Synthesis,Luminescence Properties and White Light LED Applications of Ligand-modulated CsPbBr3/Cs4 PbBr6 Composite Films
Synthesis of all-inorganic CsPb X3(X=Cl,Br,I)perovskite nanocrystals(PNCs)typically requires high-temperature conditions and the involvement of inert gases,which severely hinders their practical application.In this work,a room-temperature method using a 2-methylimidazole ligand to regulate recrystallization was first em-ployed to successfully prepare biphase CsPbBr3/Cs4PbBr6 PNCs with superior luminescent properties.Subsequently,these nanocrystals were combined with various polymers to fabricate nanocrystal composite films.The biphase perovskite structure within the polymers was confirmed through XRD,TEM,and UV-Vis absorption spectroscopy.The CsPbBr3/Cs4PbBr6@PDMS and CsPbBr3/Cs4PbBr6@EVA composite films were identified as having excellent over-all performance,and they were encapsulated in LED devices.With dual protection from Cs4PbBr6 PNCs and the polymers,the CsPbBr3/Cs4PbBr6@PDMS exhibited a photoluminescence quantum yield(PLQY)exceeding 80%,while the water stability and air stability of CsPbBr3/Cs4PbBr6@EVA were significantly enhanced.Finally,the CsPb-Br3/Cs4PbBr6@EVA composite film was successfully applied to white LED devices,emitting standard white light with a CIE chromaticity coordinate of(0.331,0.332).
ligand regulationCsPbBr3/Cs4PbBr6composite filmwhite LED device
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