导　　师： 王学业

学科专业： 070304

授予学位： 硕士

作　　者： ;

机构地区： 湘潭大学

摘　　要： 近年来,聚合物发光材料的分子设计合成及聚合物发光机理和EL器件的研究成为最具有活力的研究领域。本文用量子化学方法系统研究了如下4个体系:/(1/)系列噻吩和吡啶共聚物;/(2/)咔唑和吡啶交替聚合物;/(3/) 2,7-咔唑和3,6-咔唑三聚物;/(4/)苯酚-吡啶硼配合物。 首先,采用密度泛函理论/(DFT B3LYP/)及3-21G*基组方法,对一系列含π-富电子烷基噻吩和间位或对位连接的π-缺电子吡啶共聚物聚/(3-辛基-噻吩-2,6-吡啶/)/(p1/),聚/(3-辛基-噻吩-2,6-吡啶-3-辛基噻吩/)/(p2/),聚/(3-辛基-噻吩-2,5-吡啶-3-辛基噻吩/)/(p3/),在中性、阴离子态和阳离子态下分别进行几何结构优化计算。用含时密度泛函理论/(TD-DFT//B3LYP/)及3-21G*基组计算吸收光谱;同时用ab initio HF单激发组态相互作用/(CIS/)法在3-21G*基组上优化其最低激发单重态几何结构,用含时密度泛函理论计算发射光谱。结果表明,共聚物主链中吡啶成分减少导致HOMO能级上升和LUMO能级下降,吡啶基团的对位连接更加剧了这一影响,从而改善了注入和传输空穴和电子的能力。另外,共聚物主链中吡啶成分减少以及吡啶的对位连接导致了能隙的变窄和吸收及荧光波长的红移。 其次,采用密度泛函理论/(DFT//B3LYP//6-31G/)研究了由咔唑和吡啶单元交错形成的三种A-B型荧光共聚物,聚/(2,7-N-2-乙基己基咔唑/)-交替-3,5-吡啶/(PEHCP-35/),聚/(2,7-N-2-乙基己基咔唑/)-交替-2,6-吡啶/(PEHCP-26/)和聚/(2,7-N-2-乙基己基咔唑/)-交替-2,5-吡啶/(PEHCP-25/)。基于优化的几何结构,应用含时密度泛函理论/(TD-DFT/)计算了它们的光学性质。PEHCP-35和PEHCP-26的能隙和光学性质迅速达到饱和。从实验可知PEHCP-25实际上是聚合度为4的齐聚物。因此本文采用PEHCP-35,PEHCP-26,PEHCP-25的四聚物作为主要研究模型来分析它们的电子结构和光谱性质,且计算结果与实验值符合较好。共聚� Recently, the molecular design, synthesis and the luminescent mechanism of the luminescent polymer materials become one of the most active fields. The paper applied the quantum chemistry methods and systematically studied the following 4 systems: /(1/) poly/(alkylthiophene-co-pyridine/)s; /(2/) carbazolyl-pyridinyl alternating copolymers; /(3/) 2,7- linked and 3,6-linked carbazole trimers /(4/) phenol-pyridyl boron complexes. Firstly, quantum-chemical techniques were applied to investigate a series of conjugated polymers: poly/(3-octylthien-2,5-ylene-co-pyrid-2,6-ylene/) /(p1/), poly/[/(pyrid-2,6-ylenebis/(3-octylthien-2,5-ylene/)/) /(p2/) and poly/[pyrid-2,5-ylenebis/(3-octylthien-2,5-ylene/)/] /(p3/), comprising alternatingπ-excessive 3-alkylthiophene andπ-deficient meta- or para-linked pyridine moieties. Their ground state and excited state structures were optimized with density functional theory B3LYP method at 3-21G* level, and the optical properties were calculated by the time-dependent density functional theory /(TD-DFT/) and ZINDO//S methods. Their HOMO-LUMO gaps /(△H-L/), the lowest excitation energies /(Eg/), ionization potentials /(IP/) and electron affinities /(EA/) were obtained by extrapolating those of the polymers to the inverse chain length equal to zero /(1//n=0/). The calculated results showed that the decrease of the pyridylene content and the para-linked pyridylene in the backbone of the polythiophene resulted in a narrowed energy gap and bathochromic absorption and emission peaks. Secondly, three A-B-type fluorescent copolymers comprised of alternating carbazolyl and pyridinyl units, poly/[/(2,7-/(N-/(2-ethylhexyl/)carbazolyl/)-alt-/(3,5-pyridinyl/)/)/]/(PEHCP-35/), poly/[/(2,7-/(N-/(2-ethylhexyl/)carbazolyl/)-alt-/(2,6-pyridinyl/)/)/]/(PEHCP-26/) and poly/[/(2,7-/(N-/(2-ethyl- hexyl/)carbazolyl/)-alt-/(2,5-pyridinyl/)/)/]/(PEHCP-25/), are studied by means of the density functional theory /(DFT//B3LYP//6-31G/). Based on the optimized geometries, the optical properties are

关 键 词： 含时密度泛函理论 电离能 电子亲和势 吸收光谱 发射光谱

领　　域： [理学] [理学]