Researchers in Berlin just broke a world record that was barely six weeks old.
Most solar panels use a single layer of silicon to catch sunlight, but silicon has a hard physical ceiling on how much of the light spectrum it can capture. The solution is a tandem cell, stacking two light-absorbing materials so the combination captures more of the spectrum than either could alone. On July 1, teams at Helmholtz Zentrum Berlin and Humboldt University stacked perovskite on top of CIGS, a thin film material made from copper, indium, gallium, and selenium, and hit a certified 25.5 percent efficiency, meaning just over a quarter of the sunlight becomes usable electricity. Europe's official solar test lab verified it, so this is an independently checked result, not a company claim.
It edges out a Tokyo team's record from mid-May of just over 25.1 percent, and the German researchers say their own prototypes have already cleared 27.5 percent internally, though that still needs outside certification. Breaking two records in six weeks is a strong sign of how quickly this field is advancing. The real challenge isn't squeezing another fraction of a percent out in the lab, but turning a fingernail-sized champion cell into a full-sized panel that survives 25 years on a rooftop without degrading.
Still, the science is clearly moving faster than most people realize.
Source: www.pv-magazine.com/2026/07/01/g...