New type of solar concentrator doesn't block the view

August 19, 2014, Michigan State University

Solar power with a view: MSU doctoral student Yimu Zhao holds up a transparent luminescent solar concentrator module. Credit: Yimu Zhao.
( —A team of researchers at Michigan State University has developed a new type of solar concentrator that when placed over a window creates solar energy while allowing people to actually see through the window.

It is called a transparent luminescent and can be used on buildings, cell phones and any other device that has a flat, clear surface.

And, according to Richard Lunt of MSU's College of Engineering, the key word is "transparent."

Research in the production of energy from solar cells placed around luminescent plastic-like materials is not new. These past efforts, however, have yielded poor results – the energy production was inefficient and the materials were highly colored.

"No one wants to sit behind colored glass," said Lunt, an assistant professor of chemical engineering and materials science. "It makes for a very colorful 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 nonvisible wavelengths of sunlight.

"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," he said.

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

A transparent luminescent solar concentrator waveguide is shown with colorful traditional luminescent solar concentrators in the background. The new LSC can create solar energy but is not visible on windows or other clear surfaces. Photo by G.L. Kohuth.
"Because the do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye," Lunt said.

One of the benefits of this new development is its flexibility. While the technology is at an early stage, it has the potential to be scaled to commercial or industrial applications with an affordable cost.

"It opens a lot of area to deploy in a non-intrusive way," 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."

Yimu Zhao, a doctoral student in chemical engineering and materials science, and Richard Lunt, assistant professor of chemical engineering and materials science, run a test in Lunt’s lab. Lunt and his team have developed a new material that can be placed over windows and create solar energy. Credit: G.L. Kohuth.

Lunt said more work is needed in order to improve its energy-producing efficiency. Currently it is able to produce a solar conversion efficiency close to 1 percent, but noted they aim to reach efficiencies beyond 5 percent when fully optimized. The best colored LSC has an efficiency of around 7 percent.

The research was featured on the cover of a recent issue of the journal Advanced Optical Materials.

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4.5 / 5 (2) Aug 19, 2014
Transparent and inorganic concentrators exist already. 3.8% total efficiency for a 100x100 mm system standing vertically (paper is under review now). Also, this is interesting:
3 / 5 (2) Aug 20, 2014
This transparent and luminescent solar concentrator is a great way to incorporate solar into our homes and businesses. As solar technology and design continues to grow the cost of going solar are also dropping. That's great news for those interested in going solar. They can reduce their monthly electricity costs while gaining annual returns on their investment. You don't even have to live in a sunny area to gain the benefits. Learn more about going solar.
5 / 5 (1) Aug 20, 2014
Cover the display of smart phones, etc., in order to recharge the smart phone, when not I use.
Alternatively, replace the black background of the display with a solar cell.
5 / 5 (1) Aug 21, 2014
This is a great result in organic LSC development. Meanwhile in Australia, inorganic systems are used in conjunction with special coatings for energy savings: https://www.youtu...Y2zrl-w4
not rated yet Aug 21, 2014
"Currently it is able to produce a solar conversion efficiency close to 1 percent", however the article text in Advanced Optical Materials shows (0.4 +/-0.03 %) of conversion efficiency. Whilst this is still a great result, 4 Watts/m2 in a sample of size 7x7 cm is still moderate - but tomorrow or soon thereafter we will all have greater efficiencies. it is important, however, to always pay attention to the difference between what the journalists say for the sake of advertising, and what achievements have actually taken place.
5 / 5 (1) Aug 21, 2014
one more line to convince the audience, finally: https://www.youtu...awUZJqFA
So that everyone knows whose research and development in this area leads the world now...

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