含氟光敏单体液晶光控取向膜的光谱研究

制备了含氟光敏单体材料六氟戊二醇双肉桂酸酯,实验发现该材料在线性偏振紫外光辐照下可发生定向光交联反应.通过紫外可见光谱与红外光谱分析,表明光交联类型为[2 2]环加成反应.用原子力显微镜对单体光聚后形成的聚合物取向膜表面进行扫描,未观察到明显的各向异性分布现象.实验测得取向膜诱导液晶分子平行排列,取向效果均一,薄膜预倾角为1°～2°.     

聚合温度及铁电液晶有序度对单体转化率的影响

采用琉醇和丙烯酸的混合物作为反应单体,利用红外光谱仪检测反应前后单体的C=C双键吸收峰的变化,研究了温度对单体转化率的影响。制备了单体含量为10%的聚合物稳定铁电液晶器件,研究了铁电液晶有序度对单体的影响。实验表明:随着温度的增加单体的转化率增加,随着铁电液晶有序度的增加单体的转化率增加;在铁电液晶中单体的转化率主要受有序度的影响;制备聚合物稳定铁电液晶器件最佳的聚合条件为近晶A相(SmA)下聚合。     

低散射非偏振依赖的聚合物/液晶光栅

 了降低聚合物/液晶光栅的散射损失,并消除光栅的偏振依赖性,选取了低官能度的光敏单体作为反应体系,并逐步提高光栅的制备温度。首先选用五官能度的DPHPA （dipentaerythritol hydroxyl pentaacrylate）、双官能度的PDDA（ phthalic diglycol diacrylate）以及单官能度的NVP （N-vinylpyrrolidone）作为反应体系;其次,在制备过程中在光栅的后面放置加热台,逐步提升制备温度。实验结果表明：当制备温度上升到62 ℃以上,光栅有更多（36%）的液晶析出,相分离比常温下制备时要更完全一些,而且高温下制备的光栅其平整度更高,从而使光栅的散射损失比常温下减小了66.7%,器件的SEM图片也进一步证明了这个结论。同时高温制备也消除了液晶光栅的偏振依赖特性。     

光学相关论题 光化学

O644．1 2005053991 丙烯酸(4-N,N-二甲氨基肉桂酰氧乙基)酯及其水溶性聚 合物的合成及其光化学性质研究=Synthesis of(4-N,N- dimethylamine cinnamoylat ethyl)acrylate and its water soluble copolymers and their photochemical properties[刊, 中]／张锡兰(河南大学化学化工学院．河南,开封 (475001)),袁金芳…∥感光科学与光化学．-2005,23 (1)．-41-47 合成了一种新型感光性单体丙烯酸(4-N,N-二甲氨基 肉桂酰氧乙基)酯(DMACEA)及其与丙烯酸的共聚物P (DMACEA-co-AA)。用紫外吸收和荧光光谱研究了聚合 物溶液的光敏感性,用傅里叶红外光谱研究了聚合物成膜 后的光交联性及其过程。结果表明,DMACEA具有较好 的光敏性,P(DMACEA-co-AA)具有较好光交联性,交联 膜水溶胀和透光性也较好。图4参8(于晓光)     

用于液晶取向的掺偶氮类染料的光诱导取向膜

介绍了一种使用聚酰亚胺和偶氮类染料进行液晶光诱导取向技术,深入研究了代号为SY04包含两个偶氮基团的新偶氮类染料.通过对取向膜偏振吸收光谱的分析,讨论了这种混合材料光诱导取向机理.由于聚酰亚胺良好的成膜性使得这种光诱导取向膜具有很好的稳定性,偶氮类染料的引入使得液晶表面取向更加有序,从而获得了响应快速,电光特性优良的液晶盒.这种取向膜材料同时具有很好的热稳定性及抗紫外稳定性.     

聚芳醚非共轭性电致发光材料与器件

由单体Ma[2,5-二(2-乙基-己氧基)-1,4-双-{2,2-[5-(对-氟代苯基)]-1,3,4-噁二唑基}苯]分别与三组分单体(双酚A、砜代双酚A或混合的双酚A)在N,N-二甲基乙酰胺／甲苯／碳酸钾的催化下于165℃进行亲核取代聚合反应得到淡黄色的固体,进一步纯化后得到含噁二唑杂环的聚芳醚型非共轭的新型有机电致发光材料PE1、PE2、PE3。引入双侧链取代基增强了该类材料的溶解性能,通过控制反应条件及调节聚合温度获得了高收率的聚合产物。分别测得其化学物理性能,制备了聚合物PE1、PE2、PE3的简单结构器件(ITO／polymer／Ca／Ag),首次获得了该类材料单层器件的蓝色有机电致发光,且该类材料具有较优良的热稳定性。     

基于光控取向技术的液晶元器件研究

从液晶取向技术展开,介绍了液晶几何相位的基本原理和光控取向液晶元器件的制作工艺,通过实验制备了液晶透镜和液晶双焦点透镜样品,并在衍射光路中演示了其效果.相比于传统光学透镜,制备的液晶透镜和双焦点透镜的焦距和焦点位置可以按需预设在液晶样品中,其中双焦点透镜可实现焦距相等和焦距不相等的情况.此外,本实验制备的液晶样品还具备偏振控制的功能,通过调节入射光的偏振态可以切换目标光场的分布.     

聚合物网络稳定液晶膜的制备与研究

实验发现在液晶中添加少量的预聚物单体,利用光聚合诱导相分离的方法可以形成反型显示模式的聚合物网络稳定液晶膜。该膜在平时呈现透明态,在电场的调节下呈散射态。本文观察了在不同光照时间、不同光强下制得样品的聚合物网络织构,分析了在聚合过程中形成网络的形状、大小与致密程度,并对实验结果进行了相关的讨论。     

稀土有机光伏器件

采用真空气相沉积法制备了结构为ITO／TPD／Gd(DBM)3bath／Mg：Ag的双层结构有机光伏器件，其中，TPD为受体，Gd(DBM)3bath为给体。在4mW／cm^2的365nm波长紫外光从IT0玻璃方向垂直照射下，器件的开路电压Voc，短路电流Isc和填充因子FF分别为3．2V，29．24μA／cm^2，0．286。在实验中发现器件的外量子效率的光谱响应曲线与TPD的吸收光谱曲线基本一致，在紫外光照射下TPD／Gd(DBM)3bath膜层的界面处产生的激基复合物在光伏过程中扮演着至关重要的角色。     

基于液晶/聚合物光栅的高转化效率有机半导体激光器

采用有机半导体发光材料聚[2-甲氧基-5-(2-乙基己氧基)-1,4-苯乙炔]作为增益介质,低官能度光敏单体制备的液晶/聚合物光栅作为外部反馈谐振腔,制备出参数可独立控制的分离式结构的有机半导体激光器.液晶/聚合物光栅中液晶分子的取向影响光栅折射率调制量,从而影响光栅的反馈能力,最终影响激光器出射激光的性能.通过研究发现决定液晶分子取向的主要有两种与光栅周期有关的作用力,利用这一原理制备不同周期的光栅,光栅周期小于450 nm时,相分离出的液晶分子取向由光栅矢量方向变为光栅沟槽方向,此时光栅的折射率调制量增加,光反馈能力增强.采用周期为395 nm的液晶/聚合物光栅制备二级布拉格散射的有机半导体激光器,相较于大周期光栅(593 nm)制备的激光器,激光阈值由0.70μJ/pulse降低至0.18μJ/pulse,转化效率由2.5%提高到6.4%,且出射激光垂直于基板表面发射,有利于后续的处理及应用.     

Photoalignment of liquid crystals by cinnamate polyelectrolyte layer-by-layer ultrathin film

In this paper, a new layer-by-layer (LBL) ultrathin film with photosensitive cinnamoyl chromophores was prepared. It could induce uniform alignment of liquid crystals (LC) after irradiated by linearly polarized ultraviolet (LPUV) light. First, a photosensitive polycation containing cinnamoyl side groups was synthesized. Then a layer-by-layer ultrathin film was prepared in an aqueous solution of the polycations and poly (sodium 4-styrenesulphonate). The spectra of UV-vis absorption and ellipsometric measurement showed that the LBL film was uniform and suitable for the photoalignment of LC. When the film was irradiated by LPUV light, the cinnamoyl units in the film underwent [2 + 2] cycloaddition along the electric vector direction of the LPUV light. The polarized UV-vis spectra also proved that the film was anisotropic, and then the film could induce the homogeneous alignment of nematic LC. With the number of bilayers increasing, the alignment effect of multilayer film became better, and the contrast ratio became higher.     

Solid-phase photocatalytic degradation of polystyrene plastic with goethite modified by boron under UV-vis light irradiation

A novel photodegradable polyethylene-boron-goethite (PE-B-goethite) composite film was prepared by embedding the boron-doped goethite into the commercial polyethylene. The goethite catalyst was modified by boron in order to improve its photocatalytic efficiency under the ultraviolet and visible light irradiation. Solid-phase photocatalytic degradation of the PE-B-goethite composite film was carried out in an ambient air at room temperature under ultraviolet and visible light irradiation. The properties of composite films were compared with those of the pure PE films and the PE-goethite composite films through performing weight loss monitoring, scanning electron microscope (SEM) analysis, FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS). The photo-induced degradation of PE-B-goethite composite films was higher than that of the pure PE films and the PE-goethite composite films under the UV-irradiation, while there has been little change under the visible light irradiation. The weight loss of the PE-B-goethite (0.4 wt.%) composite film reached 12.6% under the UV-irradiation for 300 h. The photocatalytic degradation mechanism of the composite films was briefly discussed.     

Liquid-crystal alignment of phthalocyanine-derived Langmuir-Blodgett films

Twisted nematic liquid crystals were uniformly aligned on Phthalocyanine (Pc)-derived Langmuir-Blodgett (LB) films. By scanning tunneling microscopy imaging, it was found that the Pc-LB film has a well-ordered in-plane column-like structure oriented in the dipping direction, based on which the alignment mechanisms are discussed.     

非晶InGaZnO薄膜成分配比对透明性和迁移率的影响

利用固相反应法制备了富铟含量在不同成分配比下的高质量InGaZnO陶瓷靶材,采用脉冲激光沉积法,在基片温度为20℃、氧压为1Pa条件下,在石英玻璃衬底上生长了非晶InGaZnO薄膜,并对薄膜进行X射线衍射、透射吸收光谱、拉曼光谱与霍尔效应测试。通过对InGaZnO薄膜的测试表征,在较低温度条件下,铟含量较高的薄膜样品保持了非晶结构、可见光的高透明性和高电子迁移率,InGaZnO薄膜有望应用于电子器件。     

转光农膜的光谱特性研究

通过太阳光谱以及菊花、番茄作用光谱的测试分析 ,讨论了植物生长与太阳光谱的关系 ,表明太阳光谱中 2 80～ 380nm的紫外光 ,5 0 0～ 6 0 0nm的绿黄光及 72 0nm以上近红外光植物利用率较低 ,4 30～ 4 80nm的蓝紫光和 6 30～ 6 90nm的红光有利于增强光合作用。依据植物光合作用和太阳光谱特征 ,设计出CaS∶Cu ,Cl-蓝光膜 ,利用CaS∶Eu2 ,Mn2 ,Cl-,设计出绿光转红光的红光膜。讨论了红蓝复合双峰增益膜及紫外光转红光的稀土有机配合物的光谱特性。农用光能转换剂研制面临新的突破 ,利用反Stocks位移技术研制开发近红外光转红光膜值得关注     

Investigation of the surface of poly(ethylene terephthalate) films modified by vacuum ultraviolet irradiation in air

This paper reports on the results of measuring the changes in the characteristics of the surface of poly(ethylene terephthalate) films upon radiation-induced oxidation of the polymer under vacuum ultraviolet irradiation in an oxygen-containing medium. The films were irradiated by light from a sealed-off deuterium lamp with the maximum photon energy within the band (10 ±1 eV) in air under conditions where thermal destruction of poly(ethylene terephthalate) could be ignored. The functional relationship between the decrease in the film thickness and the growth of surface irregularities in the course of photoetching was established from measurements of the optical transmission spectra T (γ) of the films and investigations of the surface microrelief by atomic-force microscopy. The hydrophilic properties of the surface of the sample regions irradiated with different doses were examined by measuring the contact angle.     

脉冲激光沉积(PLD)法生长高质量ZnO薄膜及其发光性能

采用脉冲激光沉积(PLD)法在单晶Si(100)衬底上生长ZnO薄膜,以X射线衍射(XRD)、原子力显微镜(AFM)和透射电镜(TEM)等手段分析了所得ZnO薄膜的晶体结构和微观形貌。优化工艺(700℃,20Pa)下生长的ZnO薄膜呈c轴高度择优取向,柱状晶垂直衬底表面生长,结构致密均匀。室温光致发光(PL)谱分析结果表明,随着薄膜生长时O₂分压的增大,近带边紫外发光峰与深能级发光峰之比显著增强,表明薄膜的结晶性能和化学计量比都有了很大的改善。O₂分压为20Pa时所生长的ZnO薄膜具有较理想的化学计量比和较高的光学质量。     

Coherent transmittance of a polymer dispersed liquid crystal film in a strong field: Effect of correlation and polydispersity of droplets

A method for computing the coherent transmittance of a film of polymer dispersed nematic liquid crystals aligned by an external field in the case of an oblique incidence of light is developed, and a theoretical analysis of this quantity is performed. The effects of close packing are considered in terms of the interference approximation of the theory of multiple wave scattering. The correlation arising in the spatial distribution of polydisperse droplets is taken into account by introducing partial distribution functions. It is shown that an increase in the concentration of liquid crystal droplets is accompanied by an increase in the coherent transmittance of the film.     

高脉冲功率能量PLD法制备MgZnO薄膜中的沉积机理

用PLD法成功制备了一系列高质量的MgZnO薄膜。实验中发现高脉冲能量沉积薄膜的结构和发光特性随基片温度的变化规律与低脉冲能量下的结果不一样:基片在室温时高脉冲能量制备薄膜的XRD峰的半峰全宽比高基片温度时的结果相对更小;AFM显示其颗粒变大,柱状生长突出;PL谱紫峰与绿峰强度比最大,结晶质量反而提高。另一方面,与低脉冲能量时相反,增大氧气压强后高脉冲能量沉积的薄膜XRD半峰全宽变窄。结合实验现象和表征,合理解释了高脉冲能量沉积的机理。室温制备高质量MgZnO薄膜的PLD沉积机理对于以后在柔性衬底上沉积薄膜的研究有重要的参考价值。