infrared light, led to the edge of the plastic, is converted to electricity by thin strips of photovoltaic solar cells.

Because the materials do not absorb or emit light in the visible spectrum, the cell looks exceptionally transparent to the human eye, like a clear piece of glass, according to the Michigan State lead researcher.

“We are actually making the entire system more efficient by allowing visible light through for natural lighting when installed on windows, or a clear view on the front a display,” Lunt told Tech Briefs. “There is no need to use additional real estate just for the solar panel, and so you create these multifunctional surfaces.”

The Future of See-Through Solar

The MSU team has developed two types of transparent solar panels that harvest invisible light; one transports energy electrically, while the other does so with optics. Lunt, the Johansen Crosby Endowed Associate Professor of Chemical Engineering and Materials Science at MSU, believes transparent solar cells will support a variety of new applications.

“We see these devices being deployed anywhere and everywhere: windows, tall buildings, sunroofs, greenhouses, electric automobiles, and mobile electronics,” said Lunt. “They could be all around us without us even knowing, turning our cityscapes into solar arrays.”

By absorbing only invisible light, Lunt imagines the devices providing a similar electricity-generation potential as rooftop solar panels, while improving the efficiency of buildings, automobiles, and mobile electronics.

In the Nature Energy report, the researchers cited an estimated 5 billion to 7 billion square meters of glass surface in the United States. With such a high quantity of glass, the authors believe transparent solar technologies have the potential of supplying approximately 40 percent of energy demand in the U.S. – a figure comparable to the potential rooftop solar units.

“The complementary deployment of both technologies could get us close to 100 percent of our demand if we also improve energy storage,” Lunt said in a recent press release.

In 2011, Lunt co-founded Ubiquitous Energy Inc., a company that aims to commercialize the technologies – an effort that will take time for such a new technology.

“For reference, traditional solar applications have been actively researched for over five decades, yet we have only been working on these highly transparent solar cells for about five years,” Lunt told Tech Briefs. “It typically takes about 10 years for a technology to transition from a lab to commercial products.”

Looking ahead, Lunt and his team will also research how to use the materials to create new kinds of light emitting diodes, medical diagnostics, and solar fuels.

The work is funded by the National Science Foundation and the U.S. Department of Education.

Lunt’s coauthors are Christopher Traverse, a doctoral student in engineering at MSU, and Richa Pandey and Miles Barr with Ubiquitous Energy Inc.

What do you think? How do you see the role of “see-through” solar?

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