Researchers from Peking University, Eindhoven University of Technology, Chinese Academy of Sciences, Beijing Institute of Technology and University of Science and Technology of China have reported an effective strategy to resolve a long-standing trade-off in blue perovskite light-emitting diodes (PeLEDs), enabling high-efficiency devices through polymerization-driven nanocrystal confinement. Metal halide perovskites are highly attractive for LED applications due to their excellent luminescence p