New low-gap polymers from 3,4-ethylenedioxythiophene-bis-substituted electron-poor thiophenes. The roles of thiophene, donor-acceptor alternation, and copolymerization in intrinsic conductivity
New low-gap polymers from 3,4-ethylenedioxythiophene-bis-substituted electron-poor thiophenes. The roles of thiophene, donor-acceptor alternation, and copolymerization in intrinsic conductivity
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DOI：
10.1021/cm049572z
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发表时间：
2004-09-21
影响因子：
8.6
通讯作者：
Zanelli, A
中科院分区：
文献类型：
--
作者：
Berlin, A;Zotti, G;Zanelli, A
以3,4-乙烯二氧噻吩-2,5-取代噻吩[3,4-b]吡嗪（TP）、环戊[2,1-b]为阳极偶联制备了新型低间隙噻吩基规则共聚物；3,4-b']二噻吩-4- 1 （CO）和4-二氰亚甲基- 4h -环五[2,1-b；3、4 b '] dithiophene (CN)。通过循环伏安法、FTIR反射吸收法和紫外可见光谱法、电化学石英晶体微天平分析以及原位p和n电导率测量对共聚物进行了表征。共聚物在0.8-1.3 eV范围内具有较低的光学间隙（在最大吸收时测量）和电化学间隙（从氧化还原电位测量）。基于cn的聚合物显示出最低的电化学间隙（0.8 V）。还制备了CO与3,4-乙烯二氧噻吩（EDT）的无规共聚物，并与相应的规则共聚物进行了比较。随着EDT用量的增加，CO的共聚减少了间隙。从氧化还原电位作为EDT分数的函数的分析中，发现间隙受到单个均聚物的氧化还原电位的限制。通过供体-受体交替，再通过共聚，n掺杂载流子在多噻吩链中的定位逐渐增加，直到期望的本征电导率完全达到p型。
New low-gap thiophene-based regular copolymers are produced by anodic coupling of 3,4-ethylenedioxythiophene-2,5-substituted thieno[3,4-b]pyrazine (TP), cyclopenta[2,1-b;3,4-b']dithiophen-4-one (CO), and 4-dicyanomethylene-4H-cyclopenta[2,1-b;3,4-b']dithiophene (CN). The copolymers are characterized by cyclic voltammetry, FTIR reflection-absorption and UV-vis spectroscopy, electrochemical quartz crystal microbalance analysis, and in situ p- and n-conductivity measurement. The copolymers show low optical gaps (measured at the maximum absorption) and electrochemical gaps (measured from redox potentials) in the range 0.8-1.3 eV. The CN-based polymer displays the lowest reported electrochemical gap (0.8 V). Random copolymers of CO and 3,4-ethylenedioxythiophene (EDT) have also been produced and compared with the relevant regular copolymer. Copolymerization of CO with increasing amounts of EDT decreases the gap. From an analysis of redox potential as a function of EDT fraction, it is found that the gap is limited by the redox potentials of the individual homopolymers. Localization of n-doping carriers in the polythiophene chains is progressively increased by donor-acceptor alternation and then by copolymerization till the expected intrinsic conductivity is made completely p-type.