Di-ureasil xerogels containing lithium bis(trifluoromethanesulfonyl)imide for application in solid-state electrochromic devices

In this study we report the characterization of a prototype solid-state electrochromic device based on poly(ethylene oxide) (PEO)/siloxane hybrid networks doped with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The polymer networks prepared, designated as di-ureasils and represented as d-U(2000), were produced by a sol-gel procedure and are composed of a siliceous framework to which both ends of polyether chains containing about 40 CH₂CH₂O units are covalently bonded through urea linkages. Samples with compositions of 200 ≥ n ≥ 0.5 (where n is the molar ratio of CH₂CH₂O to Li⁺) were characterized by thermal analysis, complex impedance measurements and cyclic voltammetry at a gold microelectrode. Electrolyte samples were obtained as self-supporting, transparent, amorphous films and at room temperature the highest conductivity was observed with the d-U(2000)₃₅LiTFSI composition (3.2 × 10⁻⁵ Ω⁻¹ cm⁻¹). We report the results of preliminary evaluation of these polymer electrolytes as multi-functional components in prototype electrochromic displays. Device performance parameters such as coloration efficiency, optical contrast and image stability were also evaluated. The electrolytes with n > 8 presented an optical density above 0.56 and display assemblies exhibited good open-circuit memory and stable electrochromic performances.     

塑料衬底上制备WO3电致变色薄膜及其特性研究

采用真空电子束蒸发低压反应离子镀技术制备WO3电致变色薄膜,对比研究在玻璃衬底和塑料衬底上制备的WO3薄膜的物理特性、电化学特性和电致变色特性。采用扫描电子显微镜、X射线衍射、和电子探针显微分析技术测试了WO3薄膜的表面形貌、晶体结构和成分比例等。采用分光光度计测试了WO3薄膜在原始态、着色态和退色态的透射光谱、透射率变化的时间响应。     

WOx:Mo薄膜的结构及电致变色性能研究

采用反应磁控溅射工艺,以纯钨和纯钼为靶材在ITO玻璃上制备Mo掺杂WOx电致变色薄膜,用薄膜的透射光谱和XRD衍射方法对掺杂后薄膜的电致变色性能和结构进行了分析,研究了Mo掺杂对WOx薄膜电致变色性能和微观结构的影响机理。实验结果表明：在一定掺杂范围内,Mo掺杂对薄膜电致变色性能有较大提高;掺杂越均匀,对薄膜电致变色性能的改善越显著。影响薄膜电致变色性能的相应掺杂量由溅射时间表示,相对掺量存在最佳值,即7．7％附近,薄膜的变色性能可得到最大的提高,按实验结果趋势分析掺杂量存在有效范围,超出有效掺杂范围,掺杂便会失效。XRD分析表明,掺杂Mo之后的WOx薄膜仍为非晶态,且非晶态有增强的趋势。     

WO3/TiO2复合薄膜的制备及其电致变色性能

使用水热法在掺氟SnO₂涂覆的导电玻璃（FTO）基板上生长TiO₂纳米线,随后在TiO₂纳米线上采用水热法生长WO₃纳米线,制备出WO₃/TiO₂复合薄膜。通过循环伏安法（CV）、计时电流法（CA）、计时电量法（CC）等电化学测试技术研究了WO₃/TiO₂复合薄膜的电致变色性能;采用紫外分光光度计对薄膜的着色﹑漂白状态的响应时间进行测试。通过以上测试,计算得到了薄膜的循环稳定性﹑光调制﹑着色效率和切换时间（Y和X）等参数。结果显示WO₃/TiO₂复合薄膜的电致变色性明显提高,其中WO₃/TiO₂复合薄膜可逆性增加了6%,着色效率提高了40.96 cm2/C。      

NiO/PB复合电致变色薄膜的制备及其性能研

采用水热法制备了垂直生长的氧化镍(NiO)纳米片薄膜, 并利用电沉积法将普鲁士蓝(PB)负载到NiO纳米片薄膜上, 制备了新型的NiO/PB复合电致变色薄膜。利用X射线衍射仪(XRD)、场发射扫描电镜(SEM)对样品的晶型以及微观形貌进行了表征, 采用紫外-可见光光度计以及电化学工作站对NiO/PB复合薄膜的电化学和电致变色性能进行了研究和表征。结果表明: NiO/PB复合电致变色薄膜具有多孔结构和较大的比表面积, 可以增大电解质与电极材料的接触面积。PB成功负载到NiO薄膜表面, 使NiO/PB复合薄膜表现出较大的电流密度。相比于单层NiO薄膜, NiO/PB复合薄膜表现出更好的电致变色性能, 其光调制范围可以达到46%, 着色效率为141 cm²/C, 并且其着色时间可以缩短到5 s, 褪色时间为6 s。     

电致变色材料、器件及应用研究进展

电致变色材料具有结构可控、色彩丰富、成本低廉、节能低耗等特点,是目前最具应用前景的智能材料之一。概述了电致变色器件的基本结构、变色机理,着重介绍了电致变色器件各层材料(透明导电层、电致变色层、电解质层、离子储存层)的特性要求及研究现状,举例说明了其在智能窗、防眩目汽车后视镜、电子纸、传感器、军事伪装中的应用。     

非晶态三氧化钼薄膜超低温制备及其电致变色特性研究

在基片温度173K的条件下，采用直流反应磁控溅射法制备MoO3薄膜。运用XRD、SEM、可见分光光度计、伏安特征曲线、拉曼光谱研究分别对薄膜的晶体结构、微观表面形貌、透射光谱特性、电致变色性能及成分进行分析，探讨了MoO3薄膜的电致变色性能和微观结构之间的关系。结果表明，超低温有利于MoO3薄膜非晶化，薄膜表面有较多的孔隙，有利于Li^＋的抽取，进而显示出很好的变色性能，在550nm处着色系数达到了41．6cm^2／c，可见光400-800nm范围内着色态和漂白态平均透光率差值达60％以上。Raman光谱分析发现，在拉曼位移831cm^-1、952cm^-1。处有强的吸收峰，其中831cm^-1处对应于O-Mo^6＋-O的伸缩振动模式，952cm^-1对应于M0^6＋=O的弯曲振动模式。     

聚(联吡啶亚甲基苯乙烯-甲基丙烯酸齐聚氧化乙烯酯)薄膜修饰电极

合成了一种兼具电致变色性能及离子电导性的新型梳型联吡啶聚合物PVSEO_(21)。测试了其修饰热解石墨电极在液体电解质中的循环伏安特性及其电致变色性能。该聚合物具有可逆性好、响应速度快等特点。其高速响应与聚合物本身的离子电导性有关。薄膜厚度为1.85μm时,该聚合物修饰电极在0～—0.8V和—0.8～—1.3V(vs.SCE)之间发生一电子和二电子氧化-还原反应,相应的电致变色响应时间分别为3ms和7ms。     

Solid state electrochromism in WO3

ZrO₂ and Ta₂O₅ films were used as solid electrolyte layers in electrocnromic cells of WO₃. Measurement of the weight changes of those cells during coloration and bleaching suggested that water contained in the cells played an important role for the coloration. Another kind of cell showed that it is not the water in WO₃ layer but that in a solid electrolyte layer that is essential. Reasons of deterioration of the electrochromic cells are not only a peeling Au electrode off from the cells but also a kind of morphologic changes of films.     

Hybrid Copper‐Nanowire–Reduced‐Graphene‐Oxide Coatings: A “Green Solution” Toward Highly Transparent,Highly Conductive,and Flexible Electrodes for (Opto)Electronics

This study reports a novel green chemistry approach to assemble copper‐nanowires/reduced‐graphene‐oxide hybrid coatings onto inorganic and organic supports. Such films are robust and combine sheet resistances (<30 Ω sq^?1) and transparencies in the visible region (transmittance > 70%) that are rivalling those of indium–tin oxide. These electrodes are suitable for flexible electronic applications as they show a sheet resistance change of <4% after 10 000 bending cycles at a bending radius of 1.0 cm, when supported on polyethylene terephthalate foils. Significantly, the wet‐chemistry method involves the preparation of dispersions in environmentally friendly solvents and avoids the use of harmful reagents. Such inks are processed at room temperature on a wide variety of surfaces by spray coating. As a proof‐of‐concept, this study demonstrates the successful use of such coatings as electrodes in high‐performance electrochromic devices. The robustness of the electrodes is demonstrated by performing several tens of thousands of cycles of device operation. These unique conducting coatings hold potential for being exploited as transparent electrodes in numerous optoelectronic applications such as solar cells, light‐emitting diodes, and displays.