含联二萘的PPV类共轭聚合物发蓝光材料的设计合成

利用Wittig和Wittig-Horner反应合成了四种含有联二萘和不同芳香基团的具有线性或超支化结构的发光共聚物,并对共聚物的光物理性质和电化学性质进行了研究。结果表明,这些线性共聚物都具有较高效率的蓝光发射。具有超支化结构的共聚物BN-TPPV在氯仿溶液中的荧光量子效率高达95%,在氯仿溶液和膜中的发射光谱峰值分别位于393,428nm,实现了高效率的蓝光发射。说明将联二萘生色团引入聚合物是一种实现发蓝光材料的重要途径。

Design and Synthesis of PPV Conjugated Light-emitting Polymers Containing Binaphthalene

Conjugated polymers as light emitting materials have attracted considerable attention during the past several decades. There is substantial ongoing research towards the design of blue light emitting materials for OLEDs based on conjugated polymers. The conjugation length, steric hindrance within the polymer, must be controlled for such purpose. It is well known that the binaphthyl unit possesses a large dihedral angle ranging from 60° to 120°. Therefore, the conjugation of the binaphthyl-containing polymers can be interrupted by the highly twisted binaphthyl unit. In addition, the highly twisted structure will reduce the intermolecular interaction of the polymers. As a result, the binaphthyl-containing polymers will have high quantum efficiency and good solubility. Binaphthalene chromophores were introduced into the backbone of conjugated copolymers with different aromatic groups by Wittig or Wittig-Horner reaction, three linear copolymers and a hyperbranched (copolymer) containing binaphthyl unites were synthesized. All the copolymers were characterized by FT-IR, (¹H NMR.) They were readily dissolved in the common solvents such as tetrahydrofuran(THF), dichloromethane, and chloroform. Their photophysical properties have been studied. The results indicated that all copolymers show pure blue light emitting. It is mentionable that the hyperbranched copolymer BN-TPPV shows the highest quantum efficiency (95%) among the four copolymers, which exhibits two emission band peaked at 393 nm and 410 nm in chloroform and one broad emission band peaked at 428 nm in solid film. Cyclic voltammetry was employed to investigated the electrochemical properties of the polymers, their band gaps were ranging from 2.76 eV to 3.05 eV, this result testified that the polymers, BN-PPV, BN-PBPV, BN-TPPV, have the potential to be applied as blue light emitting materials. The results show that it is a practical way to prepare blue light emitting polymers by incorporating binaphthyl into polymer chain.