Henrik Lindström and Giovanni Fili

Flexible solar cells for portable devices

Technical field
Electrical machinery, apparatus, energy
Exeger Operations AB
An efficient, affordable and versatile solar cell film developed by Swedish innovators Henrik Lindström and Giovanni Fili is being used to power everyday self-charging electronic devices such as bicycle lights. Lindström, a chemist and technical scientist, and Fili, an entrepreneur, combined their complementary skills to pioneer the production of this innovative printed material and successfully bring their invention to market.

Winners of the European Inventor Award 2021

Solar is one of the fastest-growing energy sources in the world, and recent advances in photovoltaic (PV) technology have been rapid. The third generation of PV technology inlcudes dye-sensitised solar cells (DSSCs), and while these cells tend to be thinner and more flexible than previous generations, commericalisation has been hampered by production costs - particularly the cost of conductive materials.

DSSCs usually consist of a transparent plate topped with a conductive material, indium tin oxide (ITO). Underneath lies a layer of light-sensitive dye that absorbs sunlight and releases electrons. While on a flight, Lindström and Fili were discussing the prohibitve cost of substrates like ITO when they had a breakthrough: why not remove ITO altogether? The inventors immediately mapped out their idea on a paper napkin and began to develop the solution. They shifted the conductive layer behind the absorbing dye layer so that it would not block incoming photons, and then replaced expensive ITO with a conductive layer they developed.Together, the new conductive and dye layers offer a cost-effective, energy-efficient PV film that can power a range of indoor and outdoor products, boosting the commercial viability of the technology.

Powering everyday life

The duo commercialised their patented invention, called  Powerfoyle®, through Exeger Operations AB®. The solar film is highly versatile and can be printed in different colours and manufactured in various shapes or patterns. It was first integrated into bike helmets that use self-charging lights, and several potential uses are currently being researched. These include powering smartphones, e-readers and sensors or installation on surfaces such as  façades, rooftops and windows. 

Exeger currently employs 135 staff and is expanding its operations. It will break ground on an additional factory in 2021, and once complete, the new facility will have the capacity to produce millions of square metres of Powerfoyle per year. CEO Fili, who founded the company in 2008, has a background in business and administration, while Lindström, Exeger's CTO since 2009, holds a PhD in batteries and DSSC solar cell research. By combining their strengths and expertise, the pair have pioneered a new era of affordable, flexible and efficient solar cells.

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