12 Aug 2015

Every window… Every screen, a power source?

12 Aug 2015

The background

In 2010 a team of engineers in Massachusetts Institute of Technology’s (MIT) Organic and Nanostructured Electronics laboratory began work on a ground breaking technology that allowed any sheet of glass to become a transparent solar cell.  Richard Lunt, then an MIT post doctorate, suggested that it was possible to create a solar cell that would absorb all the energy from the sun except that part which allows us to see.

How can you create a solar cell that you can see through?

The theory went that as follows; all light is made up of electromagnetic radiation which spans a spectrum of wavelengths.  Each of these contain energy that can be collected by the solar cell, but as good as the human eye is, it can only detect a fraction of the spectrum – visible light.  By developing the cell to only allow that visible light through, the ultraviolet and infrared would be captured and we’d never notice!

Visible light

But it didn’t really work did it?

Well, yes it did.  But unfortunately a major stumbling block was the energy conversion rate, which was very low – around 2% – but at the time the team’s cells transmitted more than 70% of visible light, which is very similar to the tinted windows currently used in many tall buildings.

Is it scalable and can the efficiency rise?

Fast forward to 2015 and the latest transparent glass sheet cells are growing in size.  A detailed theoretical study back in 2013 showed that efficiency should rise to 12% once the glass is in production, a rating similar to current commercial solar panels and during a demonstration two years ago the solar cells powered the LCD display on a small alarm clock.

Already the transmitted light has improved to over 90%, and better production methods have started to increase the efficiencies.

One of the biggest barriers however is longevity.  In a commercial application such as windows, the cells would need to perform for many decades.  The team at Ubiquitous Energy – the company created by the researchers at MIT – believe that in time, with many companies striving to meet the same goals, this issue will be solved and the solar cells will become commercially viable.

Where can I find out more?

Ubiquitous Energy have recently won the 2015 Display Week innovation award for their work into Transparent Photovoltaic Energy products and debuted the Clearview Power™ technology at Display Week 2015, the Society for Information Display International exhibition in San Jose.  Their website can be found here http://ubiquitous.energy/.

If you’re interested in the mechanics behind the technology, MIT’s website has a newsreel dated in 2013 which gives some very technical information. http://mitei.mit.edu/news/transparent-solar-cells

So what does this mean for me?

In time to come, the windows in your home may be able to create enough electricity to run your television, or your fridge.  Offices might be able to harness the power of the sun, enhancing building efficiency in our cities without unsightly solar panels and reducing our reliance on traditional methods of energy production.  Even your smartphone may benefit from solar cells – running out of battery in the middle of that important phone call or web browsing session may just become a thing of the past.

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