This article was published on November 7, 2022

Swiss scientists’ new see-through solar panels are sweet nectar for startups

Europe is opening up solar windows

Swiss scientists’ new see-through solar panels are sweet nectar for startups
Ioanna Lykiardopoulou
Story by

Ioanna Lykiardopoulou

Ioanna is a writer at TNW. She covers the full spectrum of the European tech ecosystem, with a particular interest in startups, sustainabili Ioanna is a writer at TNW. She covers the full spectrum of the European tech ecosystem, with a particular interest in startups, sustainability, green tech, AI, and EU policy. With a background in the humanities, she has a soft spot for social impact-enabling technologies.

As Europe’s transparent solar panel market swells, Swiss scientists have set a new efficiency record for the technology. This could lead the way to energy-generating windows that power up our homes and devices.

Also known as Grätzel cells, dye-sensitised solar cells (DSCs) are a type of low-cost solar cell that use photosensitized dye to convert visible light into electricity.

Previous versions of DSCs have been reliant on direct sunlight, but a team of researchers at the École Polytechnique Fédérale de Lausanne (EPFL) have found a way to make transparent photosensitizers that can absorb light across the entire visible light spectrum, including both direct and ambient. 

The researchers developed a way of improving the combination of two newly designed photosensitizer dye molecules. They did this by creating a technique in which a monolayer of a hydroxamic acid derivative is pre-adsorbed onto the surface of nanocrystalline mesoporous titanium dioxide. 

On top of the new photosensitizers being able to harvest light across the entire visible domain, the scientists have also increased the DSCs’ photovoltaic performance — which has been a weak point of the technology compared to traditional solar cells. 

To put that in numbers, the enhanced DSCs’ efficiency reaches above 15% in direct sunlight and up to 30% in ambient light. For reference, commercial solar panels have an average efficiency between 15% to 22%

In other words, if this technology can hit scale, we may soon see a transparent solar panel revolution in Europe.

How are DSCs already being used?

DSCs aren’t a new technology, but the advances from the École Polytechnique Fédérale de Lausanne could deliver a lifeline to sustainable buildings.

Dye-sensitised solar cells are not only transparent, but can also be fabricated in multiple colors and for low cost. In fact, some are already being used in skylights, greenhouses, as well as glass facades. 

For example, think of the SwissTech Convention Center  — a location that became the first public building to install the DSCs technology in 2012.

The Swiss Convention Center
The Swiss Convention Center. Credit: EPFL

While in 2017, the Copenhagen International School also used the same technology to inaugurate its building with 12,000 colored solar panels, which meet over half of the school’s annual energy needs.

The Copenhagen International School
The Copenhagen International School. Credit: EPFL

And as of 2021, the Netherlands-based company Physee is installing 15,000 of its ‘SmartWindows’ in office buildings across Europe.

Why dye-sensitised solar cells could be a boon to European startups

The scientists at the EPFL have improved this technology’s ability to work in low light conditions, something that’s vital in cloudier, colder countries.

As the authors wrote, “Our findings pave the way for facile access to high performance DSCs and offer promising prospects for applications as power supply and battery replacement for low-power electronic devices that use ambient light as their energy source.”

For European startups, this could be a game changer. While there’s an obvious benefit for installing transparent solar cells on buildings to help meet nations’ net-zero climate goals, the technology’s applicability goes beyond energy-generating windows and glass facades.

DSCs take up far less space than traditional panels, which opens up their use for a wide number of items, whether that’s portable electronic devices (such as earphones and ereaders) or connected sensors that are part of the Internet of Things.

When a scientific advance like this happens, it opens the door for bright minds to create something new and efficient. Let’s just hope Europe’s startups are ready to walk through.

You can find the full research here.

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