Polymerization-driven nanocrystal confinement enables 21.8% EQE blue perovskite LEDs

Source Summary

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 properties, but device performance has been constrained by a fundamental contradiction during in situ nanocrystal formation: achieving both high crystallinity and small crystal size. Small nanocrystals are essential for efficient radiative recombination, yet they are typically prone to structural disorder and defect formation, while larger crystals exhibit improved crystallinity but reduced emission efficiency. To address this, the researchers developed an in situ polymerization approach in which polymerizable ligands coordinate with perovskite precursor species during film formation. These ligands subsequently form a polymer network that imposes nanoscale spatial confinement on the growing nanocrystals. This confinement limits crystal growth while maintaining sufficient structural flexibility for lattice reorganization.