College focuses on powered windows

Chinese scientists have developed a window material made from a thin film of see-through solar cells that could turn windows into miniature electricity generators.

The window-compatible material reported in a study published on July 3 in the journal Joule could potentially double the energy efficiency of an average household.

"Building-integrated photovoltaics are a great example of a market where silicon photovoltaics, despite their cheapness and performance, are not the most appropriate due to their dull appearance and heaviness," said the paper's senior author Yip Hin-Lap, a professor of materials science and engineering at the South China University of Technology.

"Instead, we can make organic photovoltaics into semitransparent, lightweight and colorful films that are perfect for turning windows into electricity generators and heat insulators."

To construct a prototype capable of simultaneously generating electricity while avoiding excessive overheating, the researchers needed to perform a three-way balancing act between harvesting light for electricity generation, blocking it for heat insulation, and transmitting it as a window normally would.

They put together a device that let the familiar visible portions of sunlight through, but reflected infrared light, while at the same time converted near-infrared light rays into an electric current.

In theory, installing windows fitted with dual electricity-generating and heat-insulating properties could cut an average household's reliance on external electric sources by over 50 percent.

While these dual-function materials are still very much in their infancy, the authors expect them to pave the way to create new beneficial technologies.

"Making heat-insulating multifunctional semitransparent polymer solar cells is just the beginning when it comes to exploring new applications for organic photovoltaics," said Yip.

"A version tailored for self-powered greenhouses is only one of many impactful products that we want to develop for the future," said Yip.