A research team led by Wang Rui from the Future Industry Research Center and College of Engineering at Westlake University, China, developed a flexible perovskite-CIGS tandem solar cell with 23.4% efficiency. Tandem solar cells, unlike single-junction cells, use multiple semiconductor layers to absorb a broader spectrum of sunlight, overcoming efficiency limitations. A related study, published in Nature Photonics on February 3, 2025, introduces a divalent cation replacement strategy to stabilize wide-bandgap perovskite, enhancing efficiency and durability. The newly developed cell is ultra-thin, with a thickness comparable to a human hair, allowing integration on curved and irregular surfaces. Potential applications of these cells include buildings, automobiles, aircraft, and wearable devices, expanding the scope of solar energy solutions.