CsPbBr3@MIL-53 Nanocomposite Phosphors:Synthesis,Properties and Applications in White LEDs
The all-inorganic CsPbX3(X=Cl,Br,I)perovskite nanocrystals have been widely applied in optoelectronic devices due to their excellent optoelectronic properties.However,their poor stability remains one of the main factors restricting their commercial development.This research focuses on improving the stability and solid-state luminescence performance of CsPbBr3 nanocrystals.The porous MIL-53(Al)metal-organic frameworks(MOFs)with outstanding hydrophobic properties was chosen as the encapsulation matrix.CsPbBr3 nanocrystals were grown in situ within the MIL-53(Al)channels by using a thermal injection process to successfully synthesize CsPbBr3@MIL-53 nanocomposite phosphors with outstanding solid-state luminescence performance and high stability.MIL-53 chelates with CsPbBr3 nanocrystals through benzene rings and organic ligands,firmly anchoring nanocrystals in the pores.This not only protects the CsPbBr3 nanocrystals from external environmental influences but also effectively prevents aggregation between nanocrystals,thereby avoiding quenching of solid-state fluorescence.Additionally,the COO functional groups in MIL-53 bind with the unpaired Pb2+on the surface of CsPbBr3 nanocrystals,passivating the surface defects and suppressing non-radiative carrier recombination.Furthermore,the contained benzene rings and organic long chains endow the nanocomposite phosphors with excellent hydrophobic properties.The synergistic effect of these factors significantly enhances the optical performance and water stability of CsPbBr3@MIL-53 nanocomposite phosphors.As a result,photoluminescence quantum yield(PLQY)of CsPbBr3@MIL-53 nanocomposite phosphors reaches 75.4％,which is 2.3 times of that of solid-state CsPbBr3 nanocrystal powders(33.2％).Even after being completely immersed in water for 10 h,its fluorescence intensity can still maintain 75.6％of the initial value.Finally,the green-emitting CsPbBr3@MIL-53 nanocomposite phosphors were applied to white LED devices,achieving a wide-color-gamut coverage area of 126％NTSC and 85％Rec.2020,which demonstrates its application prospects in wide-color-gamut display devices.
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