基于3,6-二氯噻吩并[3,2-b]噻吩的共轭聚合物的直接芳基化缩聚合成及其半导体性质  

Conjugated Polymers Based on 3,6-Dichlorothieno[3,2-b]thiophene Synthesized by Direct Arylation Polycondensation and Their Semiconductor Properties

作　　者：林琳琳 张栩文 石毅博 邓云峰 耿延候[1,2] Lin-lin Lin;Xu-wen Zhang;Yi-bo Shi;Yun-feng Deng;Yan-hou Geng(School of Materials Science and Engineering,Tianjin University,Tianjin 300350;Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Fuzhou 350205)

机构地区：[1]天津大学材料科学与工程学院,天津300350 [2]天津大学-新加坡国立大学福州联合学院天津大学国际校区,福州350205

出　　处：《高分子学报》2024年第1期36-47,共12页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号51933008,22222506,52121002)资助项目。

摘　　要：以β位氯代的噻吩衍生物3,6-二氯噻吩并[3,2-b]噻吩(2ClTT)为C-H单体、溴代噻吩取代吡咯并吡咯二酮(DPPC14-Br)或溴代异靛蓝(IIDC14-Br)为C-Br单体,采用直接芳基化缩聚(DArP)合成了共轭聚合物DPP-2ClTT和IID-2ClTT.氯原子的引入可大幅提高并噻吩α-C-H键的反应活性,理论计算表明,2ClTT的直接芳基化反应活性与文献报道的高活性氯代联噻吩C-H单体的活性相当.此外,利用氯原子较强的电负性,可以降低聚合物的前线轨道能级,DPP-2ClTT和IID-2ClTT的HOMO/LUMO能级分别为-5.35/-3.66 eV和-5.88/-3.73 eV.由于具有合适的HOMO和LUMO能级以及离域的HOMO和LUMO轨道,以DPP-2ClTT为活性层制备的有机薄膜晶体管(OTFT)表现出双极传输特性,最高电子和空穴迁移率分别为1.36和0.89 cm^(2)/V/s. IID-2ClTT具有较低的HOMO能级以及较为定域的HOMO轨道,因而该聚合物在OTFT器件中表现出n型传输特性,最高电子迁移率为0.029 cm^(2)/V/s.相比于IID-2ClTT,DPP-2ClTT高的电子迁移率可归因于其好的骨架平面性、有序的分子堆积以及优异的薄膜形貌.Direct arylation polycondensation(DArP)is an atom-economic and environmentally benign protocol for the synthesis of conjugated polymers.However,this method often suffered from low reactivity and poor selectivity of C-H bonds.In this study,aβ-chlorinated thiophene derivative,3,6-dichlorothieno[3,2-b]thiophene(2ClTT),was used as the C-H monomer for DArP.The introduction of chlorine atoms at theβ-positions of thieno[3,2-b]thiophene significantly enhances the reactivity ofα-C-H bonds and evades the unwanted C-H activation.Theoretical calculations revealed that the DArP reactivity of 2ClTT is comparable to that of highly reactiveβ-chlorinated thiophene-based C-H monomers reported in previous literature.Two conjugated polymers,i.e.,DPP-2ClTT and IID-2ClTT,were synthesized by using 2ClTT as the C-H monomer and bromothienyl-flanked diketopyrrolopyrrole(DPPThBr)or brominated isoindigo(IIDBr)as the C-Br monomers.The photophysical and electrochemical properties of these two polymers were investigated.The absorption spectrum of DPP-2ClTT was redshift by⁓200 nm compared to that of IID-2ClTT.This can be ascribed to the planar backbone of DPP-2ClTT due to the presence of Cl···S intramolecular interactions.Furthermore,the strong electronegativity of chlorine atoms resulted in a reduction of frontier orbital energy levels of the polymers.The HOMO/LUMO energy levels of DPP-2ClTT and IID-2ClTT were-5.35/-3.66 eV and-5.88/-3.73 eV,respectively.The charge transport properties of DPP-2ClTT and IID-2ClTT were characterized by top gate/bottom contact(TG/BC)organic thin-film transistors(OTFTs).Due to the favourable HOMO and LUMO energy levels,as well as the well delocalized HOMO and LUMO orbitals,DPP-2ClTT exhibited ambipolar transport characteristics in OTFT devices with the highest electron and hole mobilities of up to 1.36 and 0.89 cm^(2)/V/s,respectively.However,owing to the deep-positioned HOMO energy level and relatively localized HOMO orbitals,IID-2ClTT displayed n-type transport characteristics in OTFT devices with the h

关 键 词：共轭聚合物 直接芳基化缩聚 噻吩衍生物 载流子迁移率 有机薄膜晶体管 

分 类 号：TQ317[化学工程—高聚物工业]