氧化铑电致变色薄膜的制备、结构及性能

采用溶胶_凝胶方法在ITO导电基底上制备氧化铑电致变色薄膜 .当在碱性溶液中对薄膜分别施加阴极和阳极电位时 ,薄膜即呈现由亮黄到深绿的可逆变化 .采用原位XRD、TG_DTA、IR、XPS等方法对薄膜的结晶态、热处理过程以及膜的化学组成进行分析 .应用交流阻抗法计算了薄膜变色过程的扩散系数 ,结果表明该膜基本可以用于变色器件     

盘状多酸P_5W_(30)/阳离子聚电解质/氧化石墨烯杂化多层膜的电致变色性能

为了提高薄膜[PEI/P_5W_(30)]_(30)的电致变色性能,将具有大的二维尺寸和良好导电性的氧化石墨烯引入该薄膜中。通过层层自组装(LBL)技术构筑了基于盘状多酸K12.5Nal.5[Na P_5W_(30)O_(110)]·15H_2O(P_5W_(30))、氧化石墨烯(GO)的复合薄膜[PEI/P_5W_(30)/PEI/GO]_(30)(PEI:聚乙烯亚胺),并利用UV-Vis光谱对薄膜的组成及增长进行监测;通过原子力显微镜对薄膜的表面形貌进行考察,利用循环伏安法对薄膜电化学氧化还原性质进行研究;薄膜在外加氧化还原电位下呈现出无色/蓝色的可逆变化,电致变色响应时间在10 s以内;此外,薄膜在阶跃电位0.75 V/-0.75 V下循环150次,电致变色性能没有明显减弱,体现了薄膜良好的电致变色可逆性。氧化石墨烯的引入使薄膜[PEI/P_5W_(30)/PEI/GO]_(30)呈现出响应速度快、抗电疲劳强的电致变色性能,将在电致变色器件领域有广阔的应用前景。     

NiOxHy薄膜的电致变色特性和机理

运用循环伏安和阶跃电位方法研究了Ni（OH）2粉末靶直流溅射沉积的NiOxHy薄膜电致变色特性．结合实时的光透射-时间变化，发现着色后的薄膜在零外电势下有一自发的消色过程，该过程可能对应着Li 的自发注入。着色没有自发过程，获取了着消色状态Ni2p3／2和O1s的XPS谱，表明在着色态镍被氧化，消色态镍被还原，相应地氧的化学环境发生改变．     

原位聚合沉积聚苯胺薄膜及其电致变色性能

采用原位聚合的方法,以水溶性高分子聚乙烯吡咯烷酮(PVP)为空间稳定剂,直接在玻璃基体表面聚合沉积导电聚苯胺(PANI)薄膜。用扫描电镜(SEM)、紫外可见光谱(UV-Vis)、四探针电导率测试仪和热重分析仪(TG)对聚苯胺膜结构及性能进行了表征。采用循环伏安法测试了薄膜的电致变色性。结果表明:盐酸掺杂聚苯胺薄膜呈翠绿色,薄膜厚115 nm,表面电导率为4.6×10-3S/cm。电致变色实验中聚苯胺电极电位在-6~ 6 V循环变化时,薄膜颜色在黄绿和蓝绿间可逆变化。电致变色前后聚苯胺薄膜的紫外可见吸收光谱表明,随着电极电位的降低,极化子峰发生红移,说明聚苯胺分子链中醌式结构单元被还原,聚苯胺薄膜质子化程度提高。     

聚苯胺电致变色薄膜在不同颜色区间的电化学循环稳定性研究

本文采用电位阶跃和循环伏安法结合紫外可见光光度法研究了聚苯胺薄膜的电致变色性质. 聚苯胺薄膜颜色多变,颜色在浅黄色到绿色再到蓝色之间变化,本文研究在不同的颜色变化区间内聚苯胺薄膜的电化学循环稳定性. 研究结果表明,薄膜在黄色到蓝色(0.4 V ~ 1.2 V)以及绿色到蓝色(0.8 V ~ 1.2 V)区间变化时,电致变色循环性能较差,而在黄色和绿色(0.4 V ~ 0.8 V)之间变化时循环稳定性能良好,着色时间为4.5 s,着色效率高达159.48 cm²·C^-1.     

纳米TiO2膜负载聚(3-溴噻吩)的电化学聚合和电色效应研究

本文以纳米多孔的TiO2膜为基底,通过恒电流阳极聚合的方法制备聚(3-溴噻吩) (PBrT)膜,并研究负载在纳米TiO2膜上PBrT的电致变色性能。采用原子力显微镜(AFM)对纳米TiO2膜的形貌进行表征。利用紫外吸收光谱、计时安培法、计时吸收法研究PBrT膜的电致变色性能。结果显示,沉积在纳米多孔TiO2膜上的PBrT具有更优越的电致变色性能。PBrT膜氧化态时为亮红色,还原态时为深蓝色,颜色的对比度为22%,库仑效率为70%,着色效率为191.3 cm2 C-1（还原态）,88.9 cm2 C-1（氧化态）,该聚合膜具有良好的记忆效应。PBrT/TiO2优异的电致变色性能使其成为良好的电致变色材料,在电致变色器件方面具有潜在的应用价值。     

聚苯胺电致变色薄膜的红外发射特性研究

为实现聚苯胺电致变色薄膜红外发射率的大幅度调制,在柔性PET-ITO薄膜基底上恒电位沉积硫酸-磺基水杨酸共掺杂的聚苯胺薄膜.采用扫描电镜和傅立叶红外光谱仪表征了薄膜的形貌和结构,用红外比辐射率测试仪和紫外-可见分光光度计测量薄膜的红外发射率和可见光透过率.在优化电解液浓度配比的基础上,通过建立薄膜红外发射率与方块电阻之间的关系曲线(R-E曲线),深入探讨了影响聚苯胺红外发射特性的关键因素.研究结果表明,在薄膜中聚苯胺厚度和电导率的影响下,红外发射率和方块电阻之间遵循对数函数的变化特征.随着中间态发射率E0的增加,氧化态和还原态的红外发射率呈阶梯状上升,红外发射率调制幅度ΔE先增大后减小,在0.71处达到最大值.同时,红外发射率调节对薄膜的可见光电致变色性能无消极影响,可见光平均透过率之差可达43.8%.     

多色显示电致变色聚合物叠层复合薄膜的可控制备

在氧化铟锡透明导电玻璃(ITO)电极上电化学聚合依次得到聚4,4',4″-三[4-(2-联噻吩基)苯基]胺(PTBTPA)和聚3,4-乙烯二氧噻吩(PEDOT)薄膜, 从而可控制备出叠层复合薄膜. 由红外光谱(FTIR)和场发射扫描电镜(SEM)表征了复合薄膜. 紫外-可见吸收光谱和电化学测试结果表明, 相对于PTBTPA薄膜(中性态橙色到氧化态深灰色)与PEDOT薄膜(中性态深蓝色到氧化态浅蓝色)的颜色变化, 叠层复合薄膜在不同的电压下能够展现出从橙色→蓝色→墨绿色的颜色变化, 并保持了较好的电化学活性和光学对比度. 这主要源于中性态吸收光谱和颜色显示互补的电致变色材料的选择. 本文提供了一种简单有效的制备多色乃至全色显示的电致变色材料的方法, 该方法同样适用于其它聚合物电致变色材料体系.     

MoO_3电致变色薄膜的XPS研究

近年来 ,随着人们提倡节能和使用洁净能源 ,无机电致变色材料在建筑物采光控制系统和反射率可调表面的应用研究 ,已成为材料领域的一个新热点 .WO3、 MoO3等过渡金属氧化物薄膜具有良好的电致变色效应 ,是人们研究的重点 .其中 MoO3的电致变色效果要好于 IrO2、 TiOx、 CoO及 NiOx等电致变色材料 [1],而且它在可见光区有比 WO3更柔和的色彩 ,使人眼更易于适应其颜色变化 .着色态的 MoO3称为钼青铜 ,其开路记忆也好于钨青铜 [2].故 MoO3电致变色薄膜是极有潜力用于实用化的电致变色器件 .MoO3薄膜常用的制备方法有真空蒸 发、化学气…     

苯胺四聚体薄膜的制备及其电致变色性能

以苯胺四聚体做为电致变色材料, 在保持ITO有效涂覆面积不变的情况下, 通过控制溶液浓度和用量的方式控制膜厚, 采用自然铺展的方式制备得到了均匀的电致变色膜. 循环伏安特性曲线表明, 在－0.2～0.8 V电压范围内, 随着电压的升高, 苯胺四聚体结构发生从还原态到中间态再到氧化态的转变, 并伴随着颜色从浅黄色到绿色再到蓝色的变化. 研究发现, 电解质溶液种类和膜厚对苯胺四聚体膜的电致变色性能有较大影响. 苯胺四聚体膜的对比度按照HCl, HNO₃, H₂SO₄, LiClO₄电解质溶液的顺序依次降低. 随着膜厚度增加, 苯胺四聚体膜的对比度增加, 响应时间延长. 当采用樟脑磺酸掺杂的苯胺四聚体制备电致变色膜时, 在其他条件相同的情况下可以提高苯胺四聚体膜的对比度并同时缩短响应时间.     

Electrochromic Properties of Rhodium Oxide Films Prepared by Sol-gel Method

Electrochromic materials have been extensively investigated for their significant potential in information display, automotive, sensor and smart windows^[1]. Many studies have been carried out on the inorganic electrochromic materials, such as WO₃, MoO₃, NiO_x and so on^[2]. In this paper, We first report the electrochromic behavior of rhodium oxide film prepared by sol-gel method on transparent conductor substrate. The film exhibited reversible two color (from bright yellow to dark green) electrochromic behavior with satisfactory contrast at anodic and cathodic forms when the applied potential was reversed successively.     

Electrochemical deposition of electrochromic niobium oxide films from an acidic solution of niobium peroxo complexes

Deposition of electrochromic niobium(V) oxide films from an acidic solution of niobium peroxo complexes on a transparent conducting cathode in the form of an SnO₂ film on glass was studied. With an increase in the negative potential of the deposition of niobium(V) oxide films from a solution of niobium peroxo complexes at pH 2.5, the structure and composition of the films changed. A study of the electrochromic properties of Nb₂O₅ films revealed broadening of the bands in the electrochromic coloration spectrum with an increase in the negative potential of the deposition.     

Synthesis and characterization of chemically grown electrochromic tungsten oxide

Tungsten oxide thin films, which are cathodic coloration materials that are used in electrochromic devices, were prepared by a chemical growth method and their electrochromic properties were investigated. The thin films of WO₃ were deposited onto electrically conducting substrates: fluorine doped tin oxide coated glass (FTO) with sheet resistance of about 10 Ω/cm. Transparent, uniform and strongly adherent thin film samples of WO₃ were studied for their structural, morphological, optical and electrochromic properties. The XRD data confirmed the monoclinic crystal structure of WO₃ thin films. The direct band gap Eg for the films was found to be 2.95 eV which is good for electrochromic device application. The electrochromism of WO₃ thin film was evaluated in 0.5 M LiClO₄/propylene carbonate for Li⁺ intercalation. Electrochromic properties of WO₃ thin films were studied with the help of Cyclic Voltammetry (CV), Chronoamperometry (CA) and Chronocoulometry (CC) techniques.     

Fabricating polypyrrole/tungsten oxide hybrid based electrochromic devices using different ionic liquids

A facile approach of polypyrrole (PPy)/tungsten oxide (WO₃) composites electrosynthesized in ionic liquids for fabrication of electrochromic devices is discussed. The electrochromic properties of PPy/tungsten oxide nanocomposite films (PPy/WO₃) prepared in the presence of four different ionic liquids, 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIMBF₄), 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF₆), 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI), and 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI) were investigated in detail. Cyclic voltammetry results revealed that PPy/WO₃ nanocomposite films have much more electrochemical activity than those of WO₃ and PPy film. The electrochromic contrast, coloration efficiency, and switching speed of the composite films were determined for electrochromic characteristics. The maximum contrast and the maximum coloration efficiency values were measured as 33.25% and 227.89 cm²/C for the PPy/WO₃/BMIMTFSI composite film. Copyright © 2015 John Wiley & Sons, Ltd.     

Electrochemical and Electrochromic Properties of Ni Oxide Thin Films Prepared by a Sol–Gel Method

Nickel oxide thin films, which are well known anodic coloration materials that are used in electrochromic devices, were prepared by a sol–gel method, and their electrochemical and electrochromic properties were investigated. The sol was prepared from Ni(OH)₂ powder with an average size of 7 nm, in a mixture of ethylene glycol and absolute ethanol. The films were coated on an ITO substrate using the powder, dispersed in the solution. When additive materials, acetyl acetone and glycerol, were added to the sol its hardness and adhesion properties were improved. The optimized thin film formed an amorphous, porous structure, and showed a large current density during continuous potential and pulse potential cycling. The film also was transparent and had a high coloration efficiency (33.5 cm²/C) and a rapid response time (1.0–2.5 s) during the coloring/bleaching process.     

Synthesis and electrochromic properties of polybismaleimides containing triphenylamine units

The bismaleimide (BMI) monomer containing triphenylamine was prepared firstly. Then BMI was reacted with different diamines by Michael addition to obtain prepolymers, respectively. Finally, polyimides (PIs) were obtained through melting procedure. The effects of the structure of BMI moiety and thermal curing condition on thermal stability of PIs were studied by thermogravimetric analysis. PIs have excellent processing properties for film casting. Cyclic voltammetry of PI films was carried out on an indium-doped tin oxide-coated glass substrate. Results which exhibit two reversible oxidations at 0.71–0.78 and 1.06–1.16 V vs Ag/AgCl. The electrochromic performance was investigated by spectroelectrochemical methods. These anodically coloring polymer films not only showed good electrochromic properties but also exhibited high optical contrast ratio of transmittance with a color changing from yellow to green. After 100 cyclic switches, the polymer films still retained excellent redox and electrochromic activity.     

Influence of the crystallinity on the Li+ intercalation process in Nb2O5 films

Nb₂O₅ thin films were prepared by the Pechini method. The effect of the film crystallinity on the electrochemical and electrochromic properties was investigated. A relationship between the crystalline structure and the Li⁺ intercalation/extraction process, stability and kinetics was observed. A significant decrease in the electrochemical response was observed as a function of the number of cycles for films treated at 400 and 450 °C. However, as the calcination temperature increases this effect disappears. XRD studies shown that at 400 °C, the material is amorphous, evolving to orthorhombic phase. The transmittance variation as well as the coloration efficiency increases as the temperature is increased. In the initial cycles the intercalation charge is higher for the amorphous oxide than for the orthorhombic phase. However, the variation in the optical density is small. On the other hand, the charge of the orthorhombic phase oxide does not change. These results suggest that there are two different processes associated with Li⁺ intercalation, but only one of them leads to the coloration process.     

Electrochromic properties of a metallo-supramolecular polymer derived from tetra(2-pyridyl-1,4-pyrazine) ligands integrated in thin multilayer films

The electrochromic behavior of iron complexes derived from tetra-2-pyridyl-1,4-pyrazine (TPPZ) and a hexacyanoferrate species in polyelectrolytic multilayer adsorbed films is described for the first time. This complex macromolecule was deposited onto indium-tin oxide (ITO) substrates via self-assembly, and the morphology of the modified electrodes was studied using atomic force microscopy (AFM), which indicated that the hybrid film containing the polyelectrolyte multilayer and the iron complex was highly homogeneous and was approximately 50 nm thick. The modified electrodes exhibited excellent electrochromic behavior with both intense and persistent coloration as well as a chromatic contrast of approximately 70%. In addition, this system achieved high electrochromic efficiency (over 70 cm(2) C(-1) at 630 nm) and a response time that could be measured in milliseconds. The electrode was cycled more than 10(3) times, indicating excellent stability.