‘World-changing’ indoor solar cells offer durable electronics

to mein just six seconds at a factory on the northern outskirts of Stockholm, a top-secret printer spits out sheets worth thousands of euros apiece. Each contains 108 miniature solar cells that will soon find their way into everyday gadgets – from keyboards to headphones – that will fundamentally change the way we interact with technology. According to their creators, they will even force us to rethink our relationship with light.

Sweden may seem an unlikely place for a photovoltaic revolution, but the lack of light during the winter months was one of the reasons Exeger co-founder Giovanni Fili looked beyond the sun as the only source of energy for photovoltaic cells. His company’s breakthrough technology can harvest electricity from virtually any light source, from direct sunlight to candlelight. It can even generate charge from moonlight, although it will take some time before it becomes useful.

“Like algae at the bottom of the ocean, where it is almost dark, we can use very few photons effectively,” says Fili Independent. The T-shirt he wears describes his company’s technology as “world-changing,” capable of simultaneously meeting global energy demand and some of the planet’s greatest environmental challenges.

Indoor solar panels have been used for several decades. Solar-powered calculators were first introduced in the 1970s, but the limitations of the amorphous silicon cells on which they are based mean they are too low power, too fragile and too rigid to be integrated into other products .

The latest innovation stems from a discovery made in 1988 regarding dye-sensitized solar cells (DSSCs). A pair of researchers at the University of California, Berkeley, California, invented a low-cost, high-performance cell that was both semi-flexible and translucent, enabling the commercial development of the technology.

Just over 20 years later, Fili and Exeger co-founder Henrik Lindström developed a new electrode material that provided 1,000 times better conductivity. The breakthrough became the basis for Powerfoyle cells, which are now commercially produced.

Exeger’s Powerfoyle solar cells represent a radical departure from traditional glass-covered panels, eliminating the need for visible silver lines on them to serve as guides. They are also not sensitive to partial shading, which drastically reduces the efficiency of photovoltaic panels.

The patented leather-like material can even transform into almost any material, allowing for seamless integration into a wide range of products while remaining waterproof, dustproof and shockproof.

“It works in all lighting conditions, is more durable than any other solar cell in the world, is easy to produce and can imitate any surface – leather, carbon fiber, wood, brushed steel. This is beautiful too,” says Fili. “So we can integrate with products that already sell billions of units a year.”

The Exeger plant in Stockholm can produce 2.5 million square meters of solar cells per year, making it the largest such plant in Europe. Speaking at the factory opening in 2021, Fili predicted that Exeger’s technology “will touch the lives of one billion people by 2030”

Powerfoyle solar cells have already been used in seven off-the-shelf products – including headphones, wireless speakers and a bicycle helmet – and six more have been announced. Clients include Adidas, Phillips and 3M, although they are also reportedly in talks with LogiTech and Apple.

A future without batteries

Exeger is one of several startups pioneering the commercialization of indoor solar panels, whose promise of clean, unlimited energy is attracting researchers and entrepreneurs alike.

The American company Ambient Photonics was attracted to the space by the “magical” potential of the smart home, as well as the hope that it will be possible to eliminate the need to use disposable batteries.

“The scale at which smart electronics can be implemented is limited by battery life and the use of traditional batteries, which require constant charging, stagnate product design and have negative environmental consequences” – Bates Marshall, co-founder and CEO of Ambient Photonics told Independent.

According to them, TV remote controls alone are responsible for disposing of 3.1 billion disposable batteries every year Samsung estimates. The Korean electronics giant has made switching from alkaline batteries to photovoltaic power a priority to meet sustainability goals, saying it could reduce greenhouse gas emissions by about 6,000 tons per year.

“Every advance in the power density of our product brings us closer to a future where the need for disposable batteries will be significantly reduced, if not completely eliminated,” Marshall says.

Ambient Photonics’ DSSCs have so far been integrated into remote controls, although limitations related to the amount of heat and light they can be exposed to mean the technology is currently limited to indoor applications.

The versatility and durability of Exerger’s Powerfoyle means the only limitations are power-hungry devices such as laptops and smartphones – although they can significantly increase battery life by 50-100%. Exeger is also investigating a solar-powered tablet case that could provide enough power for occasional users to not need to be charged.

“Our grandchildren will laugh that we had cables,” says Fili.

One trend that Fili has noticed is that users of Powerfoyle products have become much more aware of their surroundings and the presence of light in their lives. “We make people aware of the light,” he says, “because light is power.”

Fili believes that Powerfoyle is an era-defining technology. Exeger is the first company to commercialize this technology on such a scale, although it is relatively young considering that Fili views everyone on the planet as a potential user. Others seem confident in his claims, including: Forbes comparing him to figures such as Jeff Bezos, Bill Gates and Elon Musk.

The technology behind Exeger’s solar cells, like the printers that produce them, is a closely guarded secret. Even the purpose of the thousands of Powerfoyles currently printed every minute at the Stockholm factory is not yet widely known. (Their elongated shape clearly suggests that they will be used in a product that most of us use every day – the one on which this article is written.)

“It’s something really, really huge,” Fili says. “We have just signed a contract with the world’s largest keyboard and mouse supplier, and we have already partnered with some of the biggest companies and brands in the world. This technology will take over the world.”