New perovskite tandem solar cells push past 30% efficiency, even when flexible

Perovskite solar cells have raced up the efficiency charts in recent years, promising cheaper, lighter and even bendable solar power. On May 12, 2026, the Knowridge Science Report described a new milestone from the Ningbo Institute of Materials Technology and Engineering, part of the Chinese Academy of Sciences, published in the journal Nature Nanotechnology: all-perovskite tandem cells that crossed the symbolic 30% mark.

The team reported a certified power conversion efficiency of 30.3% in rigid tandem cells and 28% in flexible versions. They achieved it with what they call a chemical-guided manufacturing strategy, grounded in hard-soft acid-base theory. By adding carefully chosen compounds, difluoro(oxalato)borate for the wide-bandgap layer and tetrafluoroborate for the narrow-bandgap layer, they synchronized how the perovskite crystals form, reducing the tiny defects that normally sap performance and stability. The wide-bandgap subcell improved from 18.5% to 20.1%, and the narrow-bandgap one from 21.6% to 23.3%.

“On May 12, 2026, the Knowridge Science Report described a new milestone from the Ningbo Institute of Materials Technology and Engineering, part of the Chinese Academy of Sciences, published in the journal Nature Nanotechnology: all-perovskite tandem cells that crossed the symbolic 30% mark.”

Durability, long perovskite's Achilles heel, also improved. The rigid cells retained 92% of their efficiency after 1,000 hours of operation, and the flexible cells held 95% of their performance after 10,000 bends. That bendability is what makes the result exciting: flexible, high-efficiency solar could be wrapped onto vehicles, backpacks, rooftops and curved surfaces where rigid panels do not fit, widening where clean power can be generated.

The honest caveats apply. Laboratory cells are typically small, and translating record efficiencies to large, mass-produced modules that survive years of sun, heat and humidity is a major engineering challenge that has tripped up perovskites before. Independent field testing and manufacturing scale-up will be the real proof. Even so, steadily climbing efficiency paired with better stability and flexibility is precisely the trajectory solar needs. If these advances hold up outside the lab, they could help make abundant, low-cost sunlight an even larger share of the world's clean energy.