ITO／WO3／LiTaO3／NiOx／ITO全固态电致变色器件的制备及性能研究

利用磁控溅射法在不同流量的液氮低温冷却的条件下在ITO玻璃上制备WO3、LiTaO3、NiOx、ITO薄膜,5层薄膜组成ITO/WO3/LiTaO3/NiOx/ITO全固态电致变色器件.采用XRD、SEM、可见光分光光度计等测试手段进行对比分析.结果发现:低温制备的WO3薄膜为非晶态结构,在可见光范围内漂白态和着色态的平均透射率差△T可以达到70%以上.LiTaO3薄膜表面的颗粒度比较小,结构致密,其厚度对整个器件的光学性能有一定影响,在可见光范围内平均透射率达到95%.在低温条件下制备的NiOx薄膜比常温沉积的薄膜会提供更多的Ni2 离子参与变色反应.该器件显示出较好的电致变色特性.     

金属氧化物基电致变色器件的光透特性及其变色机理

在ITO导电玻璃基底上沉积得到WO3薄膜和NiOx薄膜,采用PMMA-LiClO4-PC胶质电解质作为离子电导层,制备得到了三明治式的电致变色(EC)器件.在300～1 000 nm波段的辐照光驱分别测试了器件在互补着色和同时着色时的光透性能.通过分析器件在互补着色和同时着色时的电色反应,给出了不同阶段的电致变色过程的电化学反应机理.特别考虑了实际应用中由于潮解和极化等因素引起的不利化学反应对器件性能的影响,对电致变色器件的实用化具有一定的指导意义.     

ZAO/WO3/PAMPS/ZAO全固态电致变色薄膜器件的制备和性能研究

采用直流反应磁控溅射法制备ZAO薄膜和WO3薄膜,PAMPSS-Li 作为离子储存层和离子导电层,ZAO薄膜作为对电极,制备成ZAO/WO3/PAMPS/ZAO电致变色器件.运用XRD、SEM、可见分光光度计、伏安特征曲线分别对薄膜的晶体结构、成分、微观表面形貌、透射光谱特性及电致变色性能进行分析,探讨了WO3薄膜的电致变色性能和微观结构之间的关系.结果表明:PAMPS-Li 离子胶体是一种很好的离子储存层和离子导电层.实验中全固态电致变色薄膜器件在可见光范围内着色态和褪色态平均透光率差值高达50%以上.     

电致变色器件中WO3薄膜高温环境性能退化机理

目的研究ITO/WO_3/LiTaO_3/NiO_x/Al反射式无机全固态薄膜中WO_3薄膜在高温环境中的性能退化机理。方法采用直流反应磁控溅射法制备电致变色器件和WO_3单层薄膜,并进行高温加热试验。对电致变色整体器件进行反射率变化量的测试,对WO_3薄膜进行微观结构分析和电化学循环特性分析。结果电致变色器件经不同温度加热后,350℃以下,反射率变化量下降不明显,350℃以上反射率变化量明显降低,WO_3薄膜发生了非晶结构向晶体结构的转变。WO_3薄膜的电化学循环特性为:随着加热温度的升高,电致变色响应时间增大,350℃以上,响应时间急剧增大,电致变色性能降低明显,但电致变色循环稳定性更好。结论 WO_3薄膜疏松多孔的非晶结构能提供更多的离子(电子)注入和传输通道,电致变色性能更好,但疏松多孔结构循环稳定性较差。致密的晶体结构因通道闭合,离子(电子)不易注入和传输,电致变色性能较差,但致密结构循环稳定性较好。     

溶胶-凝胶法制备NiO薄膜

采用溶胶-凝胶技术制备了NiO薄膜,并利用热重分析法、X射线光电子光谱法、X射线衍射法对其进行分析,同时用紫外线光谱法研究了电致变色特性.实验结果表明溶胶-凝胶法是1种制备NiO薄膜的有效方法,薄膜的成分很大程度上取决于热处理的温度,450℃时电致变色的效率为最佳.     

化学溶液沉积法制备WO3•2H2O薄膜及其电致变色性能

目的研究具有不同微观结构的WO_3·2H_2O薄膜的电致变色性能。方法采用化学溶液沉积法在FTO玻璃上制备WO_3·2H_2O薄膜,通过加入不同的形貌控制剂(柠檬酸或草酸铵),制备不同纳米结构的WO_3·2H_2O薄膜。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)分析薄膜的成分结构和微观形貌,利用紫外可见光分光光度计对薄膜在波长为200～1000nm范围内的透光性进行研究,并通过电化学工作站对薄膜进行电化学性能分析。结果采用柠檬酸作为形貌控制剂制备的WO_3·2H_2O薄膜的透光性高达82%左右,其在着色和褪色状态的透过率差值为36.2%。通过添加柠檬酸或草酸铵作为形貌控制剂制备的WO_3·2H_2O薄膜均呈现出纳米片状结构,纳米片的厚度分别为5～15 nm和50～60 nm,但是采用柠檬酸制备的WO_3·2H_2O具有较多的间隙和裂缝,使其表现出了较好的电致变色性能。结论具有间隙和裂缝的纳米WO_3·2H_2O薄膜增加了薄膜与电解质的接触面积,减少了离子扩散的路径距离,更小的纳米结构可以提供更多的化学活性位点,从而表现出较好的电致变色性能。     

无机复合纳米材料电致变色薄膜研究进展

开发循环稳定性好,着/褪色响应快,变色效率高的薄膜是电致变色材料的研究重点。与有机材料相比,无机材料的稳定性更强,实用性更好。通过构筑高孔隙率、低电阻率、大比表面积和多活性位点的微纳结构活性薄膜,能有效提高电致变色性能。本文阐述了电致变色器件的变色原理,详细介绍了介孔结构、纳米阵列结构及核壳结构等特殊微纳结构无机电致变色薄膜的性能优势和发展现状,进而探讨了微纳结构薄膜存在的瓶颈问题和发展趋势,有利于精准拓展研究思路,对推动无机电致变材料的发展与应用具有指导作用。     

锶离子掺杂对NiO薄膜离子传输和电致变色性能的改善作用

电致变色材料在智能显示和军事伪装等领域具有非常重要的应用前景。为了改善NiO薄膜在碱性电解液中变色响应时间长,循环稳定性差的问题,本文采用水热法制备了锶离子掺杂纳米片状NiO电致变色薄膜,离子掺杂引起的晶格畸变与微纳结构的协同作用,使NiO薄膜展现出了优异的电致变色性能。锶离子掺杂一方面改善了NiO薄膜的电化学特性,从而缩短了电致变色响应时间(着色时间约为4.5 s,褪色时间约为2.7 s),提高了着色效率(CE, 85.2 cm₂^C_-1⁾。另一方面为NiO晶体结构提供了支撑,增强了电致变色过程中晶体结构的稳定性,从而显著提升了薄膜的循环稳定性(循环次数超过了10000次)。本文的研究结果对促进电致变色材料的工程化应用具有一定的借鉴和指导意义。     

La、Nd、Bi共掺杂制备TiO2电致变色薄膜及其性能研究

为了提高TiO2薄膜的光学属性和着色效率,采用溶胶-凝胶工艺,以钛酸丁酯为前驱体在ITO导电玻璃基片表面制备了La、Nd、Bi共掺杂TiO2薄膜。采用XRD、UV-vis和化学工作站等手段研究了TiO2薄膜的结构和表面的光学和电致变色性能。结果表明:在400、500和600℃热处理的二氧化钛干凝胶中形成锐钛矿型二氧化钛,且热处理温度越高,晶体发育越完整。La、Nd、Bi掺杂TiO2增加了TiO2八面体的排列无序性,导致非晶化程度提高。体积分数为12%的钛酸丁酯相应制备的薄膜具有优良的电致变色性能。500℃热处理的TiO2薄膜电致变色性能最为优异。实验进行了La、Nd、Bi单独掺杂TiO2薄膜的性能分析,单独掺杂摩尔分数为8%La、18%Nd、6%Bi的TiO2薄膜具有较优异的变色性能,单独掺杂变色效果的顺序是6%Bi<8%La<18%Nd。La、Nd、Bi共掺杂锐钛矿型TiO2仍然具有很高的非晶化程度,且当掺杂摩尔比La:Nd:Bi=4:10:2时,取得薄膜最佳循环伏安特性,掺杂TiO2非晶化程度最高。     

掺氮对WO_3薄膜电致变色调制性能的影响

采用反应磁控溅射法在ITO玻璃上制备氮掺杂氧化钨(WO3:N)薄膜。采用XRD、XPS、AFM对薄膜的结构、成分、结合键和表面形貌进行表征。将WO3:N薄膜封装制成电致变色器件,并采用直流稳压电源和分光光度计对其进行变色调制性能测试。结果表明:制备的WO3:N薄膜为纳米晶结构,其衍射峰位随着含N量的增加而右移;WO3:N薄膜中W、O分别以W6+和O2-存在,而N以中性价态、WO3中的O位替换以及表面吸附3种状态存在;随着WO3:N薄膜中含N量的升高,表面粗糙度逐渐增大,且有利于器件着色;当掺氮2.80%(摩尔分数)时,电致变色器件调制幅度最大为68.8%,比未掺氮器件的高出7.7%,适用于节能玻璃。     

New functionalized 3-(alkyl)thiophene derivatives and spectroelectrochemical characterization of its polymers

Three novel 3-[ω-(p-methoxyphenoxy)alkyl]thiophene monomers were synthesized and electrochemically polymerized on ITO electrodes by potentiodynamic or potentiostatic methods. Potentiostatic deposition provided films with better stabilities and had smaller quantities of soluble oligomers formed during polymerization. We also observed that derivatives with shorter alkyl chains in the substituted thiophene are difficult to polymerize by electrochemical methods. Spectroelectrochemical characterization of the polymer films obtained showed that their colors depend on the alkyl chain length in the substituted monomer. This demonstrates that the electrochromic behavior of these polymers can be tailored by means of the chemical synthesis of the monomers. The electrochromic properties presented by these new polymers motivate their future application in electrochromic devices.     

High-resolution electron microscopy analysis of microstructural changes in WOx electrochromic films

The microstructural changes in WO_x electrochromic (EC) films of bleached and colored states have been studied by high-resolution electron microscopy (HREM) analysis. The results reveal that drastic changes in microstructure occur during the coloring process of WO_x EC films. Although X-ray diffraction analysis indicates that the phase changes of a WO_x film are reversible between its bleached and colored state, HREM analysis shows that the microstructural change in such films is an irreversible process.     

基于光固化的全固态电致变色器件制备与性能

目的使用聚乙二醇400(Polyethylene Glycol 400,PEG400)掺杂直接将光固化树脂溶于电解液,并通过光固化先液后固制备全固态电解质。方法使用溶胶-凝胶法制备掺杂了聚乙二醇400的WO_3薄膜,用高氯酸锂粉末、聚碳酸酯(Polycarbonate,PC)、聚甲基丙烯酸甲酯(Polymethyl Methacrylate,PMMA)粉末和光固化树脂(UV-cured resin)配制了凝胶态的电解液。采用毛细封装法对制得的WO_3薄膜进行光固化封装。对制得的电致变色器件进行循环响应时间、光透过率和记忆效应测试,使用扫描电子显微镜对薄膜表面形貌进行分析。结果掺杂了聚乙二醇400的WO_3薄膜表面裂痕明显减少,平均粗糙度为3nm,疏松孔隙结构较多,制得的电致变色器件完全着色时只需要0.5s,而未掺杂PEG400制得的电致变色器件完全着色需要4 s,掺杂了PEG400制得的器件完褪色需要0.5 s,而未掺杂的器件需要1.5 s,且掺杂组比未掺杂组的光调制幅度要高出20%,记忆效应也要更好。结论掺杂PEG400可以使WO_3薄膜表面更加均匀,有效地提升了光调制幅度和降低了循环响应时间,记忆效应也有明显的提升。同时,利用光固化技术制备全固态电致变色器件,制备工艺简单,且易于保存。     

Study and development of conducting polymer-based electrochromic display devices

The electrochromic response of conducting polypyrrole (PPy)/Prussian blue (PB) and conducting polyaniline (PANI)/Prussian blue (PB) composite films has been studied in different electrolytes such as KCl, LiClO₄, K₂SO₄, KNO₃, KI/I₂, etc. by depositing the PB films on top of the conducting PPy and PANI films—all prepared by electrochemical methods. The results show that the use of PB on PPy and PANI not only yields high contrast but also extends the electrochromic response to a wider region of the visible spectrum, thus working as a sensitizer for improving the electrochromic response of the conducting PPy and PANI. These electrochromic films have been characterized by other physicochemical characterization techniques such as cyclic voltammetry, SEM, XPS, XRD, etc. The electrochromic behaviour of the PPy/PB composite system has been described in detail. Electrochromic display devices using solid polymer electrolytes, which are directly useful for commercial production of such devices are currently under study.     

Comparative studies on Langmuir–Schaefer films of polyanilines

Langmuir isotherms of polyaniline (PANI), poly(o-toluidine) (POT), poly(o-anisidine) (POAS) and poly(o-ethoxy aniline) (PEOA) were investigated at aqueous subphase of pH 1, where doping during monolayer formation appeared as an essential step for high quality of the film. The effect of substituent groups in polyanilines plays a prominent role for the formation of Langmuir films. The area per unit repeat molecule was shown to increase by an increment of the substituent groups in polyanilines. Ultra-thin films of PANI, POT, POAS and PEOA were engineered by Langmuir–Schaefer (LS) technique. The uniformity of the deposited polyanilines LS films was verified by atomic force microscopy (AFM). The electrochemical properties of polyanilines LS films were investigated by cyclic voltammetry and current transient measurements, and the electrical characteristics were investigated by depositing the films on interdigitated electrodes. The electrochromic switching response time and diffusion coefficient of such LS films were also estimated by electrochemical surveyings.     

柔性衬底WOx-Mo薄膜电致变色性能研究

采用射频磁控溅射工艺,在镀有ITO薄膜的柔性PET衬底上低温制备WOx-Mo薄膜,利用电化学工作站测试薄膜的循环伏安曲线和计时电流曲线来分析薄膜的电致变色性能.结果表明:随Mo掺杂量的增加,薄膜的氧化峰峰位往电压正方向移动,并且氧化峰电流峰值增加,薄膜着色响应时间缩短,退色时间延长.当Mo掺杂量为15.4%时,着色时间最短达到4.53 s,退色时间最长达到9.8 s.薄膜的可逆性与电荷在薄膜中的滞留量有关,在Mo掺杂量为7.6%时,薄膜可逆性最好,达到51.2%左右,电荷滞留量为2.4E-3C.     

Electrochromism of poly(3,4-ethylenedioxythiophene) films on Au nano-brush electrode

Au nano-brush membranes were prepared using a modified template method. Poly(3,4-ethylenedioxythiophene) (PEDOT) films were immobilized by an electropolymerization with the product membrane as the working electrode. The PEDOT film on the nano-brush electrode showed higher electrochromic (EC) coloration compared to the PEDOT film on an Au planar electrode.