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Perovskite breakthrough could brighten solar industry

Perovskite has great industry potential as a much cheaper, more flexible alternative to conventional silicon-based solar cells. But researchers haven’t been able to produce a perovskite version that’s durable enough to withstand the sun’s rays over time – until now.

Researchers led by Michael Grätzel at the Swiss Federal Institute of Technology in Lausanne (EPFL) have found a way to produce perovskite solar cells (PSCs) that combine high efficiency with stability, paving the commercial way for a cheaper alternative to silicon-based photovoltaic technologies. The innovation has been published in the journal Science.

According to an EPFL press release, the new method yields PSCs that are stable enough to retain more than 95% of their original sunlight-to-electricity conversion efficiency (over 20%), even when exposed to full sunlight at temperatures of 60 degrees Celsius (140 degrees Fahrenheit) for over 1,000 hours.

These properties could help bring PSCs past the point of promising laboratory prototype and towards industry readiness.

“This is a major breakthrough in perovskite solar cell research and will pave the way for large-scale commercial deployment of this very promising new photovoltaic technology,” said Grätzel, head of the EPFL Laboratory of Photonics and Interfaces, in a statement on Thursday.

Pushing past a solar plateau

Today, most photovoltaic devices on the market – including the solar panels you see on the roofs of buildings – are made from a network of crystalline silicon wafers, which absorb the sun’s energy and convert it to electricity. But these “first-generation” solar cells suffer from drawbacks that have caused them to hit a development plateau: they’re heavy and rigid, as well as expensive to produce.

Perovskite is a mineral that has been of great interest to the solar industry for several years for its potential to offer a more lightweight, flexible alternative to silicon solar cells at a comparable level of efficiency.

But the major advantage of PSCs is that they are significantly cheaper to manufacture. Until now, the biggest hurdle to marketing perovskite-based photovoltaic technologies has been designing a PSC that is stable enough to withstand the sun’s glare over long periods of time.

EPFL’s new technique involves depositing very thin layers of a polymer called cuprous thyocianate (CuCSN) and a layer of gold onto a perovskite film, with a thin layer of another compound called reduced graphene oxide in between. Together, these structures help lend the solar cell greater strength and durability without compromising efficiency.