A red-emitting copolymer phosphors based on bimetallic Eu-Ir complex for Near-UV chip-based LEDs

In this work, a new Eu-Ir bimetallic complex Eu(FIrPic)2(Phen)UA is synthesized using the iridium complex FIrPic as ligands for europium 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 could be effectively sensitized by the addition of Ir-complex with the enhancement of ultra-violet light absorption at around 400 nm, without affecting the characteristic fluorescence emission 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, besides 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 ℃.