【作者】 胡彬；

【导师】 张诚； 欧阳密；

【作者基本信息】 浙江工业大学 ， 应用化学， 2013， 博士

【摘要】 吸电子-给电子结构(D-A)电致变色材料因其分子内D基团和A基团之间的电荷转移作用能对其能隙进行调节而成为近几年人们关注和研究的焦点。本论文以噻吩为研究对象,以D-A结构为贯穿全文的线索,考察了侧链吸电子基团的改变、网络状聚合状态、不对称结构设计等分子修饰手段对其电致变色性能的影响。主要目的在于合成多色显示、高光学对比度及快速响应的电致变色材料。本论文首先运用化学法合成了9-(4-苯甲酮基)-咔唑(CPM)、4-((3,6-二噻吩基)-9H-咔唑基)-苯甲酮(TCPM)、4-((3,6-二噻吩基)-9H-咔唑基)-苯甲酸乙酯(ETCB)和4-((3,6-二噻吩基)-9H-咔唑基)-硝基苯(NDTC)四种新单体。该四种单体均具有良好的电化学活性,利用电化学聚合法制备得到相应的聚合物薄膜以及基于ETCB与3,4-乙烯二氧噻吩(EDOT)的共聚物膜。与PCPM相比,噻吩基团的引入提高了聚合物主链的共轭性,降低了聚合物的能隙,使得PTCPM膜具有较多的颜色显示,可以在黄色、棕色、蓝色之间变换。电致变色性能测试结果显示,该膜在近红外区具有较高的光学对比度(41%,1100nm)和较好的响应时间(2s)。另外,PETCB膜可以在黄绿色和紫色之间切换,而PNDTC在中性态下为黄色,掺杂态下转变为灰黑色；PETCB与PNDTC膜的光学对比度和响应时间跟PTCPM膜的性质相似。共聚物P(ETCB/EDOT)膜则呈现了最丰富的颜色,在不同的电压下可实现砖红色、桔红色、黄色、绿色、蓝色五种颜色变换,在1100nm下显示最大的光学对比度(50%),最快响应时间为(1.9s)和最高的着色效率(356.88cm2/C)。该研究结果表明,侧链不同吸电子基团可以导致其相应聚合物的能隙发生变化,从而使其具有不同的颜色显示。主链上窄能隙单体的引入可以进一步增强共轭性,达到改善其性能的作用。文中第二部分合成了具有多个电化学活性点的单体(Z)-2,3-二(4-(3-噻吩)苯基)乙烯腈(Z-TPA)。并运用电化学聚合法制备了聚合物P(Z-TPA)和P(Z-TPA/EDOT)膜。紫外-可见及荧光光谱结果表明单体由于苯乙烯腈结构的存在具有聚集态发光(AIE)的性质。在紫外灯下显示天蓝色。相比于均聚物P(Z-TPA), P(Z-TPA/EDOT)膜具有较好的性能,光谱电化学数据表明共聚物膜在不同电位下不仅能在深红色、灰色、蓝色之间切换,在546nm和1100nm波长下的光学对比度也高达38%和42%,响应时间分别为1.8s和1.9s。另外,基于共聚物薄膜和PEDOT膜的双层器件在560nm和640nm下的光学对比度为18%和22%。响应时间分别为1.5s和2s。该器件还具有较好的稳定性。文中最后部分采用化学法制备了两种基于噻吩衍生物和苯并噻二唑的不对称结构单体4-(2-呋喃)-7-(2-噻吩)-2,1,3-苯并噻二唑(FTBT)和4-(2-呋喃)-7-[2-(3,4-乙烯二氧噻吩))-2,1,3-苯并噻二唑(DFBT),并运用电化学聚合法制备了相应的聚合物薄PFTBT和PDFBT膜。光谱电化学性质测试表明：由于EDOT基团强的给电子特性,PDFBT的最大吸收峰红移。两聚合物的能隙经计算分别为1.63eV和1.42eV。不同的吸收特性使得PFTBT膜在紫色和蓝色之间切换；PDFBT膜在不同的电压下显示蓝绿色和紫黑色的变换。聚合物膜的电致变色性能测试结果显示,PFTBT膜具有较好的电致变色性能,在760和1100nn下的光学对比度分别为35%和45%,相应的响应时间分别为0.9s和1.6s。另外,两种聚合物膜均有较好的稳定性。更多还原

【Abstract】 Donor-acceptor (D-A) electrochromic materials have attracted great interest for the past years due to the fact that their band gap can be tuned through intramolecular charge transfer (ICT) between the donor and acceptor units. In this dissertation, the D-A electrochromic materials based on the thiophene units were developed. The effects of different side-chain accepted groups, networked polymer state, asymmetric structure on the performance of electrochromic materials were investigated. The main purpose was to gain the materials with multicolor-showing、high optical contrast and fast switching time.For the first part, four new electrochromic materials,4-(9H-carbazol-9-yl)-phenyl-methanone (CPM) and4-(3,6-di(thiophen-2-yl)-9H-carbazol-9-yl)-phenyl-methanone (TCPM), ethyl4-(3,6-di(thiophen-2-yl)-9H-carbazol-9-yl)-benzoate (ETCB) and9-(4-nitrophenyl)-3,6-di(thio-phen-2-yl)-9H-carbazole (NDTC), were synthesized and characterized. All the compounds show good electroactivity, and their corresponding polymer could be synthesized by electrochemical route. Moreover, the copolymer based on ETCB and3,4-ethylenedioxythiophene (EDOT) was also obtained by electropolymerization. Compared with the PCPM, PTCPM film shows better performance due to the introduction of the thiophene units, which can show yellow、brown and blue under different potentials and display reasonable optical contrast (41%,1100nm) and faster switching time (2s,1100nm). Moreover, PETCB film displays the color change from yellow-green to blue-purple, while the color-change of PNDTC film is from yellow to gray. Both the polymer films exhibit simlimar optical contrast and switching time with PTCPM. However, the copolymer show better electrochromic properties, which could show five colors change (brick red, orange, yellow, green, blue) under different applied potentials and higher optical contrast (50%of1100nm), faster switching time (1.9s,1100nm) and higher coloration efficiency (356.88cm2C-1,1100nm). All the results show that the band gap of the polymer can be tuned by the acceptor group of the side-chain, which leads to the different colors showing under different applied potentials. The band gap can also be further changed by the introduction of the monomer with narrow bandgap in the main chain, which improve the performance of the polymer.In this second part, a novel material, Z-2,3-bis(4-(thiophen-3-yl)-phenyl)-acrylonitrile (Z-TPA), was synthesized and characterized. Its polymer and copolymer with EDOT were gained by electropolymerization. UV-vis absorption and fluorescence spectra show that this monomer possesses the properties of aggregation-induced emission (AIE) due to the introduction of acrylonitrile unit, which can show sky-blue emitting at the aggregation state and almost no emitting at the solution state. Both its polymer and copolymer displayed better redox activity. Spectroelectrochemical analyses show that the copolymer film exhibited multicolor (from deep red, gray to blue). Spectrochronoamperometry data reveal that the copolymer films have high chromatic contrast (38%in546nm,42%in1100nm) and faster switching time (1.8s of546nm,1.9s of1100nm) as compared to the homopolymer P(Z-TPA). What’s more, the copolymer film was used to construct a dual type polymer electrochromic device (ECDs) with PEDOT. The ECDs shows the reasonable optical contrast (18%in560nm,22%in640nm)、fast switching time (1.5s of560,2s of640nm) and good stability.For the last part, two novel asymmetric-structure compounds based on thiophene derivative and Benzo-2,1,3-thiadiazole,4-(funan-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (FTBT) and4-(2,3-dihydro thieno[3,4-b][1,4]dioxin-5-yl)-7-(furan-2-yl)benzo[c][1,2,5]thiadiazole (DFBT), were synthesized and characterized. Their polymer could be gained by electropolymerization. Spectroelectrochemical analyses show the absorption peaks of PDFBT move to the long-wavelength region due to the existence of EDOT units, the bandgap of PFTBT and PDFBT are1.63and1.42eV, respectively. PFTBT film shows color change from purple to light blue upon different applied potentials and PDFBT film changes from blue-green to black-purple. Spectrochronoamperometry data indicate that PFTBT film exhibits better performance than PDFBT film, which displays the better optical contrast (35%in760nm,45%in1100nm) and faster switching time(0.9s of760nm,1.6s of1100nm). Both the polymer films hold better stability.更多还原