The ultimate in power windows

From Cosmos:

Australian researchers say they’ve developed new perovskite solar cells that could effectively and efficiently transform seemingly ordinary windows into active power generators.  The semi-transparent cells let light through, allowing two square metres of glass to be as productive as a standard rooftop panel – yet still be a window – according to a team led by Jacek Jasieniak from the ARC Centre of Excellence in Exciton Science and Monash University.

As such, they suggest in a paper in the journal Nano Energy, they could be something of a game- changer for architecture and urban planning, as well as electricity generation.  Work is now under way investigating how the technology could be built into commercial products, but that is likely to be a decade away.  

The concept is not new, Jasieniak acknowledges, but he says previous designs have fallen short because they were expensive, unstable, inefficient or all three.  He and colleagues report using a different approach based around an organic semi-conductor that can be made into a polymer. When used in place of the common but “unstable” solar cell component known as Spiro-OMeTAD, it produced “astonishing results”.

“Rooftop solar has a conversion efficiency of between 15 and 20%,” Jasieniak says. “The semi-transparent cells have a conversion efficiency of 17%, while still transmitting more than 10% of the incoming light, so they are right in the zone.”

The first application is likely to be large windows in high-rise buildings, the researchers suggest. They are already expensive to make, so the additional cost of incorporating the cells would be marginal.

Architects could have the flexibility to vary the degree of transparency, and with it the generation potential. And they may choose to rethink how they position and angle buildings to optimise solar capture.  Lead author Jae Choul Yu says the next project will look at a tandem device. “We will use perovskite solar cells as the bottom layer and organic solar cells as the top one,” he says.

Semi-transparent perovskite cell