A series of electrophosphorescent conjugated fluorene-alt-carbazole copolymers were designed.Metal complex iridium(Ⅲ) bis-(9

9-diethyl-9H-fluoren-2-yl) pyridine (IrFpy) is grafted in the N-alkyl group of carbazole by covalent bond linkage.The copolymers were synthesized by Suzuki polycondensation

the content of metal iridium complex (IrFpy) was 0.25 mol%

0.5 mol% and 1 mol%

respectively.The yellowish light was obtained with the CIE of (0.44

0.56) with the Ir complex (IrFpy) molar ratio in the copolymer of 1 mol%.With the decrease of iridium complex content

the single white light emitting copolymers were obtained due to the incomplete quench of the blue light emission.The electroluminescent devices were fabricated with configuration of ITO/PEDOT:PSS (50 nm)/polymer + PBD (30 wt%) (80 nm)/Ba (4 nm)/Al (150 nm).The best device performance was achieved based on the polymer PF-IrFpy025

which exhibited a maximal luminous efficiency of 3.97 cd/A with CIE of (0.34

0.34)

which are very close to the pure white-light point of (0.33

0.33).To investigate the electroluminescent stabilities of white light emitting copolymers PF-Fpy025 and PF-Fpy05

electroluminescent spectra were tested with voltage from 8 V to 13 V.The two copolymers both showed good electroluminescent stabilities

when the voltage was increased from 8V to 13 V.This result indicated that incorporation of the phosphorescent complex into the conjugated polymer side chains was an effective strategy to simultaneously realize high efficiency and relatively stable electroluminescence of phosphorescent polymer white light emitting diodes.