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First Solar and its cadmium telluride (CdTe) technology dominate thin-film solar in the mainstream market. Valerie Thompson looks at the US-based business and the future of thin-film PV technology.

Practical matters, beyond simply improving on solar cell efficiency, have led the agenda at the European Photovoltaic Solar Energy Conference (EUPVSEC) going on this week in Lisbon. Policy and the geopolitics of solar manufacturing is the big question on everybody’s lips as the event passes its halfway point today. Concerns including grid integration, critical materials consumption, and public acceptance are all being aired frequently – illustrating a closer than ever link between work being done in the labs at solar energy institutes and the everyday lives and energy consumption of people in Europe and around the world.

As efficiency records tumble and devices become more stable, Europe is seeing the beginnings of a race to commercialize high-efficiency perovskite-silicon tandem solar products, reports Valerie Thompson.

German scientists have investigated the role of surface texturing in perovskite-silicon tandem cells and have found that several new processes offer the ability to etch smaller, more uniform textures onto the surface of a silicon cell than today’s industry standard. This could help to ease the subsequent growth of a perovskite cell on top of the silicon, enabling researchers and manufacturers to target higher performance.

Scientists in Germany have discovered a polymer compound that, when added to perovskite thin-film precursor materials, wraps itself around the perovskite crystals, acting as a cushion to protect the perovskite structure from thermomechanical stress. They used the additive to fabricate cells with up to 24.6% efficiency, retaining 96% of their initial performance after accelerated testing equivalent to one year in the field.

Qingdao University researchers have synthesized high-performance titanium dioxide-based anode materials with excellent cycling stability, while German scientists have used operando techniques to observe how solvated sodium ions embed themselves in electrodes.

The US National Renewable Energy Laboratory has demonstrated high-flow-rate hydrogen fueling for heavy-duty vehicles, while France’s TotalEnergies has signed a deal with Adani Enterprises to produce green hydrogen in India.

In other news, Plug Power revealed plans to build a 35-ton-per-day green hydrogen generation plant at Belgium’s Port of Antwerp-Bruges and UK researchers developed an artificial leaf device made from bismuth oxyiodide that is able to harvest sunlight to produce hydrogen fuels.

Scientists in Germany demonstrated a slot die coating process for large-scale production of perovskite thin-film solar cells that achieved a maximum efficiency of 20.83%. Using an additive, and experimenting to find the optimal concentration, the group demonstrated improved control over the crystallization process – crucial for developing stable, repeatable processing.

The Helmholtz Zentrum Berlin set a world record for perovskite-silicon tandem cell efficiency last year at 29.15%. The group has delved further into the cell materials, looking to better understand mechanisms behind the impressive efficiencies achieved so far. Their latest work shows that with the current cell design, long term stability at efficiencies up to 32.4% should be possible.