A new solar cell material could create windows that produce electricity and help keep your house cool.
The research involved a three-way juggling act. The new material not only had to be transparent like ordinary glass window but also harvest light to make electricity while also blocking it to keep the building cool.
So Hin-Lap Yip of the South China University of Technology and his team used transparent polymer solar cells that allow visible light through but convert near-infrared wavelengths into an electric current. Layers of reflective materials were added to deflect the heat-generating portion of infrared light.
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In tests, the new film transmitted 25 per cent of visible light and converted up to nine per cent of the energy that reached it into electricity. This is lower than the 15 per cent rate typically seen for standard roof mounted solar panels, but the efficiency of polymer solar cells is improving all the time, says Yip.
The researchers calculated that electricity bills could be halved if every window of a house was covered with the panels. Other potential uses are for cars and self-powering greenhouses.
Before these new films can reach the market, Yip says their stability must be improved so they last more than 10 years. He is also exploring the possibility of printing these films to lower the costs.
“Making buildings that harvest light is the future,” says materials expert Mark Miodownik from University College London. But he thinks building industry will need a complete change of mindset before they adopt technology that essentially turns windows into electronic devices.
“The architecture world makes things out of glass, concrete and steel, with a few solar cells tacked on the roof,” he says. “That’s the limit of the integration. A definite shift has to happen in the way people build buildings of the future for this technology to take off.”
Read more: How Tesla’s batteries can change the solar power game
