Synthesis and luminescence properties of long-chain (2,7-carbazolyl)-adamantane copolymers

Several long-chain (2,7-carbazolyl) adamantane copolymers, with molecular weight ranging from 4500 to 6000, were synthesized by palladium-catalyzed Suzuki reaction using 1,5-bis (4-bromophenyl) adamantane and N-(2-ethylhexyl)-2,7-carbazole as building molecules. The copolymers were characterized by infrared, ultraviolet, nuclear magnetic resonance (NMR), fluorescence spectroscopies, and thermal analysis. It was found that the introduction of adamantyl group into the backbone of conjugated carbazole polymer significantly improves the thermal stability and spectral stability of the copolymer. These copolymers giving high color purity showed excellent comprehensive performance: the thermal decomposition temperature is up to 409 ~ 432 °C, glass-transition temperature is about 83 ~ 162 °C, fluorescence quantum efficiency is as high as 0.76 ~ 0.85. Hence, the synthesized copolymers have great potential for being used as new blue-light-emitting materials.