新型低带隙聚合物结构和性质的理论研究  

Theoretical analysis on the electronic structure and properties of novel low-band-gap polymers

作　　者：邓理丹[1] 李明[1] 解晓华[1] 刘彬瑶[1] 申伟[1] 

机构地区：[1]西南大学化学化工学院,重庆400715

出　　处：《中国科学：化学》2012年第7期1066-1077,1107-1108,共12页SCIENTIA SINICA Chimica

基　　金：国家自然基金(21073144);教育部博士点基金(200806350013);重庆市自然基金(CSTC;2009BB4104);中央高校基本科研业务费(XDJK2010B009)资助

摘　　要：本文将3,4-次乙烯二氧噻吩(VDOT)与噻吩并[3,4-b]吡嗪(TP),呋喃并[3,4-b]吡嗪(FP)和6H-吡咯并[3,4-b]吡嗪(PP)组合,获得了一系列3,4-次乙烯二氧噻吩衍生物.采用密度泛函理论(DFT)在B3LYP/6-31G*理论水平下对其单体、低聚物和聚合物的结构和电子性质进行了深入的理论研究.通过分析键长的变化、中心键性质,Wiberg键级(WBI)以及核独立化学位移,发现随着聚合度的增加物质的共轭性也随之增加.为了了解不同的VDOT与TP、FP、PP比例对电子性质的影响,对V-P比例为1:1、1:2和2:1时的计算结果进行了对比分析,结果表明,V-P比例为1:2化合物共轭性最好,而2:1的共轭性最差.由于1:2的二聚物具有较大的电子迁移速率,其相应的聚合物可能是潜在的电子传输材料.同时,聚合物的能带结构显示V-P比例为1:1的聚合物(包括(VDOT-TP)n,(VDOT-FP)n和(VDOT-TP)n)具有相对低的带隙和很宽的带宽,可以做为潜在的导电材料.另外,(VDOT-BTP)n和(VDOT-BFP)n有着非常低的带隙(分别为0.73和0.87eV),且拥有合适的带宽,也是良好的本征导电材料.In this work,A series of novel co-polymers which are obtained by combining 3,4-vinylene-dioxythiophene（VDOT） with thieno[3,4-b]pyrazine（TP）,furo[3,4-b]pyrazine（FP） and 6H-Pyrrolo[3,4-b]pyrazine（PP） are prepared.The structures and electronic properties of those polymers as well as their corresponding monomers and oligomers are studied by the density function theory（DFT） at B3LYP level with 6-31G＊.The change of the bond lengths,bond critical point（BCP） properties,Wiberg bond index（WBIs） and nucleus-independent chemical shift（NICS） show that the conjugational degree is increased with main chain extension.To understand the effect of the ratio of VDOT to TP,FP and PP unit（V-P ratio） for electronic properties of investigated compounds,those compounds with the V-P ratio of 1：1,1：2 and 2：1 are analyzed.The results show that the conjugational degree of oligomers with 1：2 V-P ratio is the best and that of oligomers with 2：1 V-P ratio is the worst.The small electron-transfer reorganization energy indicates polymers with 1：2 and 2：1 V-P ratio may be potential electron transport materials.The band structure analysis shows that all of polymers with 1：1 V-P ratio which include（VDOT-TP）n,（VDOT-FP）n and（VDOT-TP）n have relatively narrow band gap and very large bandwidth.Therefore,those polymers can be considered as potential organic conductive materials.In addition,（VDOT-BTP）n and（VDOT-BFP）n have quite low band gap（0.73 and 0.87 eV,respectively） and suitable bandwidth which indicate that they may be good intrinsic conductors.

关 键 词：3 4-次乙烯二氧噻吩 密度泛函理论 电子性质 带隙 导电材料 

分 类 号：O631.3[理学—高分子化学]