Forget putting solar panels on your roof—in the near future, you may be generating electricity from windows, skylights, or even your iPhone.
Researchers at Michigan State University have created a transparent photovoltaic material that can be placed over glass or any other clear surface. It’s not a new idea. Captivated by the notion of transforming glass-walled skyscrapers into giant solar power stations, scientists have spent years tinkering with solar films that can generate electricity.
The problem? Most of those materials carry a colored tint, which would make working in a building with such solar windows “like working in a disco,” in the words of Richard Lunt, an assistant professor of chemical engineering and materials science at Michigan State.
The breakthrough made by researchers led by Lunt was to create a material that is truly see-through. How? The luminescent solar concentrator they developed is composed of organic molecules that absorb wavelengths of sunshine invisible to human eyes, so the device could be made completely transparent. That collected sunlight is then shuttled to the edges of the plastic-like material, where it strikes thin strips of photovoltaic cells to generate electricity.
“The aesthetic quality of this approach is exceptionally high, which is key to many applications,” Lunt wrote in an email.
In other words, the neighbors aren’t going to complain if you install Lunt’s solar concentrators on your picture windows.
They probably wouldn’t even notice. The working prototype that Lunt’s team built looks like an unremarkable piece of clear plastic.
For now, though, the solar concentrator doesn’t produce much power. The prototype was less than 1 percent efficient at converting sunlight into electricity, according to a paper Lunt’s team published in the journal Advanced Optical Materials. Most conventional solar panels like those found on residential rooftops, on the other hand, are around 20 percent efficient.
The goal, Lunt said, is to make the material more than 5 percent efficient. That doesn’t sound like much, but imagine the electricity generated if, say, every window in Los Angeles or Houston was covered with luminescent solar concentrators.
He said it will probably be five or more years before the solar concentrators hit the market. But he and his colleagues have spun off a company called Ubiquitous Energy to commercialize the technology.
Expect to see it first on smartphones and other electronic devices. “It is natural to start with smaller and pricier products and then move toward larger-area applications,” Lunt said.