引用本文:
【打印本页】   【HTML】   【下载PDF全文】   View/Add Comment  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 1428次   下载 1374 本文二维码信息
码上扫一扫!
分享到: 微信 更多
Theoretical Study on Optical Properties of Oligo°uorenes
Jian Song*,Yu-fang Liu
Author NameAffiliationE-mail
Jian Song* Department of Physics, Henan Normal University, Xinxiang 453007, China songjian@mail.ustc.edu.cn 
Yu-fang Liu Department of Physics, Henan Normal University, Xinxiang 453007, China  
Abstract:
We present theoretical investigations on structure-property correlations in fluorenone (FLO) and benzothiadiazole (BT) substituted oligofluorenes (OFLs) derived mainly from the chain morphology, thermal vibration and conjugated extent. Both the vertical absorptions and the vibrationally-resolved absorption and fluorescence spectra have been calculated by the com-bination of ab initio and time-dependent density functional theory. By properly taking into account of the anharmonic torsion potentials in the OFLs, we have reasonably reproduced the experimentally observed spectroscopic features. Both FLO and BT on-chain chemical defects acting as charge-trapping sites for singlet excitations, are responsible for long wave absorption and emission species, and thus alter the blue light-emitting properties of OFLs. As temperature decreases, the electronic spectral lineshapes of FLO-substituted oligomers become more structured. The lineshapes of BT-substituted oligomers are always smooth and featureless because of less low collective modes resonance. A more gentle excited poten-tial energy surface of BT-mixed molecules can enhance electronic delocalization and achieve bigger red shifts.
Key words:  Oligofluorene, Electronic spectroscopy, Time-dependent density functional theory, Vibrationally-resolved
FundProject:
芴酮及苯并噻二唑取代的低聚芴环光学特性的理论研究
宋建*,刘玉芳
摘要:
从链形态、热振动及共轭特性等方面系统的研究了芴酮及苯并噻二唑取代的低聚芴环引起的光学性质的变化. 采用从头算和含时密度泛函方法计算了模型体系的垂直吸收光谱和包含振动结构的吸收和发射光谱. 通过合理的考虑低聚芴环间扭转模式的非谐性效应,理论光谱和实验光谱得到了很好的吻合. 芴链上掺杂的芴酮和苯并噻二唑均具有电子捕获特性,使得整个分子的吸收带变宽且发射光谱红移,从而起到了调制纯芴链发光特性的作用. 当温度升高时,芴酮掺杂的低聚芴的光谱谱型会变得复杂,含有更多的振动结构. 苯并噻二唑掺杂的低聚芴的光谱线型始终比较光滑,几乎没有振动结构,这是因为在低频模式在苯并噻二唑环上很难找到共振. 苯并噻二唑掺杂的低聚芴的激发态势能面更平缓,这有利于增强电子的离域,从而得到更大的光谱红移.
关键词:  低聚芴,吸收和发射光谱,振动分辨,含时密度泛函
DOI:10.1063/1674-0068/26/04/409-414
分类号: