Researchers from Michigan State University in the US have developed a transparent luminescent solar concentrator that can be placed over windows to creates solar energy, with possible applications for buildings and even consumer electronics like mobile phones.
In the past research into luminescent solar concentrators has been plagued by poor energy conversion rates, as well as materials that have been highly coloured.
“No one wants to sit behind coloured glass,” Richard Lunt, an assistant professor of chemical engineering and materials science at MSU said. “It makes for a very colourful environment, like working in a disco.”
The approach by MSU has made the luminescent layer transparent, by developing a solar harvesting system that uses small organic molecules to absorb only non-visible light.
“We can tune these materials to pick up just the ultraviolet and the near infrared wavelengths that then ‘glow’ at another wavelength in the infrared,” Professor Lunt said.
This infrared light is then guided to the edge of the concentrator module where it is converted to electricity by thin strips of photovoltaic cells.
“Because the materials do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye,” Professor Lunt said.
He said the technology had the potential to be scaled to commercial or industrial applications with an affordable cost.
“It opens a lot of area to deploy solar energy in a non-intrusive way,” Professor Lunt said. “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.”
While the solar conversion efficiency of the module is a paltry one per cent, the team think they could reach around five per cent when fully optimised.