端基对二噻吩和苯并噻吩类共轭桥化合物电子结构及载流子传输性能的影响  

Terminal Group Effects on Electronic Structure and Carrier Transport Property of Conjugated Bridge of Bithiophene and Benzodithiophene

作　　者：杜松松[1] 李春荣[2] 赵春梅[1] 魏妮[1] 王文亮[1] 

机构地区：[1]陕西省大分子科学重点实验室陕西师范大学化学与材料科学学院,西安710062 [2]长安大学环境科学与工程学院,西安710054

出　　处：《化学学报》2011年第10期1151-1159,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20873079)资助项目

摘　　要：采用密度泛函理论(DFT,TDDFT)B3LYP/6-31G(d)和PBE0/6-31G(d)方法对苯乙烯/乙炔为端基,二噻吩(2T)、苯并二噻吩(TPT)和二苯并噻吩(PTP)为共轭桥的12个化合物进行了系统地计算研究.在分别优化中性态与离子态几何构型的基础上,获得了前线轨道能级、电离能(IPs)、电子亲合能(EAs)、重组能(λh/λe)和电子吸收光谱等信息.结果表明,苯乙炔基取代苯乙烯基对LUMO能级影响很小,但HOMO能级明显降低,能级差?E和激发能Ev增大,吸收光谱蓝移10～30 nm,多数苯乙炔基化合物的重组能均有所降低;端基相同共轭桥分别为2T,TPT和PTP时,HOMO能级逐渐降低,LUMO能级逐渐升高,?E和Ev依次增大,吸收光谱依次蓝移30～45 nm.研究结果还表明,TPT共轭桥化合物的重组能较小,且λh与λe相近,有利于载流子传输平衡,提高传输速率.本文设计的苯乙炔基苯并二噻吩(DPATPT)有望成为潜在的传输效率高、抗氧化能力强的载流子传输材料.Twelve compounds,taking styrene or phenylacetylene as terminal group,bithiophene（2T）,benzodithiophene（TPT） and dibenzothiophene（PTP） as conjugated bridges,were studied by density func-tional theory（DFT,TDDFT） at the B3LYP/6-31G（d） and PBE0/6-31G（d） level.Based on optimized geome-tries in the neutral state and ionic state,frontier orbital energies,ionization potentials（IPs）,electron affini-ties（EAs）,reorganization energy（λh/λe） and electronic absorption spectrum were obtained.Results show that styrene as terminal group was replaced by phenylacetylene,the lowest unoccupied molecular orbital（LUMO） energy level was little affected while the highest occupied molecular orbital（HOMO） energy level was obviously lowered.Consequently,the HOMO-LUMO energy gaps（ΔE） were increased and absorption spectrum were blue-shifted about 10～30 nm.In addition,reorganization energy（λh/λe） of majority phenylethynyl compound were decreased.As for different conjugated bridge（2T,TPT and PTP,respec-tively） with the introduction of same terminal group,the HOMO energy level was lowered,the LUMO en-ergy level was heightened,so the HOMO-LUMO energy gap（ΔE） increased with the absorption spectrum blue-shift of 30～45 nm.Moreover,the compounds with TPT conjugated bridge are easier to balance carrier transport and improve carrier transport rate,due to small reorganization energy and close reorganization en-ergies of the hole and the electron.The diphenylacetylene-benzodithiophene（DPATPT） is expected to be-come a potential carrier transport material with high transport efficiency and strong antioxidant ability.

关 键 词：苯乙烯/苯乙炔基 二噻吩 苯并二噻吩 二苯并噻吩 密度泛函理论 载流子传输 

分 类 号：O641.1[理学—物理化学]