一步水热法制备超长VO_2(B)纳米带及其电化学性能（英文）

采用简易的一步水热法制备了超长的VO2(B)纳米带。对纳米带的结构、形貌、最优合成条件及电化学性能进行了研究。结果发现:制得的VO2(B)纳米带长度约为几十微米,宽度为~200 nm;且最优合成条件为在钒源与还原剂摩尔比为2:1的条件下,200℃水热反应24 h。当该VO2(B)纳米带被作为锂离子电池的阳极材料时,显示出了优异的电化学性能,尤其是循环稳定性,循环500周后的电容量损失率仅为10.41%,极大的解决了钒类纳米材料作为锂离子电池阳极材料时稳定性差的问题,提高了其成为锂离子电池阳极材料的可能性。     

NaCl熔盐法制备ZnO片状纳米晶及其光学性能研究

通过在NaCl熔剂的液态环境中热分解商业2ZnCO3·3Zn(OH)2固体粉末,成功制备出ZnO片状纳米晶。用X射线粉末衍射和透射显微镜研究了所制备纳米晶的成分、晶相、形状和尺寸。采用室温光致发光技术研究了ZnO片状纳米晶的发光性能。研究表明:所制备的ZnO片状纳米晶在波长为486nm处发出强蓝光。通过透射电子显微镜技术对ZnO纳米晶形态的深入研究,深入分析了ZnO片状纳米晶的生长过程,提出了在NaCl液态环境中,ZnO片状纳米晶按奥斯瓦尔德熟化机制生长。     

二氧化钛纳米线的制备及其光学性能研究

利用水热合成法,制备出了高比表面积锐钛矿型TiO2纳米线,并用XRD,SEM,PL,UV-Vis等手段对纳米线的物相、微观形貌、结构和性能进行表征。结果表明:产物为锐钛矿型TiO2纳米线,纳米线直径约为几十纳米,长度可达几微米以上;其紫外吸收光谱和光致发光谱相对于原料粉均呈现出蓝移现象;另外,还对TiO2纳米管的光催化性能也进行了初步探讨,研究表明TiO2纳米线具有较高比表面积,对提高其催化性能、吸收性能等方面具有积极的作用。     

还原五氧化二钒制备二氧化钒粉末

本文采用碳热法还原V2O5制备钒的低价氧化物VO2.用XRD分析生成物的相结构,用DSC/TGA的分析结果推测反应历程.结果表明:反应经历了674°C-710°C期间生成V6O13和710°C以上完全形成VO2的过程.将VO2与LAS玻璃复合烧结成陶瓷,对其进行阻温测试,结果表明:在室温至100°C间复合陶瓷电阻急骤下降,这是由VO2的半导体-金属相变效应引起的.     

二氧化钒的制备及应用研究

文章介绍了VO2的晶体结构及在智能温控材料方面的应用,综述了掺杂对VO2相变温度的调控和作为光学减反膜对可见光透过率的调控,分析了掺杂离子的性质、种类对VO2相变温度的影响,并对VO2的制备方法及其超细粉体的研究进展进行了总结。     

纳米ZnO溶胶的制备及其光学性能

以氯化锌和氢氧化钠为原料,采用多元醇法制备纳米ZnO溶胶。利用透射电镜、荧光光谱和紫外光谱对其进行表征,详细研究了水浴时间和pH值对纳米氧化锌形貌和光学性能的影响。结果表明:随着水浴处理时间的增长,纳米ZnO粒径有所增大,其紫外吸收光谱红移,紫外荧光增强,而黄-绿光荧光强度减弱。随着pH值的增大,纳米ZnO粒子的粒径逐渐减小,紫外吸收光谱蓝移,其紫外荧光逐渐增强。     

纳米-MnO2的制备及其性能研究

用溶胶－凝胶法制备纳米级α－ＭｎＯ２,并对实验条件进行了讨论．对所得的样品进行了ＸＲＤ、ＩＣＰ、ＴＥＭ、化学分析、恒流放电、循环伏安等一系列测试,并与国际一号样（Ｉ．Ｃ．ＮＯ．１电解二氧化锰）相比较．虽然纳米级α－ＭｎＯ２的单独放电性能并不好,但是当纳米级α－ＭｎＯ２以一定比例与Ｉ．Ｃ．Ｎｏ．１号样混合时,在浅度和深度放电区内的放电容量都比Ｉ．Ｃ．Ｎｏ．１高．     

磁控溅射制备纳米二氧化钒半导体薄膜及表征

本文采用射频磁控溅射法,结合氩气气氛退火工艺制备了VO2薄膜。通过优化磁控溅射和热退火工艺,结合激光拉曼光谱仪(Raman)、X射线光电子能谱(XPS)、电镜扫描(SEM)对薄膜的相结构、组分和表面形貌进行分析。结果表明:溅射衬底温度为150℃,在450℃氩气气氛退火2.5 h能制备出高质量的VO2薄膜,表面呈米粒状,有一定的取向性。     

热致变色VO2薄膜的制备及光学性能研究

利用等离子体发射光谱监测系统(PEM)控制钒的等离子强度,在石英基底上磁控溅射制备了VO2薄膜。采用XRD、XPS、SEM、紫外-可见-近红外分光光度计及傅立叶红外分光光度计研究薄膜的结构、光学及相变特性。结果表明,所制备的VO2薄膜具有(011)取向,VO2薄膜的热滞回线宽度为25℃,可见光透过率和太阳光调节率分别可达Tlum,l=34.1%、Tlum,h=35.3%和ΔTsol=6.8%,相变前后,红外光区的反射率变化最大值可达44.4%。     

氧化锌/环氧纳米复合材料的制备及其光学性能研究

采用均相沉淀法制备了氧化锌(ZnO)前驱体,通过煅烧前驱体制备了不同粒径的ZnO纳米颗粒,并在此基础上制备了ZnO/环氧纳米复合材料.借助TG、XRD和TEM等手段对纳米ZnO进行了表征,采用UV-VIS研究了ZnO含量、颗粒粒径等因素对复合材料光学性能的影响.研究结果表明:在紫外光区,提高ZnO的含量和选择ZnO最佳粒径,可以改善对紫外光的屏蔽效果;随着ZnO粒径的减小,ZnO对紫外光的屏蔽存在明显的蓝移现象,因此选择合适的粒径尤为重要.在可见光区,ZnO含量和颗粒粒径的影响相似,当ZnO含量低于0.07wt%、粒径小于27nm时复合材料的透过率几乎没有变化,增加含量或增大粒径透过率则随之下降.当ZnO的粒径为27nm时,添加0.07wt%的ZnO所制备的ZnO/环氧纳米复合材料具有优异的光学性能:在保持可见光区高透明性的同时又能够对紫外光区有良好的屏蔽效果,能够满足LED封装等光学器件的需要.     

Preparation and optical properties of phase-change VO2 thin films

In this work, VO₂ thin films were prepared on three kinds of substrates by the sol-gel dipcoating method followed by heat treatment under vacuum. These thin films were analysed by x-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The infrared and ultraviolet-visible spectra of the VO₂ thin films were also recorded during heating and cooling between room temperature and 100°C. The experimental results show that VO₂ thin films thus prepared exhibit thermally induced reversible phase transition, and the largest changes in transmittance and reflectivity are approximately 58 and 25%, respectively, in the case of vacuum heat treatment at 400°C and silica glass substrates. The refractive index (n) decreases and the absorption coefficient (k) increases when heating these thin films from room temperature to 100°C, and vice versa for cooling. The reasons why the optical constants and infrared absorption spectra change so remarkably are discussed.     

无机溶胶-凝胶法制备B型和M型VO2粉体

以V2P5为原料,采用无机溶胶-凝胶法制备出V2O5粉体,在H2气氛下热处理得到了VO2(B)粉体,再在Ar气氛下热处理VO2(B)粉体,制备出了VO2(M)粉体.采用X射线衍射(XRD)、红外吸收光谱(IR)、差热分析(DTA)等方法对样品进行了成分和结构分析,结果表明,当热处理温度为500℃、H2浓度50%时,得到VO2(B)粉体;然后,在Ar气氛下分别经过550、600、650、700℃处理1h后,VO2由B型向M型转变,700℃处理成功制备出了VO2(M)粉体.     

VO2薄膜的制备及其热致相变特性研究

以双氧水和V2O5粉末为前驱体制备出V2O5溶胶,然后在云母基底上成膜,通过后续热处理退火得到优异相变性能的VO2薄膜。采用SEM、XRD分析薄膜形貌和微观结构,利用FT-IR等检测薄膜的光学性质。实验表明,VO2薄膜在云母基底上沿(011)晶面择优取向生长,颗粒生长致密且大小分布均匀。薄膜具有优异的相变陡然性,相变温度及滞后温宽都较低。在红外波段,相变前后透过率及反射率变化都较大,对红外光调节性能较好;在可见光波段,薄膜在相变前后都具有较高可见光透过率。     

Preparation of VO2 thin film and its direct optical bit recording characteristics

Vanadium dioxide (VO2) film which has nearly the same transition point as single crystal has been obtained by reactive evaporation of vanadium on glass and subsequent annealing in N2 gas. Relations between optical properties of V02 film and its preparation conditions are presented. We made optical direct bit recording on V02 film using a laser diode as the light source. The threshold recording energy and bit density are 2 mJ/cm 2 and 350 bits/mm, respectively. We also made tungsten doping to lower the V02 film transition temperature.     

Facile synthesis,phase transition,optical switching and oxidation resistance properties of belt-like VO2(A) and VO2(M) with a rectangular cross section

Belt-like VO₂(A) with a rectangular cross section (VA-RCS) was successfully synthesized using V₂O₅, H₂C₂O₄·2H₂O and H₂O as the starting materials by a facile hydrothermal approach. Some synthetic parameters, such as, the reaction time, reaction temperature and concentration of H₂C₂O₄·2H₂O, were systematically investigated to control the fabrication of belt-like VA-RCS. The formation mechanism of belt-like VA-RCS was proposed. Subsequently, belt-like VO₂(M) with a rectangular cross section (VM-RCS) was prepared by the irreversible transformation of VA-RCS at 700 °C for 2 h under the inert atmosphere. The phase transition temperature (T_c) of VA-RCS and VM-RCS was evaluated by DSC test. The optical switching properties of VA-RCS and VM-RCS were studied by the variable-temperature infrared spectra, and it was found that the as-obtained VA-RCS and VM-RCS could be used as the optical switching materials. Furthermore, the oxidation resistance properties of VA-RCS and VM-RCS were investigated by TGA, indicating that they have good thermal stability and oxidation resistance below 400 °C in air.     

Hydrothermal synthesis of single-crystal VO2(B) nanobelts

Single crystalline VO₂(B) nanobelts with a metastable structure were obtained through a simple hydrothermal synthetic method. The VO₂(B) nanobelts were characterized by means of X-ray diffraction, transmission electron microscopy, selected area electronic diffraction, field-emission scanning electron microscopy and X-ray energy-dispersive spectroscopy techniques. The as-obtained VO₂(B) nanobelts are 400–600 nm long, typically 100–150 nm wide and 20–30 nm thick. The belt-like VO₂(B) with a high surface area may be beneficial to lithium insertion between the VO₆ layers for application in batteries.     

Nanoporous thermochromic VO(2) films with low optical constants, enhanced luminous transmittance and thermochromic properties

Nanoporous thermochromic VO(2) films with low optical constants and tunable thicknesses have been prepared by polymer-assisted deposition. The film porosity and thickness change the interference relationship of light reflected from the film-substrate and the air-film interfaces, strongly influencing the optical properties of these VO(2) films. Our optimized single-layered VO(2) films exhibit high integrated luminous transmittance (T(lum,l) = 43.3%, T(lum,h) = 39.9%) and solar modulation (ΔT(sol) = 14.1%, from T(sol,l) = 42.9% to T(sol,h) = 28.8%), which are comparable to those of five-layered TiO(2)/VO(2)/TiO(2)/VO(2)/TiO(2) films (T(lum,l) = 45%, T(lum,h) = 42% and ΔT(sol) = 12%, from T(sol,l) = 52% to T(sol,h) = 40%, from Phys. Status Solidi A2009, 206, 2155-2160.). Optical calculations suggest that the performance could be further improved by increasing the porosity.     

聚芴/乙基氰乙基纤维素共混物超薄膜的形态和光学性能

通过旋涂成膜方法制备了聚芴(PF)/乙基氰乙基纤维素[(E-CE)C]共混物超薄膜(厚度约为50nm),用原子力显微镜(AFM)、透射电子显微镜(TEM)研究了共混物超薄膜形态结构,并用荧光光谱仪研究了共混物超薄膜中聚芴的光致发光性能.实验发现,超薄膜表面形态结构分布均一,相结构随着(E-CE)C含量增加有规律的变化,表现为PF逐渐被(E-CE)C均匀"分隔"开来.还发现该超薄膜在纳米尺度范围内发生垂面微相分离.同时,超薄膜中聚芴发射光谱随(E-CE)C含量增加发生蓝移,发射峰半高宽变窄.实验结果表明高速旋涂制得的超薄膜形态结构表现出显著的浓度依赖性,明显地影响PF发射光谱性质.     

Hydrothermal synthesis of W and Mo co-doped VO2(B) nanobelts

W and Mo co-doped VO₂(B) nanobelts which used formic acid as reduction acid, NH₄VO₃ as vanadium source, (NH₄)₆W₇O₂₄?·?6H₂O and (NH₄)₆Mo₇O₂₄?·?4H₂O as doped sources were synthesised by the hydrothermal method. The samples were characterised by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). TEM and HRTEM images showed the samples had a length of 1?µm and a width of 100?nm. XRD, FTIR and XPS spectra revealed that Mo⁶⁺ and W⁶⁺ incorporated into the VO₂(B) lattice and formed solid-solution phases with VO₂(B).