Spatially confined synthesis of CsPbBr3 quantum dots for high-performance pure-blue light-emitting diodes

All-inorganic CsPbX₃ perovskite quantum dots (PeQDs) offer exceptional optical properties, yet producing bright, stable, pure-blue CsPbBr₃ light-emitting diodes (PeLEDs) remains challenging due to a lack of reliable methods to precisely control the size of PeQDs and induce strong quantum confinement. Here, we report a spatial-confinement approach using metal-organic frameworks to synthesize monodisperse CsPbBr₃ QDs as small as 1.9 nm. Subsequent surface engineering via 3,3-diphenylpropylamine ligand exchange and ionic liquid treated hole transport layers yields pure-blue PeLEDs with a luminance of 2,037 cd m⁻² and an external quantum efficiency of 5.04% at 460 nm. Additionally, we introduce a scalable and solution-processable stamp-mask patterning technique for in situ fabrication of large-scale patterned pure-blue PeLEDs in the emission layer while preserving QD crystallization, nucleation, and film integrity. This simple, rapid, and effective strategy offers valuable reference for the controlled synthesis of ultrasmall PeQDs and the advancement of patterned optoelectronic devices.