A team of Michigan State University (MSU) researchers has created a transparent solar concentrator able to turn any window (or other sheet of glass, such as the screen for a smartphone) into a photovoltaic solar cell. What makes this development different? The panel is truly transparent.
Earlier attempts at building transparent solar cells resulted in panels with tinted glass and/or compromised visibility. Lead researcher Richard Lunt, an assistant professor of chemical engineering and materials science at MSU, says, “No one wants to sit behind colored glass. It makes for a very colorful environment, like working in a disco.”
MSU researchers used a transparent luminescent solar concentrator (TLSC) that employs organic salts to absorb invisible wavelengths of light, such as ultraviolet and infrared light. “We can tune these materials to pick up just the ultraviolet and the near-infrared wavelengths that then ‘glow’ at another wavelength of sunlight,” Lunt explains. The “glowing” infrared light is then guided to the edges of the panel, where thin strips of photovoltaic solar cells convert it to electricity. “Because the materials do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye,” he adds.
The device “opens a lot of area to deploy solar energy in a nonintrusive way,” Lunt says. “It can be used on tall buildings with lots of windows or any kind of mobile device that demands high aesthetic quality, like a phone or e-reader. Ultimately, we want to make solar harvesting surfaces that you do not even know are there.”
Additional work is needed to improve the TLSC’s energy-producing efficiency. Efficiency in the current version of the solar cells is low — only about 1 percent — but the research team anticipates an eventual increase above 5 percent. Other luminescent concentrators that are not transparent afford efficiency of up to 7 percent.
An article describing the transparent solar cells appeared in the July 2014 edition of the journal Advanced Optical Materials . Other members of the research team include Yimu Zhao, an MSU doctoral student in chemical engineering and materials science; Benjamin Levine, assistant professor of chemistry; and Garrett Meek, a doctoral student in chemistry.
For more Details: See-through solar concentrator harvests energy from sunlight