D-A型多色电致变色材料的电化学合成与表征

设计合成了两种新型单体,电化学聚合制得了相应D-A型聚合物:聚{10,13-二(3,4-乙烯二氧噻吩基)二苯并[a,c]吩嗪}(P1)和聚{10,13-二(4-乙基噻吩-2-基)二苯并[a,c]吩嗪}(P2).研究发现,聚合物膜P1在中性态呈现绿色,且随着电压的增加呈现多种不同的颜色,其在1600 nm时最大光学对比度达74.8%,响应时间为0.6 s,着色效率(CE)为285.8cm2/C.聚合物膜P2在氧化态和还原态时分别为灰蓝色和军绿色,也具有较高的光学对比度,快速的转换响应以及较高的着色效率.另外,这两种导电聚合物都具有较低的光学禁带(Eg)(P1为1.26 e V,P2为1.54 e V).本研究提供了两种具有优良性能的电致变色材料,并对其性能参数进行了分析研究.     

Decyloxyphenyl-substituted quinoxaline-embedded conjugated electrochromic polymers with high switching stability and fast response speed

Two novel decyloxyphenylquinoxaline-based donor-acceptor(D-A) electroactive monomers bearing dialkoxythiophene as the donor unit are synthesized using Stille coupling reaction. The corresponding polymers, poly[2,3-bis(4-decyloxyphenyl)-5,8-bis(3,4-dimethoxylthiophen-2-yl)quinoxaline](P1) and poly[2,3-bis(4-decyloxyphenyl)-5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)quinoxaline](P2), are directly deposited onto the working electrode surface by electropolymerization. All materials were characterized by nuclear magnetic resonance(NMR), mass spectrometry(MS), scanning electron microscopy(SEM), cyclic voltammetry(CV), ultraviolet-visible absorption spectrometry(UV-Vis) and spectro-electrochemical measurements. Electrochemical studies demonstrate that both polymers are capable of showing both reasonable n- and p-doping processes, and advanced long-term switching stabilities. 3,4-Ethylenedioxythiophene substituted for 3,4-dimethoxythiophene as a donor unit, which enhances the conjugated double-bond character of the conducting polymer, thus leading to a lower electronic band-gap. Likewise, the neutral state color of the synthesized polymer tuned from blue to blue-green corresponding to the red shift of the maximum absorption wavelengths in the visible region. In addition, kinetics study of P1 revealed 42%(595 nm), 30%(839 nm) and 69%(1500 nm) transmittance changes(ΔT%), while P2 exhibited 32%(740 nm), 71%(2000 nm) at the dominant wavelengths. It was also observed that both films could switch quickly between the neutral state and oxidation state, with the response time less than 1 s both in visible and near infrared regions.