氟代寡聚噻吩系列衍生物的载流子传输性质的理论研究

基于密度泛函理论方法,采用Marcus电荷转移公式,分别从几何和电子结构、重组能、转移积分及迁移率等方面研究了氟代寡聚噻吩系列衍生物中噻吩环个数、全氟代苯位置的改变及F原子的引入对体系载流子传输性质的影响.计算结果表明,化合物1b,1c和1d的电子迁移率随着噻吩单元个数的增加而逐渐升高,因此可以通过增加噻吩单元个数来提高其电子迁移率;而对于化合物1d,2a和2b而言,氟代苯位置的改变对传输性质产生了较大的影响,其中化合物1d具有良好的平面性和π-π堆积,传输性能最好,有望成为良好的双极性传输材料;比较化合物2b与3可以发现,F原子的引入增大了化合物2b的载流子迁移率,为实验设计高迁移率的传输材料提供了理论依据.

Theoretical Studies on Carrier Transport Properties of Oligofluorenythiophene Compounds

Oligothiophene derivatives,as typical carrier transport materials,have received considerable attention.The influence of the thiophene chain length,variation of the substituents and the incorporation of fluoro were investigated by combining density functional theory(DFT) with Marcus theory,focusing on geometries and electronic structures,intramolecular reorganization energy,intermolecular transfer integral and hopping rate.The results show that the electronic hopping rate increases with the increasing of thiophene chain length in the order of compound 1b to 1d.Among compounds 1d,2a and 2b,compound 1d has the best carrier transport properties due to its better face-to-face π-stacked structure.Compared compound 2b with compound 3,the incorporation of fluoro may be beneficial to the improvement of the stability and transport ability.