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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (8): 673-677. 上一篇    下一篇

研究论文

芴-硫芴共聚物的电子结构和光谱性质的理论研究

刘彬1, 封继康*,1,2, 任爱民1, 杨丽1, 邹陆一1   

  1. (1吉林大学理论化学研究所理论化学计算国家重点实验室 长春 130023)
    (2吉林大学化学学院 长春 130023)
  • 投稿日期:2006-06-29 修回日期:2006-09-23 发布日期:2007-04-28
  • 通讯作者: 封继康

Theoretical Investigation on Electronic Structure and Optical Proper-ties of Polyfluorene by Copolymerization with Dibenzothiophene

LIU Bin1; FENG Ji-Kang*,1,2; REN Ai-Min1; YANG Li1; ZOU Lu-Yi1   

  1. (1 State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chem-istry, Jilin University, Changchun 130023)
    (2 College of Chemistry, Jilin University, Changchun 130023)
  • Received:2006-06-29 Revised:2006-09-23 Published:2007-04-28
  • Contact: FENG Ji-Kang

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用DFT-B3LYP方法对低聚物(PF30T)n [n(芴)∶n(硫芴)＝2∶1, 物质的量之比, n＝1～4], (PF50T)n [n(芴)∶n(硫芴)＝1∶1, 物质的量之比, n＝1～4]体系全优化, 得到两系列低聚物的电离能(IP(a,v))、电子亲和势(EA(a,v))、空穴抽取能(HEP)、电子抽取能(EEP). 在此基础上用ZINDO和TD-DFT方法计算吸收光谱, 分析了两个系列的HOMO-LUMO能隙随着n递增的变化趋势及硫芴含量对低聚物电子结构和光谱性质的影响, 推断了高聚物的电子和光谱性质. 用ab initio CIS方法优化了低聚物的S1激发态结构并分析了其与发射光谱的关系. 研究显示: 2,8位引入的硫芴基团, 破坏了链的共轭, 而且随着硫芴含量的增加, HOMO-LUMO能隙变大, 光谱蓝移; 激发态结构趋于共面化.

关键词: 聚合物, 密度泛函理论(DFT), 光谱性质

We have full optimized the structures of the oligomers of (PF30T)n [n(fluorene)∶n(dibenzothiophene)＝2∶1, n＝1～4] and (PF50T)n [n(fluorene)∶n(dibenzothiophene)＝1∶1, n＝1～4] with DFT/B3LYP method, and calculated the IP(a,v), EA(a,v), HEP and EEP. Using TD-DFT and ZINDO methods on the structures of the optimized oligomers, we analyzed the trend of the variation of HOMO-LUMO gaps with 1/n and the influence on the spectral properties with the increasing of dibenzothiophene, and extrapolated the electronic structure and optical properties of the polymers. We optimized the S1 excited ge-ometries with ab initio CIS and studied the relation of S1 state and emission spectra. It shows that all atoms come to coplanar in S1 state. The results show that, with introducing dibenzothiophene at the 2,8 positions of fluorene, the conjugation is broken, the HOMO-LUMO gaps are broader, and the spectrum is blue-shifted.

Key words: polymer, density functional theory, optical property