Synthesis, luminance and ultraviolet resistance of a copolymer phosphor of Eu-complex and siloxane in near UV-based LED.

In copolymer phosphors with Eu(III), the majority have difficulty in resisting aging by UV light. In this paper, a novel copolymer phosphor with high thermal resistance and good ultraviolet aging resistance was synthesized by radical polymerization from the Eu-complex and siloxane. Intense red emission peaked at 613 nm, corresponding to the D → F transition of Eu(III) ions, was observed under UV excitation. The fluorescence lifetime is calculated as 0.586 ms, with a loss of 0.003 ms after aging for 150 h. The thermal stability shows excellent resistance to high temperature, and the initial decomposition temperature is 153 °C, which meets the requirement of LED operating temperature. The CIE of the LED device is (0.625, 0.308) under excitation at 365 nm. The LED device fabricated with the copolymer and a near-UV LED chip shows bright pure-red emission and good resistance to UV aging. This shows that the copolymer phosphor can be used as an efficient red phosphor in WLEDs. [ABSTRACT FROM AUTHOR]