Perovskite - the future of solar panels

The Oxford Solar Research Center (Oxford PV) is about to revolutionize solar panel manufacturing, reports Euronews. Dozens of solar cells are handed out to scientists at the start of the day, who set about experimenting: changing their composition, testing them under pressure in climate chambers and zooming in with microscopes to separate the good cells from the bad.

Their secret ingredient is perovskite, a crystalline structure that increases the efficiency of solar panels when stacked on top of traditional silicon cells.

Currently, Oxford PV, which evolved from an Oxford University research project and has a factory near Berlin, is leading the way in solar cell manufacturing by depositing perovskite on silicon. The center benefits from being a pioneer in perovskite technology, with extensive intellectual property rights and a deal already in place with a US utility company.

Perovskite on silicon: the next big solar breakthrough

No one needs convincing that the future of green technology involves a lot of solar power. In addition to being better for the climate and energy security, solar and wind are now the cheapest ways to add electricity generation in almost any country.

But traditional silicon solar cells face their efficiency limit of about 26% of sunlight converted into electricity.

"We are in another period of turbulence in our industry, whether it is in Europe due to Chinese competition or in the US due to the failure of some of the new thin film PV companies," said Oxford PV CEO David Ward.

Over the past decade, there have been few factors to challenge silicon's title position – mostly the minimal time it takes for a new technological innovation to break through.

In 2020, Oxford PV announced that the efficiency for a perovskite-on-silicon cell starts at 29,5%. According to Ward, there has been significant growth in the new niche since then.

What exactly is perovskite and how does it work?

Perovskite refers to an organic mineral discovered in Russia in the 1800s that was named after the mineralogist Lev Perovsky. It also describes the crystal structure of the mineral, which may contain different atoms.

"Oxford PV's perovskite is produced by machines (which keeps it cheap) and is a semiconductor material suitable for harvesting sunlight," explains Deputy Chief Technology Officer Ed Crossland.

In a typical solar panel, silicon ingots are cut into very thin wafers and spread out to cover the widest possible area. Metal contacts are then added that activate the silicon material. A total of about 60 cells are placed together to form the panel.

For tandem cells, the perovskite is coated on top as an even thinner layer (about 1 micron to 150 microns per wafer), effectively creating two cells in one. Perovskite is invisible to the naked eye, but absorbs a higher energy spectrum from the sun than silicon can absorb.

"By producing more power per panel, perovskite on silicon is the next technological idea that takes solar power beyond what silicon can do on its own," says Crosland.

According to him, silicon has a theoretical efficiency limit of 29%, while the tandem cell can reach 43%.

What can tandem panels be used for?

A range of customers have expressed interest in perovskite solar panels, from homeowners to large utility companies.

In September 2024, Oxford PV shipped its panels to an undisclosed US utility company, in the world's first commercial deployment of perovskite tandem solar technology. The panels are installed in the corner of a new solar field and monitored so US businesses can compare the benefits.

In addition to the main production for solar panels, the Oxford PV factory in Brandenburg can also produce cells for more specialized applications such as aviation.

"Solar panels allow UAVs (unmanned aerial vehicles), which are used for 5G, military surveillance and satellite mapping, to operate as one large flying wing," explains Ward.

With wings limited by weight and size, the power these new solar cells can provide is absolutely strategic.

Perovskite-on-silicon panels could allow UAVs to stay aloft for longer or fly at a more northern latitude where the sun is weaker.