聚对苯基苯并二噻唑及聚-2,2'-间苯基-5,5'-二苯并咪唑体系发光性质的理论研究

我们利用理论计算方法对两类聚合物: 聚对苯基苯并二噻唑(PTB)和聚-2,2'-间苯基-5,5'-二苯并咪唑(PBI)进行研究, 计算两类聚合物的性质并对其共混聚合物的性质进行预测. 我们通过计算可以知道, PTB为具有良好平面性的全共轭刚性聚合物, 而PBI为卷曲型的部分共轭聚合物. 计算两类聚合物的电离能、电子亲和势. 比较后发现PTB具有较好电子注入和传输能力, 而PBI的空穴注入和传输能力比PTB稍好. 与PTB相比, PBI的吸收与发射光谱蓝移. 文章还预测PTB/PBI共混体系的发光性质. 在全共轭PTB中添加部分共轭PBI以改善加工性能的同时, 改善空穴的注入及传输能力, 但会使体系的吸收及发射光谱蓝移.

Theoretical Investigation on the Luminescent Properties of PTB/PBI Copolymer

The monomers and oligomers of the PTB (poly-p-phenylenebenzobisthiazole, n＝1～5) and PBI (poly-2,2'-m-phenylene-5,5'-bibenzimidazole, n＝1～4) have been studied using the density functional theory. Through computation the following information can be got: PTB, a fully conjugated rigid-rod polymer has better electron injection and transportation ability, while PBI, a partially conjugated coil-like polymer has better hole injection and transportation ability. The maximum absorption and emission wavelength of PBI are shorter than those of PTB, eg. the absorption and emission spectrum of PBI are blue-shifted compared with PTB. A addition of partially conjugated PBI into the fully conjugated PTB can improve the processibility as well as hole injection/transportation ability. And the absorption and emission spectrum of PTB/PBI will be blue-shifted.