Theoretical Investigation on the Luminescent Properties of Polyfluorene and Poly(fluorene-co-thiophene)  

作　　者：FENG Ji-kang ZHANG Jing-hua REN Ai-min RAN Xue-qin LI Yuan-yuan 

机构地区：[1]State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry [2]College of Chemistry, Jilin University, Changchun 130021, P. R. China

出　　处：《Chemical Research in Chinese Universities》2009年第5期711-718,共8页高等学校化学研究（英文版）

基　　金：Supported by the State Basic Research Development Program of China(No.2002CB613406);the National Natural Science Foundation of China(No.20673045);the Open Project of State Key Laboratory of Superamolecular Structure and Materials of Jilin University(No.SKLSSM200716)

摘　　要：The density functional theory was employed to study the structures, ionization potentials（IPs）, electron affinities（EAs）, and HOMO-LUMO gaps（ΔH-L） of the oligomers. The time-dependent density functional theory（TD-DFT） and ZINDO were employed to study the lowest excitation energies（Egs） and the absorption and emission spectra of the oligomers of polyfluorene（PF） and poly（fluorene-co-thiophene）（PFT）. By extrapolating ΔH-L and Egs to those of infinite chain length, band gaps and effective conjugation lengths of the corresponding polymers were obtained. The IPs, EAs and 2abs of the polymers were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero（I/n=0）. The outcome shows the decreased dihedral angle between fluorene and thiophene units in the PFT compared to that between fluorene units in the PF results in the increased efficient conjugation of PFT. These cause both the maximal absorption and emission wavelengths of PFT red-shifted compared with those of PF.The density functional theory was employed to study the structures, ionization potentials（IPs）, electron affinities（EAs）, and HOMO-LUMO gaps（ΔH-L） of the oligomers. The time-dependent density functional theory（TD-DFT） and ZINDO were employed to study the lowest excitation energies（Egs） and the absorption and emission spectra of the oligomers of polyfluorene（PF） and poly（fluorene-co-thiophene）（PFT）. By extrapolating ΔH-L and Egs to those of infinite chain length, band gaps and effective conjugation lengths of the corresponding polymers were obtained. The IPs, EAs and 2abs of the polymers were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero（I/n=0）. The outcome shows the decreased dihedral angle between fluorene and thiophene units in the PFT compared to that between fluorene units in the PF results in the increased efficient conjugation of PFT. These cause both the maximal absorption and emission wavelengths of PFT red-shifted compared with those of PF.

关 键 词：POLYFLUORENE Poly（fluorene-co-thiophene） Luminescent property 

分 类 号：O626.12[理学—有机化学] TN104.3[理学—化学]