A dual electrochromic film based on nanocomposite of aniline and o-toluidine copolymer with tungsten oxide nanoparticles

A dual electrochromic (EC) film was prepared based on composite of tungsten oxide nanoparticles and copolymer of aniline and o-toluidine, by electrochemical polymerization method. In this method, aniline and o-toluidine monomers were dispersed in the solution containing tungsten oxide (WO₃) nanoparticles and the final mixture was used for electrodeposition of film on fluorine doped tin oxide (FTO) coated glass. WO₃ nanoparticles were incorporated in the copolymer matrix structure, and a dual EC film was constructed. EC properties of WO₃, copolymer and WO₃-copolymer nanocomposite films were evaluated by cyclic voltammetry (CV) and the UV–Vis spectrophotometry. Also, the optical response and coloration efficiency (CE) of samples were investigated. The composition of organic-inorganic EC materials have improved properties in application of the EC film such as significant optical modulation (37.35% at 633 nm) and high switching speed and high coloration efficiency (116.6 cm² C⁻¹ at 633 nm). These achievements were better than WO₃ or copolymer films. The improved EC properties were appertained to the mixture of prominences of both materials.     

A new multicolored and near-infrared electrochromic material based on triphenylamine-containing poly(3,4-dithienylpyrrole)

A new compound containing both 3,4-dithienylpyrrole (DTP) and triphenylamine (TPA) groups, namely, 4′-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-N,N-diphenylbiphenyl-4-amine (DTP-Ph-TPA), was designed and synthesized. The polymer poly-DTP-Ph-TPA (PDTP-Ph-TPA) was prepared by electropolymerization from DTP-Ph-TPA. When the applied potential circulates from 0.0 V to 1.4 V, the polymer not only exhibits reversible multicolor in the visible region (yellow, light green, magenta and blue), but also shows excellent electrochromic properties in the NIR region with high contrast ratio (ΔT = 70.5% in 1550 nm, ΔT = 67.9% in 1310 nm) and a very short response time (about 1.4 s for 1550 nm, 0.9 s for 1310 nm). A single layer electrochromic device (ECD) based on polymer PDTP-Ph-TPA was constructed and characterized.     

An ambipolar low band gap material based on BODIPY and EDOT

A novel donor–acceptor type conducting polymer based on BODIPY dye as acceptor and EDOT units as donor parts is synthesized electrochemically. The unique combination of BODIPY and EDOT units provides an ambipolar (n- and p-doping processes) low band gap material (4). This is the first example of p–n junction in an organic π-conjugated material where BODIPY unit is incorporated directly in the main chain. Furthermore, the polymer film exhibits electrochromic behavior upon p-doping: a color change from light violet (neutral) to indigo (oxidized).     

Anodic iridium oxide films: A new electrochromic

We review the preparation and properties of a new electrochromic material, an anodically grown iridium oxide film (AIROF), and describe three new developments: 1) a heat treatment which improves response times and greatly improves stability; 2) the observation that the maximum coloration and the speed of response are independent of pH, i.e., essentially the same for acidic, neutral, or alkaline electrolytes, and 3) the development of a transmission device in which the AIROF is grown on a semitransparent conducting substrate. We have also observed a new electrochromism isotherm in AIROF's, and shown that there are two distinct electrochromic processes with different isotherms. Since the two distinct processes cannot both be simple proton injection, our results show clearly that other processes can accomplish coloration in AIROF's. Moreover, both isotherms are dominated by internal entropy changes of noninteracting particles. Such isotherms are qualitatively different from that of the proton-injection process in WO3electrochromics.     

A new p- and n-dopable selenophene derivative and its electrochromic properties

A novel electrically conducting polymer, poly(2-dodecyl-4,7-di(selenophen-2-yl)benzotriazole) (PSBT), containing selenophene as the strong donor and benzotriazole as the strong acceptor groups was synthesized by electrochemical polymerization. Homopolymerization and copolymerization (in the presence of 3,4-ethylenedioxythiophene (EDOT)) were achieved in acetonitrile/dichloromethane(95/5 v/v) with 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF₆). The electrochemical and optical properties of homopolymer and copolymer were investigated by cyclic voltammetry, UV–Vis, near IR Spectroscopy. Cyclic voltammetry and spectroelectrochemistry studies demonstrated that homopolymer can be reversibly reduced and oxidized (both n- and p-doped) between ?1.9 V and +1.4 V, at a scan rate of 100 mV/s. The homopolymer revealed a transmissive light blue color in the oxidized state, and a red-purple color in the neutral state. A transmissive light blue color was also observed in the reduced state. Homopolymer films could be fully switched between their reduced and oxidized forms in 2.4 s and 0.4 s with a percent transmittance of 32% and 56% at 511 and 1200 nm, respectively. Poly(SBT) exhibits a λ_max value of 511 nm and a band gap of 1.67 eV which is quite low among the selenophene-containing polymers reported so far except for poly(1,2-bis(2-seleninyl)ethane).     

Solvent resistant electrochromic polymer based on methylene-bridged arylamines

We here report the synthesis and the electrochemical, spectroelectrochemical and FT-IR characterization of a novel arylamine electrochromic film. The electron-donating fragments are isolated tetraphenylbenzidine (TPB) groups. The special configuration that perpendicularly binds the triphenylamine units by a tetrahedral carbon prevents orbital interactions between redox fragments and localizes the generated radicals, rendering an efficient electropolymerization process. The polymer film obtained showed reversible electrochemical oxidation accompanied by strong and long-lasting color changes and high insolubility in most solvents once electrodeposited on the electrode surface. We propose a plausible electropolymerization mechanism on the basis of the FT-IR spectra.     

A new blue light emitting and electrochromic polyfluorene derivative for display applications

A novel blue emitting and electro-chromic conjugated copolymer based on 9,9′dioctylfluorene (F8) and spiro(fluorene-9,9′-xanthene) (SFX) has been prepared. Optical, photophysical and electrochemical characterizations are given for the synthesized polymer; poly[spirofluorene-co-9,9′dioctylfluorene] P(F8-SFX). Switching of the corresponding polymer between yellow and purple states is demonstrated, and blue emission with Commission Internationale de L’Eclairage (CIE) coordinate at (0.19, 0.15) is obtained from PLED device. The addition of a thin polymer interlayer ((F8)_0.5–(TFB)_0.5) is further investigated to maintain color purity. Furthermore, all polymer electrochromic device (ECD) based on P(F8-SFX) and poly(ethylene dioxythiophene) (PEDOT) was constructed. Spectroelectrochemistry and switching ability of the device were also investigated by UV–vis spectroscopy.     

反射型聚苯胺基柔性电致变色器件的研制

采用循环扫描伏安法在Au/Cr/PET复合基底上聚合出聚苯胺(PAN)膜,设计并制备了基于PAN的反射型柔性电致变色器件(ECD)。研究了该ECD反射光谱的电压响应特性。结果显示,所得PAN具有晶体结构,微观上呈直径约60nm的纤维网形态,与Au/Cr/PET基底结合良好;该ECD的反射光谱曲线的波长选择性,在-0.4～+1.8V电压范围内随电压增加而逐渐明显,反射率峰值出现的位置由476nm移至584nm,表现出良好的电致变色响应特性。     

聚苯胺基柔性电致变色器件的设计与研制

采用循环扫描伏安法在导电聚酯薄膜上聚合出聚苯胺(PAN)膜,考察了PAN膜的聚合过程及其表现出的电致变色行为;设计并制备了基于PAN膜的反射型柔性电致变色器件,考察了该器件反射光谱的电压响应特性.结果表明,电聚合过程中,在-0.2～2.0V电压范围内,PAN膜的颜色在黄绿-绿-深蓝之间循环变化;在-0.4v～1.8v电压范围内,研制的基于PAN膜的反射型柔性电致变色器件的反射率及其峰值随着外加电压的改变而变化,表现出较好的电压响应特性.     

Highly contrasted and stable electrochromic device based on well-matched viologen and triphenylamine

An electrochromic device (ECD) can change color absorption when subjected to an appropriate voltage. Such a device includes three components: a working electrode, a counter electrode and an electrolyte. Compatibility of these three components is important for ECD’s stability. In this study, two novel compatible electrochromic materials, cathodic 1-(9-hexyl-9H-carbazole)-1′-(propylphosphonic acid)-4,4′-bipyridilium dichloride and anodic (4-(diphenylamino)phenyl)methylphosphonic acid were designed, synthesized and fabricated into electrochromic electrodes using a chemisorption method. We characterized the electrochromic performance of these two electrodes, including the degree of color change, color changing voltage and charge capacity; the results indicated that they matched each other very well. An electrochromic device fabricated using these two electrodes, as expected, exhibited rapid, vivid color changes and proved highly stable for up to 100,000 cycles.     

全固态聚苯胺-二氧化钛电致变色器件的制备

以聚苯胺(PANI)为电致变色材料,分别制备了对称结构(SSECD,ITO‖PANI‖解质‖PANI‖lTO)和非对称结构(ASECD,ITO‖PANI‖电解质‖TiO<,2>‖ITO)的全固态电致变色器件.TO<,2>薄膜的制备采用提拉法.经500℃处理后得到锐钛矿结构,所得薄膜由粒径10-20 nm的TiO<,2>...     

Electrochemical synthesis and electrochromic application of a novel polymer based on carbazole

The compound containing carbazole and thiophene, named as B1 was synthesized with 4-(9H-carbazol-9-yl) phenol and 3,4-dibromo thiophene. Additionally, the electrochemical polymer of B1 was synthesized and coated onto an ITO-glass surface via electrochemical oxidative polymerization. The electrochemical synthesis of the polymer was performed both in 0.05 M LiClO₄ supporting electrolyte in AN/BF₃EtE (1:1, v/v) and an AN/LiClO₄ solvent/electrolyte solution. The compounds were characterized by FT-IR and NMR techniques. The spectroelectrochemical and electrochromic properties of this polymer were also investigated for two electrolyte solution systems. The switching ability of this polymer was measured as the percent transmittance (%T) at its point of maximum contrast. According to the electrochromic measurements, the synthesized polymer had a blue color when it was oxidized, and also when it was reduced, it had a transparent color. Additionally, redox stability measurements indicates that the polymer had a high stability and it could be used to produce new polymeric electrochromic devices and also, it was a good candidate for electrochromic devices (ECDs) applications.     

Design of highly stable and solution-processable electrochromic devices based on PEDOT:PSS

This study aimed to improve the repeatability of electrochromic devices(ECD) based on Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS); therefore, ferrocene was introduced as an anodic species. When 0.05 wt% ferrocene as compared to that of the electrolyte was contained in the electrolyte layer, the bleaching time significantly reduced from 110 s to 25 s without changing ΔT; consequently, repeatability markedly improved. However, ferrocenium cations, generated when ferrocene undergoes a reversible redox reaction, have high reactivity with oxygen, and hence, the stability of ECD is lowered over time. To overcome this problem, l-ascorbic acid, commonly known as vitamin C, was introduced as an antioxidant in the electrolyte layer. The repeatability of the ECD and the storage stability of the electrolyte solution were improved without side effects at an l-ascorbic acid ratio of 0.025 wt% as compared to that of the electrolyte. In addition, using cyclic voltammetry, it was confirmed that l-ascorbic acid did not affect the electrochemical properties of the ECD, and played only the role of an antioxidant for ferrocene. Furthermore, regarding encapsulated ECD, high repeatability could be maintained by preventing solvent evaporation and oxygen penetration into the electrolyte layer. When ECD of size 4 cm × 5 cm was glass encapsulated, there was no change in ΔT even after 5000 cycles for 139 h. We observed day-to-day changes in the response time and ΔT for 30 d; it maintained almost constant values from the beginning. Repeatability tests of 15 cm × 15 cm size large-area ECD for applications, such as smart windows, were conducted.     

Hybrid electrochromic film based on polyaniline and TiO2 nanorods array

Titanium dioxide (TiO₂) nanorods (NRs) array was successfully prepared via hydrothermal method on fluorine doped tinoxide (FTO) coated transparent conductive glass substrate. The hybrid film of polyaniline (PANI)/TiO₂ NRs was achieved through electrochemical polymerization of aniline onto the TiO₂ NRs array film. The electrochromic and optical properties of the hybrid film were investigated by cyclic voltammetry (CV), amperometric i–t and UV–vis spectroscopy. The results indicate that the hybrid film has long term stability and reversible color changes after cyclic voltammetry scans for 200 circles. The PANI/TiO₂ NRs hybrid film can show three different colors. Response time of PANI/TiO₂ NRs hybrid film is about 0.7 s and 2.6 s at different states, respectively. The TiO₂ NRs array and the loose, porous surface among the hybrid film facilitate charge transmission and also provide large surface area for electrochemical reaction.     

一种新结构介观压光型微加速度计

对镜像异质三周期光子晶体的研究理论表明,在实际应用范围内,透射率与光子晶体所受的轴向应力呈简单的线性关系。据此,设计一种能实现微梁直拉直压的加速度计,微梁很小很敏感,处于轴向直拉直压位置时,能极大提高结构的灵敏度和自由振动频率。以镜像异质三光子晶体替代以往的压敏电阻,只需检测其透射率,即可得出加速度大小。最后结果表明:当透射光强改变1时,该结构可以感知小于0.4 mgn的加速度的变化,测量量程可达3.2 gn。     

一种新的基于Kerberos的认证授权协议

Kerberos协议是近年来广泛应用的身份认证协议之一,但是Kerberos协议的研究主要集中在身份认证部分,并未提供授权管理。这里在对Kerberos协议的基本原理及安全性进行分析的基础上,提出一种基于EAP和XACML授权框架的Kerberos认证授权模型,最后对此模型的认证授权能力进行分析。     

Switchable diffractive optics using patterned PEDOT:PSS based electrochromic thin-films

We demonstrate switchable, thin film diffractive optical gratings and Fresnel zone plate lenses fabricated using a micro-patterned electrochromic polymer and gel electrolyte. Electrochemically switching the conductive polymer PEDOT:PSS causes the patterned layer to change between a low-absorption to high absorption state, acting as an amplitude diffractive optical element. The switchable lens and gratings were fabricated using a lithographically patterned electrochromic polymer, a gel electrolyte, and an ITO-coated glass substrate. Within an applied voltage of −1 V to 1 V, the diffraction efficiency of the switchable lens can be varied 4.1-fold between the ‘on’ and ‘off’ states. Due to their low actuation voltage and biocompatibility, electrochemically actuated diffractive optics have potential applications in low power and implantable biomedical devices.     

基于CPLD的新型视频图像采集板

介绍一种在脱机态能够输出3种格式的视频图像采集板的设计方法，将CCD摄像头输出的视频信号解码成数字分量信号格式，然后在控制电路的控制下，输出标准的CIF、QCIF、SQCIF 3种图像格式之一，并存入帧存储器。计算机模拟和示波器测试表明该设计准确有效。该图像采集板可用于可视电话系统的前端采集部分，也可根据所需图像质量选择3种图像格式之一用于监控系统。     

一种新的序列图像匹配定位算法

景象匹配是飞行器导航定位中广泛采用的一项技术,如何提高图像的匹配概率,始终是该项技术中一个值得研究的课题。针对传统的利用单幅实时图像进行匹配时,存在的实时景象图过小、匹配特征不足,从而导致匹配效率过低的问题。文中研究了一种基于归一化灰度相关序列图像匹配算法,利用飞行器飞越匹配区时所得到的序列实时图像,在序列中各单幅图像匹配的基础上,利用一定的规则来综合单幅图像的匹配结果,从而得到最终匹配结果。实验证明,文中方法不仅能显著提高匹配性能,而且有较大的实用性。