A red-emitting copolymer phosphors based on bimetallic Eu-Ir complex for Near-UV chip-based LEDs
In this paper,a new Eu-Ir bimetallic complex Eu(FIrPic)2(Phen)UA is synthesized using the Ir complex FIrPic as ligands for Eu ions and red-emitting phosphorescent copolymer PM-Eu-Ir is successfully prepared via radical polymerization for commercial near UV chip-based LEDs.The Eu3+ ions were found to be effectively sensitizable by adding Ir-complex with enhanced ultra-violet light absorption at around 400 nm without affecting the fluorescence emission characteristic of the Eu3+ ions.The proposed copolymer PM-Eu-Ir exhibits the strongest emission peak at 612 nm with the CIE coordinates(0.461,0.254)under 365 nm ultra-violet light excitation,which matches well with the 365 nm near-UV chip.The micro-morphology of the red copolymer phosphor PM-Eu-Ir is a typical multilayer spatial network structure;as well as having appreciable red emission and the corresponding fluorescence lifetime of 634.54 μs,it also has excellent thermal stability in a wide range of 25～250℃.The LEDs fabricated by the copolymer PM-Eu-Ir display red light emission with a 149800 cd/m2 luminance.The results support the potential utilization of prepared copolymer phos-phor as a red component in the fabrication of near UV chip-based white LEDs.
rare-earth luminescent ionsbimetallic complexescopolymer phosphorsNUV LED chips
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