A new solar record: this tandem cell now turns 35.5% of sunlight into power

For decades, a hard physical ceiling has shadowed solar power. A single-junction silicon cell can theoretically convert only about 33.7% of the sunlight that strikes it into electricity — the so-called Shockley-Queisser limit. On July 14, 2026, the Chinese manufacturer LONGi announced it had pushed comfortably past that barrier, reporting a crystalline silicon-perovskite tandem solar cell with a conversion efficiency of 35.5%.

The result was certified by the European Solar Test Installation (ESTI), an independent laboratory whose measurements are trusted across the industry. The number is not a one-off spike but the latest step in a steady climb: LONGi's Central Research Institute moved from 34.85% to 35.2% and now to 35.5%. As the company put it, the series of advances "clearly demonstrating the R&D strength and spirit of exploration at LONGi's Central Research Institute."

“A single-junction silicon cell can theoretically convert only about 33.”

The trick behind tandem cells is elegant. A thin layer of perovskite — a crystal material that is cheap to produce and absorbs the bluer, higher-energy part of sunlight — is stacked on top of a conventional silicon cell, which harvests the redder wavelengths. Together they capture far more of the solar spectrum than silicon alone. This architecture has a theoretical ceiling near 43%, so there is still substantial room to grow, and every fraction of a percent means more electricity from the same rooftop or the same patch of desert.

Why it matters is simple: higher efficiency lowers the cost of clean energy. When a panel produces more power from the same surface area, developers need less land, less material and less mounting hardware for every kilowatt-hour. Record-setting laboratory cells still have to be translated into mass-produced modules that survive decades of sun, heat and rain, and perovskite stability remains an active engineering challenge. But the direction of travel is unmistakable. Each new record chips away at the price of solar electricity, and a world that can harvest sunlight more efficiently is a world with cleaner air and a steadier path away from fossil fuels.