Flexible tandem solar cells, promising for lightweight power generation, face a hurdle: getting high-quality layers to stick well to rough surfaces like copper indium gallium selenide (CIGS). Scientists have now developed an innovative strategy to improve this, significantly boosting cell performance and durability. As appeared in Nature Energy on April 18, a team led by Dr. YE Jichun from the Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, used an antisolvent-seeding method to enhance adhesion between the perovskite—a material that efficiently converts sunlight into electricity—top layer and the rough CIGS bottom layer. This approach carefully manages material deposition, ensuring a high-quality interface. Using this method, the team produced a 1.09 cm2 flexible perovskite/CIGS tandem cell with a certified efficiency of 23.8%—one of the highest for flexible thin-film solar cells. The device retained over 90% efficiency after 3,000 bending cycles and 320 hours of operation, showcasing unprecedented durability. This breakthrough accelerates the commercialization of lightweight, high-performance solar cells for portable and wearable applications.
Flexible perovskite/CIGS tandem solar cells developed using the antisolvent-seeding approach. (Graphic: NIMTE)