后续的KOH腐蚀对ZnO纳米棒阵列及性能的影响

采用化学沉积和KOH腐蚀结合的方法,在FTO导电玻璃上制备了ZnO纳米棒阵列。用XRD、SEM、I-V曲线对ZnO纳米棒阵列的结构和性能进行了表征。结果表明：ZnO纳米棒为单晶,属于六方纤锌矿结构。后续的KOH腐蚀有利于ZnO纳米阵列形貌的改变及光电性能的提高,将ZnO纳米棒阵列作为光阳极制备染料敏化太阳能电池,被KO...     

溶液生长ZnO一维纳米阵列及其复合纳米结构的研究进展

对溶液生长ZnO一维纳米阵列的研究进展进行了评述,分析了晶种制备和溶液生长过程中各工艺因素对阵列微观形貌的影响,并介绍了在溶液中通过控制定点成核并利用有机基团调控ZnO晶体生长习性的合成路线用于构筑ZnO复合纳米结构的最新研究,指出了溶液生长ZnO一维纳米阵列和构筑复合结构中存在的问题及今后的研究方向.     

后续的KOH腐蚀对ZnO纳米棒阵列及性能的影响

采用化学沉积和KOH腐蚀结合的方法,在FTO导电玻璃上制备了ZnO纳米棒阵列。用XRD、SEM、I-V曲线对ZnO纳米棒阵列的结构和性能进行了表征。结果表明:ZnO纳米棒为单晶,属于六方纤锌矿结构。后续的KOH腐蚀有利于ZnO纳米阵列形貌的改变及光电性能的提高,将ZnO纳米棒阵列作为光阳极制备染料敏化太阳能电池,被KOH腐蚀后的ZnO纳米棒阵列的光电转换效率(η)、短路电流(Jsc)、开路电压(Voc)分别达到1.2%、0.006A/cm2、0.557V,与未被KOH腐蚀的ZnO纳米棒相比,光电转换效率提高了1.05%。     

一维纳米ZnO阵列的制备及其在染料敏化太阳能电池方面的应用研究进展

一维定向生长的纳米ZnO阵列具有较高的高温强度、硬度、优异的化学稳定性和物理化学特性,在气敏传感器、场发射、纳米结构染料敏化太阳能电池等方面有着广泛的应用.制备一维ZnO结构的方法多种多样,如水热法、化学气相沉积法、超声化学法等.综述并比较了一维纳米ZnO阵列的结构特点、生长机理、制备方法及其在染料敏化太阳能电池方面的应用进展和光电特性,分析了一维纳米ZnO阵列的光电传输机理及国内外研究现状、应用前景和发展趋势.     

ZnO/TiO_2复合纳米材料的制备及其在染料敏化太阳电池中的运用

本文在长有ZnO纳米粒子作为"种子层"的FTO基底上用水热合成法制备了取向高度一致的ZnO纳米线阵列,用TiCl4的异丙醇溶液在ZnO纳米线阵列的表面生长了纳米结构的TiO2。利用扫描电子显微镜、能量散射谱、X射线衍射分别表征纳米材料的形貌和结构,用Raman光谱研究了材料的晶格结构特性。染料敏化太阳电池的性能测试表明,与纯ZnO作为光阳极相比,ZnO/TiO2复合纳米材料作为光阳极的器件,开路电压和填充因子都得到了提高。     

化学溶液法外延组装ZnO分级纳米结构

采用气相法、液相法相结合的方法外延组装了一种形貌新颖的复杂ZnO分级纳米结构--"纳米毛刷".首先用热蒸发的方法制备了宽面为极性面的ZnO纳米带,然后采用化学溶液法,在强碱溶液中在ZnO纳米带的极性面上外延生长Zno纳米棒阵列,实现了ZnO分级纳米结构"由下而上"地外延组装.采用负离子配位多面体生长基元模型讨论了ZnO分级纳米结构的外延组装机理.这种ZnO分级结构的实现,可望作为ZnO纳米器件的原型材料构建新型光电器件.     

ZnO纳米线/棒阵列结构制备原理及方法概述

概述了ZnO纳米线/棒阵列结构的用途、制备原理和方法,重点介绍气相合成法和液相合成法中的几种典型制备ZnO阵列结构方法。展望了ZnO纳米线/棒阵列结构的发展方向及应用前景。     

ZnO纳米材料制备及其场发射性能的研究

采用水热法制备形貌和尺寸各异的纳米ZnO材料。用X射线衍射分析仪(XRD)和扫描电子显微镜(SEM)测试产物结构和表面形貌,分析影响纳米ZnO材料生长的因素,探讨纳米ZnO的生长机理。研究了各种形貌ZnO阵列的场致发射特性。实验结果表明,在各种ZnO纳米结构中,纳米管的场致发射性能最好,其最大电流密度可达到0.2mA/cm2,开启场强2.5V/μm,为寻求良好场发射性能的ZnO纳米材料提供了一个可行的途径。     

ZnO纳米阵列的可控合成及其场发射特性

采用水热法在PS模板上制备了不同的ZnO纳米阵列,通过控制反应时间得到不同长径比的ZnO纳米阵列,真空场发射测试表明,使用PS模板的ZnO纳米阵列的场发射性能得到改善,主要因为长纳米棒与短纳米管交叉两层的阵列结构导致屏蔽效应减弱。较长反应时间制备的ZnO纳米棒具有较大的长径比,场发射较好。多次重复场发射测试发现,本实验制备的ZnO纳米棒阵列的场发射稳定性不是很好,还需进一步改善。     

纳米ZnO阵列形貌对其光催化降解性能的影响

利用溶液法在不同形貌基片上制备了ZnO纳米棒阵列。通过聚苯乙烯球自组装阵列控制模板基片的形貌,制备出具有周期性结构的ZnO纳米花点阵;进而通过反应离子刻蚀聚苯乙烯球模板,实现了ZnO周期性点阵由纳米花向纳米环的结构转变。以亚甲基蓝水溶液为目标降解物,比较了不同ZnO纳米棒阵列的光降解能力,发现单位基片面积上ZnO纳米棒的有效受光面积是影响ZnO纳米棒阵列光降解能力的重要因素。     

碲铟汞晶体制备及其热稳定性研究

以高纯Hg、In、Te单质为原料,通过元素直接化合反应合成了碲铟汞(MIT)多晶料,并利用合成的高纯多晶料,在特殊设计的坩埚中,采用垂直Bridgman法通过自发成核方式成功地生长了尺寸为Φ15mm×175mm的MIT单晶体.利用X射线粉末衍射技术对MIT晶体结构及物相进行的分析表明,所获得的晶体是单相的MIT晶体,为缺陷闪锌矿结构,空间群为F43m.采用高分辨X射线衍射仪测量了所生长MIT晶体的摇摆曲线,结果表明所得晶体完整性较好,为高质量的单晶体.对所生长的MIT晶体进行了热分析,发现在MIT晶体中有Hg溢出现象.     

Studies on growth and characterization of an NLO crystal: L-alanine hydrogen chloride (LAHC)

A nonlinear optical (NLO) salt viz. L-alanine hydrogen chloride (LAHC) has been synthesized and solubility of the synthesized salt in de-ionized water was determined at different temperatures. Single crystals of L-alanine hydrogen chloride (LAHC) salt were grown by solution method with slow evaporation technique. The grown crystals were characterized by single crystal X-ray diffraction (XRD) and powder XRD analyses to study the crystal structure. The crystallinity of LAHC crystal was confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. FTIR study was used to confirm the presence of various functional groups in the grown crystals. UV–visible transmittance spectrum was recorded to study the optical transparency of LAHC crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz–Perry powder test. The density of LAHC crystal was determined by floatation method. The mechanical strength of the crystal was estimated by Vickers hardness test. The grown crystals were subjected to TG/DTA analyses. The dielectric behavior of the sample was also studied.     

阴离子交换合成氧化锌纳米晶体粉新方法及粉体光催化活性

采用一种新型的液相掺杂方法——非水相离子交换除氯法制备掺锑纳米氧化锌。该方法是在中性条件下,严格在控制含水量的低极性溶剂中进行的反应。氯离子的去除与水解是同时进行的,以保证掺杂的准确性及均匀性,提出的乙酸异戊酯共沸蒸馏法回收得到的纳米材料具有高分散性,TEM照片表明其保持了合成时的粒径和形貌。XRD图谱表明,未经煅烧的掺杂纳米氧化锌具有明显晶体衍射峰的晶体。掺杂后纳米氧化锌紫外可见吸收光谱发生了紫移,而紫外的吸收增强,表明锑原子已经掺杂到ZnO的晶格之中。这种半导体材料对甲基红（MR）的光催化降解作用表明,掺杂极大地提高了氧化锌纳米晶体的降解效率,90min内对甲基红（MR）的降解率可高达97％,与纯氧化锌相比,提高了70％以上。     

溶胶-凝胶法合成Y_3Al_5O_(12):Ce~(3 ),Tb~(3 )稀土荧光粉的研究

采用溶胶－凝胶法在低温下合成了 Ｙ３Ａｌ５Ｏ１２：０．０８Ｃｅ３＋; ０．１２Ｔｂ３＋稀土荧光粉．通过 Ｘ射线衍射（ＸＲＤ）分析及激发、发射光谱测试结果表明：合成的粉末为ＹＡＧ晶体结构,粉体 的最大激发峰为２７３ｎｍ,最大发射峰为５４５ｎｍ,色坐标为：ｘ＝０．３３１;ｙ＝０．５５８,在２７３ｎｍ的紫 外光激发下发出明亮的绿光．     

聚丙烯接枝马来酸酐改性纳米ZnO/聚丙烯复合材料的成核结晶行为及力学性能

采用熔融共混法制备了nano-ZnO/聚丙烯(PP)复合材料,研究了相容剂聚丙烯接枝马来酸酐(PP-gMAH)的加入对nano-ZnO/PP复合材料的成核结晶行为、晶体结构、结晶形态以及力学性能的影响。结果表明,低添加量(质量分数小于5%)的nano-ZnO对PP有较好的β晶成核效应,而当其质量分数大于5%时,nano-ZnO对PP结晶有明显的异相成核作用,使PP结晶温度大幅度提高,PP结晶在(040)晶面呈现生长择优性;PP-gMAH的加入增强了nano-ZnO粒子与PP基体之间的界面相互作用,改善了纳米粒子的分散性,促进了PP基体的异相成核,提高了nano-ZnO/PP复合材料的拉伸强度和冲击强度,但却抑制了nano-ZnO诱导PP生成β晶。nano-ZnO/PP复合材料体系中因界面相互作用改善所致的韧性提高明显强于nano-ZnO诱导PP形成β晶的增韧效应。     

Effect of Nano-Sized ZnO on the Physical Properties of (Cu0.5Tl0.25Pb0.25)Ba2Ca2Cu3O10?δ

High-temperature superconductor phase of (Cu_0.5Tl_0.25Pb_0.25)-1223 was synthesized by solid-state reaction technique and characterized using X-ray powder diffraction (XRD). XRD analysis revealed that the prepared sample was nearly monophase and exhibited tetragonal structure with space group P4/mmm. Nano-zinc-oxide, prepared by Co-precipitation method, was added to the sample. ZnO-concentrations y varied from 0.0 to 2.0 wt.% of the sample’s mass. The prepared samples were investigated through XRD, scanning electron microscope (SEM), energy dispersive X-ray (EDX), particle size analyzer (PSA), differential scanning calorimeter (DSC), electrical resistivity and transport critical current density measurement. X-ray data analysis showed that the nano-Zn addition does not affect the tetragonal structure of (Cu_0.5Tl_0.25Pb_0.25)-1223 phase, whereas the lattice parameters showed an insignificant variation. The results of the superconducting transition temperature, the transport critical current density and melting point of the prepared samples were found to depend on nano-ZnO concentrations.     

溶胶-凝胶法合成Y3Al5O12:Ce3+,Tb3+稀土荧光粉的研究

采用溶胶-凝胶法在低温下合成了Y3Al5O12:0.08Ce^3 ,0.12Tb^3 稀土荧光粉。通过X射线衍射（XRD）分析及激发、发射光谱测试结果表明：合成的粉末为YAG晶体结构,粉体的最大激发峰为273nm,最大发射峰为545nm,色坐标为：x=0.331,y=0.558,在273nm的紫外光激发下发出明亮的绿光。     

高纯ZnAl_2O_4纳米颗粒的制备及其微结构分析

将机械力化学与超声波化学相结合制备出高纯度、结晶性良好的尖晶石型ZnAl_2O_4纳米颗粒。分析了样品的表面形貌、晶体结构及微观结构。研究结果表明:当焙烧温度为600~900℃时,ZnO与γ-Al_2O_3固相反应制备出高纯度、结晶性良好的尖晶石型ZnAl_2O_4纳米颗粒。随着焙烧温度的升高,材料的致密度增大,结晶度提高,平均孔径依次增大,比表面积明显下降,孔隙率降低。     

Effect of processing on the particle size of tin oxide nano-powders

Nano sized tin oxide powders have been synthesized via two different chemical routes namely solid-state and sol–gel route for the fabrication of tin oxide gas/odors sensor. The synthesized powders have been characterized by simultaneous thermo gravimetric and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR) spectroscopy. The effect of synthesis routes have been investigated on particle size and morphology of tin oxide powders. Powder XRD patterns show that the synthesized powders have tetragonal (rutile) crystal structure. FESEM of formed thick films reveal that powder prepared by solid-state reaction route is less agglomerated as compared to the powder prepared by sol–gel route. XRD and FESEM indicate that there is the formation of tin oxide nanoparticles in the range of 15–50 nm. FTIR spectrums of synthesized powders show Sn-O or Sn-O-Sn stretching modes and its lattice modes at 615 and 494 cm^?1.     

Crystallite sizes and lattice parameters of nano-biomagnetite particles

Average crystallite sizes of microbially synthesized pure, metal-, and lanthanide-substituted magnetite (bio-magnetite) were determined for a variety of incubation times and temperatures, substitutional elements and amounts, bacterial species, and precursor types. The intriguing difference between nanoparticle bio-magnetite and chemically synthesized magnetite (chem-magnetite) was that powder X-ray diffraction (XRD) data showed that the bio-magnetite exhibited slightly smaller lattice parameters, however, Raman Spectroscopy exhibited no difference in Fe-O bonding. These results indicate that bio-magnetite likely exhibits a more compact crystal structure with less uncoordinated iron on the surface suppressing negative pressure effects. The bio-magnetite with decreased lattice parameters could have potential technological advantages over current commercial chemically synthesized magnetites.