含Alq_3和咔唑侧基共聚物的合成及其光性能

Synthesis and Optical Properties of Copolymers Containing both of Alq_3 and Carbazole Side Groups

三(8-羟基喹啉)铝(Alq3)是公认的性能优良的电子传输型电致发光材料,若能将其高分子化并同时引入空穴传输结构(如咔唑结构),则有望获得具有均衡电荷传输能力和良好成膜性能的新型电致发光高分子材料。文章合成了两种分别含8-羟基喹啉结构和咔唑结构的甲基丙烯酸酯单体(1b和2b),两者以不同的比例进行共聚反应合成了一系列两单体配比分别为n(1b)∶n(2b)=1∶9,2∶8和4∶6的共聚物,共聚反应单体总转化率在90%左右,所得共聚物的Mn介于14 000～20 000。所得共聚物与二(2-甲基-8-羟基喹啉)乙基铝(EtAlq'2)进行配位反应,获得了含Alq3和咔唑侧基的甲基丙烯酸酯共聚物,利用紫外吸收光谱和荧光光谱对所得共聚物的光性能进行了初步研究。结果表明,所得共聚物的荧光光谱表现为Alq3的特征荧光,并随共聚物中Alq3含量的增加,荧光强度增强;共聚物中咔唑结构的引入使共聚物的荧光相对于Alq3发生红移,并随咔唑结构含量的增加,红移幅度加大。

Tris（8-hydroquinolinato） aluminum（Alq3） is one of the best electroluminescent materials with excellent electron-transporting ability.Integrating hole-transporting segments and Alq3 into the same polymer may effectively improve the electroluminescent properties of Alq3 because of more balanced charge transports of both carriers.Two methacrylate monomers containing 8-hydroxyquinoline or carbazole group were synthesized,respectively.Then,a series of copolymers,containing both 8-hydroxyquinoline and carbazole side groups with different ratios,were synthesized by the copolymerization of these two monomers with different ratios initiated by AIBN at 60 ℃ for 72 h.The obtained copolymers were characterized by 1H NMR and GPC analyses.The total conversions of monomers were around 90%,and the molecular weights（Mn） of the copolymers were between 14 000 and 20 000.The obtained copolymers were then complexed with di（2-methyl-8-hydroquinolinato）-ethylaluminum（EtAlq＇2） to give copolymers containing both Alq3 and carbazole side groups.The optical properties of the obtained polymeric complex were investigated by UV-vis and photoluminescence spectroscopy.The results showed that the absorption of carbazole trail off and the absorption of Alq3 increased with the increasing ratio of Alq3.The emission intensity increased with increasing ratio of Alq3,and the λmax in emission was red-shifted with increasing ratio of carbazole side group.