ZnO纳米棒阵列在TiO2介孔薄膜上的生长及其表征

通过低温水热法成功地将ZnO纳米棒阵列定向生长在了介孔锐钛矿TiO2纳米晶薄膜上,并主要利用X射线衍射、场发射扫描电子显微镜和光致发光光谱等对其进行了表征。所制备的纳米棒具有六边形的端面,纳米棒的尺寸及端面边长分布范围窄,并且沿c轴方向(002)表现出了明显的择优化生长。此外,相比于玻璃基底或TiO2纳米颗粒薄膜,生长在介孔TiO2薄膜上的ZnO纳米棒阵列表现出了较好的取向生长,表明基底的表面结构和组成对ZnO纳米棒阵列的生长有显著的影响。根据基底有序的多孔结构,讨论了纳米棒阵列可能的生长机理。所得到的ZnO纳米棒阵列在室温下分别表现出了以370 nm为中心的强近紫外光和以530 nm为中心的弱绿光两条荧光谱带。     

纳米氧化锌的固相合成及其气敏特性

以酒石酸和乙二胺四乙酸为原料,分别与醋酸锌进行固相反应制得前驱化合物,进而热分解得到气敏材料氧化锌。用Ｘ射线粉末衍射和透射电镜对材料的陶瓷微结构进行了表征,并用静态配气法测试了材料在不同工作温度下对乙醇、氨气、液化石油气的灵敏度高,实验结果表明：用这种方法合成的氧化锌具有粒径小,工作温度低及对乙醇气体灵敏度高的特点。     

制备纳米氧化锌的新方法

以草酸和醋酸锌为原料，用室温固相化学反应首先制备前驱物二水合草酸锌，后者在微波场辐射分解得到产物纳米氧化锌。用XRD，TEM和IR等技术对产物的组成，大小及形貌进行了表征。结果表明：产物纳米氧化锌为粒度分布均匀的球形六角晶系结构，平均粒径约为8nm。     

氧化锌纳米点阵列体系的制备及发光性能

A novel nano-masking technique based on porous alumina membrane as mask was developed for preparing ZnO nanodots on Si substrate. The as-deposited nanodots with uniform size were in two-dimensional, regular array, whose regular structure and diameter were closely related to the mask used. Photoluminescence results show that the ZnO nanodot array have a strong UV light emission peak around 380 nm and a wide blue-green light emission peak at 460～610 nm at room temperature. The former corresponds to the near band edge emission of the wide band-gap ZnO and the latter could be attributed to the recombination of a photogenerated hole with singly ionized oxygen vacancy.     

铟掺杂氧化锌-氧化硅纳米电缆芯-壳异质结构的制备及表征

利用碳热还原反应气相沉积法制备了铟掺杂氧化锌-氧化硅纳米电缆芯-壳异质结构. X射线衍射(XRD)、透射电子显微镜(TEM)及X射线能谱(EDS)研究表明, 纳米电缆内芯为结晶完好的单晶纤锌矿结构, 外壳包覆一层氧化硅非晶层. 纳米电缆直径为30-60 nm, 长径比大于100. 掺杂纳米异质结构的生长机理与传统的金属晶种辅助气-液-固(VLS)机理有所不同. 这种掺杂纳米异质结构有望作为理想的结构单元应用于纳米器件领域.     

图案化锥形氧化锌纳米带的原位热氧化法制备与发光性质

采用光刻技术制备出图案的锌膜,所得锌膜与纯氧在700℃氧化反应10 min,在锌膜的表面上原位生长出具有图案的锥形ZnO纳米带阵列,实现了ZnO纳米带生长位置的可控生长。锌膜上得到的锥形ZnO纳米带为单晶六方纤锌矿结构,长度在1～4μm,纳米带根部和顶部的宽度分别在300～700 nm和100～300 nm。提出了锥形ZnO纳米带的可能生长机理。在波长为300nm光的激发下,发现了锌膜上锥形ZnO纳米带具有发光峰位于395 nm弱的紫外光发光和510 nm强的蓝绿光发光,它们分别起源于ZnO宽带隙的激子发射以及表面上离子化氧空位中的电子与价带中光激发的空穴之间的复合。     

醇热法制备ZnO纳米棒及其发光性能

在常压条件下,以油酸为分散剂一步反应醇热法制备ZnO纳米棒,利用XRD、SEM、TEM、HRTEM和FTIR等分析技术对产物进行了表征,对产物退火前后的光致发光性能进行了测试,并对ZnO纳米棒生长机理进行讨论. 结果表明,ZnO纳米棒沿[001]方向择优取向生长,直径为10～15 nm,长度为150～200 nm,油酸与ZnO表面Zn(Ⅱ)以螯合键形式相结合,具有良好的近紫外发光性能. 随着退火温度升高,产物深能级发光强度先降低后增加.     

表面改性的纳米氧化锌的制备及其吸收特性

自从８０年代Ｍａｊｉｅｖｉｅ的单分散超微粒合成技术取得成功以来［１,２］,制备单分散、不团聚的纳米材料一直是热门课题．纳米粒子的团聚会给制备、稳定化贮存及再复合时的均匀分散和高密度素胚的形成带来极大的困难［３］．本文报导了用超声微乳液法制备表面改性的单分散纳米氧化锌的条件,并对其光吸收特性研究时发现,不同的表面活性剂包覆会改变纳米材料的光吸收特性．１实验部分１．１纳米氧化锌的制备 将环己烷、醋酸丁酯及反应物水溶液分别用０．４５μｍ的超滤膜过滤,得到纯化试剂． １）将 ０． ２－０． ５ ｍＬ的 ０． ５…     

油分散性氧化锌纳米微粒的制备及表征

采用直接沉淀法制备了异丁酸修饰纳米氧化锌微粒，用XRD、TEM、XPS、IR、UV-Vis、PL等检测手段对样品进行结构表征。结果表明：所制的样品为纤锌矿结构的氧化锌颗粒，粒度约为20 nm，异丁酸分子与表面锌原子以双齿螯合的形式结合。 Zn(II)2p_3/2的结合能与Zn的标准峰位相比，向低结合能方向移动了1.5 eV，其在可见光区比紫外区的荧光发射显著增强。分散性实验表明，样品在有机溶剂中有良好的分散性。     

纳米ZnO的制备及发光特性研究

The samples of nano-size ZnO were prepared by precipitation, hydrolysis, sol-gel method and characterized by X-ray diffraction, Uv-Vis diffuse reflection spectrum, and time resolved luminescent spectrum. The results showed that the crystallite dimensions of all ZnO samples were coarsening with increasing annealing temperature and the grain sizes prepared by sol-gel method were obviously smaller than the others prepared by precipitation and hy-drolysis method. Under excitation of monochromatic light of wavelength 300nm, a strong and broad photolumines-cence (PL) emissions were observed in the wavelength range of 420～780nm. As the grain size decreased, the PL peak positions moved to shorter wavelengths. And as the annealing temperature increased, the peak intensity de-creased. The photoluminescence decay profile of ZnO was well described by three decay components of 46ns, 330ns and 1630ns.     

Characteristics of ZnO Particles Prepared by Au-catalyzed Phase Transport Technique

ZnO particles were prepared by Au-catalyzed vapor phase transport method on silicon substrate. Scanning electron microscopy(SEM) images show many ZnO particles were formed on the sample surface. They grew up layer by layer along the c-axis, which was confirmed by the results of X-ray diffraction(XRD). The morphology of ZnO particles is close to hemisphere and its formation process could be seen from the SEM image. The room temperature photoluminescence(PL) measurement revealed a narrow UV emission peak at 3.27 eV and a broad green emission peak at 2.45 eV, which was caused by the near-band-edge and deep-level emissions.     

Optical Properties of CdS Nanobelts and Nanosaws Synthesized by Thermal Evaporation Method

By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos-tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostructures. A combi-nation of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-tructures were observed and discussed.     

Luminescence Property and Synthesis of Sulfur-doped ZnO Nanowires by Electrochemical Deposition

"Sulfur-doped zinc oxide (ZnO) nanowires were successfully synthesized by an electric field-assisted electrochemical deposition in porous anodized aluminum oxide template at room temperature. The structure, morphology, chemical composition and photoluminescence properties of the as-synthesized ZnO:S nanostructures were investigated. X-ray diffraction and the selected area electron diffraction results reveal that the as-ynthesized products are single phase with hexagonal wurtzite structure with a highly preferential orientation in the (101) direction. Transmission electron microscopy observations indicate that the nanowires are niform with an average diameter of 70 nm and length up to several tens of micrometers. X-ray photoelectron pectroscopy further reveals the presence of S in the ZnO nanowires. Room-temperature photoluminescences observed in the sulfur-doped ZnO nanowires which exhibits strong near-band-edge ultraviolet peaks at 378 and 392 nm and weak green emissions at 533 and 507 nm. A blue emission at 456 nm and violet emissions at around 406, 420, and 434 nm were also observed in the PL spectrum for the as-synthesized ZnO:S nanowires. The PL spectrum shows that S-doping had an obvious effect on the luminescence property of typical ZnO nanowires."     

Preparation and Photoluminescence of ZnO Comb-Like Structure and Nanorod Arrays

A large quantity of Zinc oxide (ZnO) comb-like structure and high-density well-aligned ZnO nanorod arrays were prepared on silicon substrate via thermal evaporation process without any catalyst. The morphology, growth mechanism, and optical properties of the both structures were investigated using XRD, SEM, TEM and PL. The resulting comb-teeth, with a diameter about 20 nm, growing along the 0001 direction have a well-defined epitaxial relationship with the comb ribbon. The ZnO nanorod arrays have a diameter about 200 nm and length up to several micrometers growing approximately vertical to the Si substrate. A ZnO film was obtained before the nanorods growth. A growth model is proposed for interpreting the growth mechanism of comb-like zigzag-notch nanostructure. Room temperature photoluminescence measurements under excitation wavelength of 325 nm showed that the ZnO comb-like nanostructure has a weak UV emission at around 384 nm and a strong green emission around 491 nm, which correspond to a near band-edge transition and the singly ionized oxygen vacancy, respectively. In contrast, a strong and sharp UV peak and a weak green peak was obtained from the ZnO nanorod arrays.     

Controlled synthesis of ZnO from nanospheres to micro-rods and its gas sensing studies

1D ZnO rods are synthesized using less explored hydrazine method. Here we find, besides being combustible hydrazine can also be used as a structure-directing agent. The ratio of zinc nitrate (ZN) to hydrazine is found to control the morphology of ZnO. At lower concentration of ZN as compared with hydrazine the morphology of ZnO is found to be spherical. As we increase the hydrazine content the morphology changes from spherical (diameter  100 nm) to the elongated structures including shapes like Y, T as well dumbbell (diameter  40 nm and length  150 nm). Interestingly for more than 50% of hydrazine ZnO micro-rods are formed. Such rods are of diameter  120 nm having length of about 1 μm for ZN to hydrazine ratio of 1:9, isolated as well as bundle of rods are seen in scanning electron microscopy (SEM). The X-ray diffraction (XRD) reveals the phase formation with average particle size of 37 nm as calculated using Scherrer's formula. The high-resolution transmission electron microscopy (HRTEM) is also done to confirm the d-spacing in ZnO. Gas sensing study for these samples shows high efficiency and selectivity towards LPG at all operating temperatures. Photoluminescence (PL) study for these samples is performed at room temperature to find potential application as photoelectric material.     

ZnO/Ag微米球的合成与光催化性能

用微波辅助多元醇法对预先制备的ZnO微米球进行修饰,合成了载银氧化锌微米球（ZnO/Ag）. 利用X射线衍射仪、场发射扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪、紫外-可见双光束分光光度计和光致发光光谱仪等对样品的结构、形貌和光学性能进行了表征. 在紫外光照射下,通过亚甲基蓝的降解反应研究了样品的光催化活性. 结果表明,所制备的ZnO/Ag微米球是由面心立方的Ag纳米颗粒附着在纤锌矿结构的ZnO球表面形成;与ZnO相比,ZnO/Ag的紫外-可见光吸收光谱发生明显红移,在紫外和可见光范围均有较强的吸收;随着Ag含量的增加,ZnO/Ag荧光光谱强度先减弱后增强;与ZnO相比,ZnO/Ag的光催化活性明显提高,AgNO₃ 浓度为0.05 mol/L时制得的ZnO/Ag光催化活性最高.     

Synthesis, Structure, and Photoluminescence Property of a Novel One-dimensional Inorganic-organic Hybrid Gallophosphate JGP-2

A novel one-dimensional inorganic-organic hybrid gallophosphate compound, Ga(2,2′-bipy)(HPO4)· (H2PO4)(denoted JGP-2) was synthesized hydrothermally with 2,2′-bipyridine as a ligand and characterized by X-ray powder diffraction (XRD), elemental analysis, inductively coupled plasma(ICP), TGA analysis, solid-state 31P NMR, and luminescence spectra and structurally determined by single-crystal X-ray diffraction analysis. JGP-2 crystallized in the triclinic system, space group Pī(No.2), with a=0.7818(1) nm, b=0...     

三维分级结构ZnO的制备及光催化性能

以聚乙烯醇/醋酸锌复合纳米纤维为模板, 采用模板辅助共沉积技术制备了三维尖晶石型ZnO纳米线/纳米纤维分级结构, 并采用SEM, XRD对其形貌和晶型结构进行了表征. 在光催化降解乙醛性能实验中, 三维分级结构ZnO表现出比纳米粒子和纤维更好的光催化性能. 这主要归因于ZnO纳米线的次级结构和开放的三维网络结构更有利于乙醛分子和氧分子的扩散和传输, 从而提高了乙醛的光降解速率.     

Preparation, structure and ultraviolet photoluminescence of ZnO films by a novel chemical method

A novel and simple chemical method was developed for the deposition of ZnO films from aqueous solution, integrating the merits of successive ionic layer adsorption and reaction with the chemical bath deposition technology. By this new method, dense and continuous ZnO thin films with good crystallinity can be prepared in a very short time, e.g., in about 20 min. Results show that as-deposited ZnO films on glass and Si (1 0 0) exhibit hexagonal wurtzite crystalline structure and the preferential orientation along (0 0 2) plane. With a dense and continuous appearance, the film is composed of ZnO particles in even size of 200-300 nm. The strong and sharp emission at 391 nm and several weak emissions at the wavelength band of 440-500 nm indicate the high optical quality and the stoichiometrical nature of obtained film. Mechanism analysis shows that the reaction duration in hot water and the drying process are vital important factors affecting the deposition process and the crystallization behavior of the film prepared via the aqueous solution route.