Electricity-generating windows? Swiss scientists design more efficient transparent solar panels

All that natural light flowing through your windows may one day do much more than brighten your mood.

Scientists in Switzerland have reached a new efficiency record for transparent solar cells, paving the way for electricity-generating windows that could help power our homes and devices.

Also known as Grätzel cells, dye-sensitised solar cells (DSCs) are a type of low-cost solar cell that use photosensitised dye attached to the surface of a semiconductor to convert visible light into energy.

The previous versions of DSCs were largely reliant on direct sunlight, but scientists at the École Polytechnique Fédérale de Lausanne (EPFL) have found a way to make transparent photosensitisers - molecules that can be activated by light - that can “adsorb” light across the entire visible light spectrum.

“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,” wrote the authors of the study, published in the scientific journal Nature.

DSCs are transparent, flexible and can be manufactured in a wide range of colours for a relatively low cost. These see-through solar panels are already being used in skylights, greenhouses, and glass facades.

In 2012, the SwissTech Convention Center became the first application of DSCs technology in a public building.

In 2017, the Copenhagen International School inaugurated its new building covered by approximately 12,000 blue-hued but transparent solar panels that use the same DSC technology. 

They provide around 300 megawatt hours (MWh) of electricity per year, meeting over half of the school’s annual energy needs.

But despite the