CLEARLY THE WAY TO GO

Researchers at Michigan State University have developed a new type of transparent solar panel that can be placed over a window to harvest the energy of the sun.

The breakthrough technology could lead to the creation of buildings that are completely energy self-sufficient, as well as mobile phones that could be left in the sun to charge themselves.

Previous attempts to produce energy from solar cells placed around luminescent plastic-like materials have produced poor results. The materials were highly coloured and the energy production was inefficient.

Richard Lunt, of MSU’s College of Engineering, said: “No one wants to sit behind coloured glass. It makes for a very colourful environment, like working in a disco. We take an approach where we actually make the luminescent active layer itself transparent.”

The solar harvesting system uses small organic molecules developed by Lunt and his team to absorb specific non-visible wavelengths of sunlight.

He added: “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.”

The ‘glowing’ infrared light is guided to the edge of the plastic where it is converted to electricity by thin strips of photovoltaic solar cells.

Lunt said: “Because the materials do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye.

“The technology opens a lot of opportunities to deploy solar energy in a non-intrusive way... ultimately we want to make solar harvesting surfaces that you do not even know are there.”