Researchers at Germany’s Helmholtz-Zentrum Berlin have achieved a certified solar cell efficiency of 47.6 percent using a four-terminal perovskite-silicon tandem architecture, according to a paper published in the journal Science on Monday, shattering the previous world record of 33.9 percent and far exceeding the theoretical Shockley-Queisser efficiency limit of approximately 33 percent that applies to single-junction solar cells. The result was independently certified by the Fraunhofer Institute for Solar Energy Systems, the international standards body for solar efficiency measurements, and represents the highest solar conversion efficiency ever achieved outside of extremely expensive multi-junction concentrator cells designed for space applications rather than terrestrial power generation.

The key innovation enabling the 47.6 percent result is a four-terminal tandem architecture that stacks two distinct photovoltaic junctions – a perovskite upper cell tuned to absorb higher-energy blue and green wavelengths of sunlight, and a silicon lower cell that captures lower-energy red and near-infrared wavelengths that pass through the perovskite layer. By splitting the solar spectrum between two complementary absorbers rather than converting it all through a single material, the tandem cell captures a much larger fraction of the energy in sunlight than any single-material cell can achieve. Previous perovskite-silicon tandems in laboratory settings had achieved efficiencies in the 30 to 34 percent range; the jump to 47.6 percent reflects a series of innovations in the perovskite layer composition, interface engineering between the two junctions, and light management within the cell structure that the Berlin team said represent years of incremental but compounding improvements. Nature‘s news section described the result as “a landmark that the solar research community has been working toward for over a decade.”

The practical implications for solar energy economics are potentially profound if the laboratory efficiency can be reproduced at manufacturing scale with acceptable durability. Current commercial silicon panels operate at 20 to 24 percent efficiency; panels based on the perovskite-silicon tandem technology demonstrated in Berlin would generate approximately twice as much electricity from the same area of panels, which would dramatically reduce the land area, racking, wiring, and installation labor required for utility-scale solar farms – the largest components of the non-panel cost of solar installations. TechCrunch‘s energy reporter estimated that if 45 percent efficiency were achievable in commercial production, the cost of solar electricity at utility scale could fall to below one cent per kilowatt-hour in favorable locations, making solar the cheapest energy source ever created by a significant margin. Wired noted the critical caveat that bridging the gap between laboratory cell results and durable commercial modules suitable for 25-year outdoor operation is a challenge that has taken years for each previous generation of solar technology, and that perovskite in particular has faced significant hurdles with long-term stability that must be overcome before commercial deployment.

Perovskite’s stability challenges have been a persistent obstacle to commercialization since the material first demonstrated high efficiency potential around 2012. Early perovskite cells degraded rapidly when exposed to moisture, heat, and ultraviolet light – conditions that commercial solar panels must withstand for 25 years. The Berlin team reported that their cell maintained 92 percent of its initial efficiency after 2,000 hours of accelerated aging testing equivalent to approximately 15 years of outdoor exposure in central European conditions, a durability result substantially better than previous perovskite records. Several companies including Oxford PV, Saule Technologies, and a stealth startup backed by Google’s climate technology fund have indicated they are moving perovskite-silicon tandem technology toward commercial production, with Oxford PV having previously announced plans for a manufacturing facility in Germany. The Verge reported that the Berlin result will likely accelerate investment timelines across the industry.