ZnO/ZnS纳米颗粒的制备和光谱特性研究

用胶体化学法制备了ZnO/ZnS纳米颗粒 ,并且用超声分散的方法对其进行表面修饰 ,表面修饰的效果很好。ZnO和ZnO/ZnS纳米颗粒的光学带隙分别为 3.88eV和 4 .6 0eV ,ZnO纳米颗粒的荧光峰为 4 2 2nm ,而ZnO/ZnS纳米颗粒的荧光主峰在 2 99nm ,而且有对称的肩峰 2 6 8nm和 332nm ;表面修饰后的ZnO和ZnO/ZnS纳米颗粒的光学带隙分别为 3.10eV和 2 .93eV ,而ZnO/ZnS纳米颗粒的荧光峰在 311nm处表现出“红移”现象     

硫掺杂煤基石墨烯量子点制备及其对Ag~+的检测

以太西无烟煤为原料,采用超声液相剥离法制备得到煤基石墨烯量子点(Coal based graphene quantum dots, C-GQDs),以3-巯基丙酸为硫源采用水热合成法成功制备了硫掺杂煤基石墨烯量子点(Sulfur doped coal-based graphene quantum dots, SC-GQDs),探讨了不同比例的硫源掺杂对产物荧光量子产率的影响。采用透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)、紫外可见吸收光谱(UV-vis)及荧光光谱(PL)对所制备的S-C-GQDs形貌结构及其光学性质进行表征和测定。结果表明:S-CGQDs大小均一,分布均匀,粒径分布12～16 nm;当C-GQDs和硫源的质量比例为1︰30时,S-C-GQDs的量子产率可达46%。硫掺杂极大改变了产物的电子活性和化学性质,使S-C-GQDs对Ag+检测具有较高的选择性。     

声化学-微波水热法合成α-ZnS纳米晶及其光学性能

采用声化学法制备了ZnS纳米前驱体,经过一定时间的微波水热后处理得到ZnS纳米晶.利用X-射线粉末衍射(XRD)、透射电子显微镜(TEM),选区电子衍射分析(SAED),紫外可见光谱(UV-Vis),红外光谱(IR)以及光致发光光谱(PL)等手段对样品进行了测试表征.结果表明,所制备的ZnS纳米粒子粒径约为5～10 nm,为α-ZnS纤锌矿结构,六方晶系,禁带宽度Eg为3.91 eV.经微波水热处理30 min所制备的试样具有最佳的光致发光性能.     

Zn~(2+)、OH~-物质的量比对ZnO形貌和光催化活性的影响

以乙酸锌[Zn(CH_3COOH)_2·2H_2O]为锌源、乙二醇(EG)作为辅助剂,通过与不同量的NaOH反应得到前躯体,再将前躯体在水热条件下转化为ZnO;采用XRD、SEM、TEM等对前躯体和ZnO产物的晶相和形貌进行了表征。结果表明,水热合成产物都是具有六方纤锌矿结构的ZnO,但随着NaOH加入量的增加,在原料溶液中Zn~(2+)和OH~-的物质的量比分别为1∶1、1∶3、1∶6时,ZnO产物分别呈棒状、颗粒状和片状。测试了ZnO在波长为365 nm光照下降解甲基橙溶液能力,活性次序为:片状ZnO颗粒状ZnO棒状ZnO,表明ZnO形貌及其晶面对其光催化活性具有明显影响。     

稀土掺杂ZnO纳米材料的制备与表征

采用超声化学法，以六水合硝酸锌、六水合硝酸铕和三乙醇胺为原料，在加入聚乙二醇20000的水中进行反应，制备了呈球状的纳米ZnO:Dy³⁺。采用微波水热法制备ZnO:Eu³⁺纳米材料。采用X射线衍射(XRD)、场致发射扫描电镜(SEM)、紫外-可见光谱(UV-Vis)、光致发光谱(PL)等技术对所制备的样品进行了系列表征。结果表明：掺杂后并未改变纳米颗粒的晶型结构，紫外-可见吸收光谱显示其在紫外、可见光区域的吸收能力均有所增强；荧光光谱显示在紫外、可见光区存在多个发光峰，掺杂后发光强度增强。     

ZnS/PAA纳米复合材料的制备及发光性能研究

以氯化锌、硫化钠及丙烯酸(AA)为原料,偶氮二异丁氰(AIBN)为引发剂,采用原位一步法合成制备ZnS/PAA纳米复合材料。利用X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、红外光谱仪(IR)、紫外-可见光谱仪(UV-Vis)、荧光光谱(PL)研究了ZnS/PAA的结构、形貌组成,并研究了反应时间、反应温度及有机单体用量对目标产物发光性能的影响。结果表明,反应温度、反应时间以及单体的量都对ZnS/PAA纳米复合材料的发光性能有影响。合成ZnS/PAA的最佳试验条件:单体AA的体积用量4mL,反应温度50℃,反应时间4h,此时ZnS/PAA纳米复合材料有最优的发光性能。     

ZnO纳米墙薄膜的低温水热制备及其性能研究

利用控制水解浸涂法在氧化铟锡(ITO)导电玻璃上制备籽晶层,进而通过低温水热法和热处理获得了独特的氧化锌(ZnO)纳米墙薄膜结构。通过X射线衍射谱(XRD)、扫描电镜(SEM)、光电子能谱(EDS)、红外光谱(FTIR)、紫外-可见光谱(UV-Vis)和光致发光谱(PL)等对薄膜的形貌、组成和结构进行了分析表征。研究表明,ZnO纳米墙由20～100 nm厚的片层交织而成,在热处理前薄膜的组成为混合的ZnO、醋酸锌(ZnAc)和羟基醋酸锌(Zn-LHS),经500°C热处理脱除CO2、H2O等小分子后基本完全转变为ZnO,而原有层状交织纳米墙结构保留下来。室温PL谱显示薄膜在383 nm处有较强烈的紫外激发峰。结合晶体生长理论探讨了ZnO纳米墙薄膜的生长机制。     

ZnO一维纳米材料的热蒸发法制备及光学性能研究

以Zn粉为原料,在1050℃空气气氛中采用热蒸发法成功制备了ZnO一维纳米材料.探讨了覆盖瓷舟对ZnO纳米晶的形成及其形貌和光学性能的影响.X射线衍射(XRD)分析表明,产物是纯六方纤锌矿结构的ZnO;扫描电子显微镜(SEM)形貌观察显示,产物为ZnO纳米线、微纳米棒和四角针状ZnO;光致发光谱(PL)表明ZnO一维纳米材料主要有3个蓝光发光带;紫外-可见光光谱(UV-vis)显示ZnO一维纳米材料能有效的催化降解次甲基蓝溶液.     

Al掺杂对甲醇醇解法合成ZnO纳米粉体的影响

采用醇解法,在130℃的甲醇溶液中分别合成纯的和Al掺杂纳米氧化锌(ZnO)晶体.使用X射线衍射仪,透射电子显微镜,Fourier红外光谱和偏振稳态荧光光谱对其晶体结构和光学性能进行了表征.结果表明:在甲醇溶液中,在较低的温度(130℃)下,成功制备出纳米ZnO晶体.Fourier红外吸收光谱表明醇解法合成的ZnO纳米晶体含有较少的有机物杂质.荧光光谱结果可以看出,纯ZnO和Al掺杂的ZnO纳米晶体在可见光范围(400nm～700nm)内有一个高的蓝光发光带(峰位为440nm)和一个绿光发光带(纯的和Al掺杂的峰位分别为520nm和530nm).通过对比发现掺杂Al可以有效的改变ZnO纳米粉体的可见光发光特性.     

Eu~(3+)掺杂ZnO纳米材料的制备与表征

采用超声化学法,以六水合硝酸锌、六水合硝酸铕和三乙醇胺为原料,在加入聚乙二醇20000的水中进行反应,制备了呈球状的纳米ZnO:Eu~(3+)。采用X射线衍射(XRD)、场致发射扫描电镜(SEM)、紫外-可见光谱(UVVis)、光致发光谱(PL)等技术对所制备的样品进行了系列表征。结果表明,掺杂后并未改变纳米颗粒的晶型结构,紫外-可见吸收光谱显示其在紫外、可见光区域的吸收能力均有所增强;荧光光谱显示在紫外、可见光区存在多个发光峰,掺杂后发光强度增强。     

Synthesis and Luminescence Properties of Core/Shell ZnS:Mn/ZnO Nanoparticles

In this paper the influence of ZnO shell thickness on the luminescence properties of Mn-doped ZnS nanoparticles is studied. Transmission electron microscopy (TEM) images showed that the average diameter of ZnS:Mn nanoparticles is around 14 nm. The formation of ZnO shells on the surface of ZnS:Mn nanoparticles was confirmed by X-ray diffraction (XRD) patterns, high-resolution TEM (HRTEM) images, and X-ray photoelectron spectroscopy (XPS) measurements. A strong increase followed by a gradual decline was observed in the room temperature photoluminescence (PL) spectra with the thickening of the ZnO shell. The photoluminescence excitation (PLE) spectra exhibited a blue shift in ZnO-coated ZnS:Mn nanoparticles compared with the uncoated ones. It is shown that the PL enhancement and the blue shift of optimum excitation wavelength are led by the ZnO-induced surface passivation and compressive stress on the ZnS:Mn cores.     

Sonochemistry synthesis and enhanced photocatalytic H2-production activity of nanocrystals embedded in CdS/ZnS/In2S3 microspheres

ZnS and CdS nanocrystals with a size of 5-10 nm embedded in CdS/ZnS/In(2)S(3) microspheres have been successfully synthesized by a sonochemistry method at room temperature and normal pressure without the use of templates or surfactants. The as-prepared products have been characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), EDX line spectrum, high-angle annular dark-field imaging (HAADF), UV-visible diffuse reflectance spectra (UV-vis) and photoluminescence (PL) spectra. The reaction process in the solution under ultrasonic irradiation was investigated by gas chromatography-mass spectrometry (GC-MS). The mechanisms of phase formation and morphology control of CdS/ZnS/In(2)S(3) microspheres are proposed and discussed in detail. Furthermore, the photocatalytic activity of CdS/ZnS/In(2)S(3) for water splitting was investigated under visible-light irradiation (λ > 400 nm) and an especially high photocatalytic activity (apparent yield is 40.9% at 420 nm) was achieved in the absence of co-catalysts.     

微乳液中纳米ZnS、CdS微粒的合成与表征

以乙酸锌、硝酸镉和硫化钠为原料,室温下,采用微乳液法合成ZnS、CdS纳米粒子。利用rIEM、XRD、Raman、UV-Vis和PL等检测手段对产物进行表征。结果表明,合成的zns纳米晶粒径在25m左右,为立方β-Zns晶相;ω值对合成纳米cds的形貌和粒径产生重要影响,纳米Cds粒径为5nm左右,在紫外吸收光谱和荧光发射光谱上均表现出明显的特征,可作为荧光量子点使用。     

Dispersion of Surface Modified Nanostructure Zinc Oxide in Optically Active Poly(Amide-Imide) Containing Pyromellitoyl-bis-L-isoleucine Segments: Nanocomposite Preparation and Morphological Investigation

Optically active zinc oxide/poly(amide-imide) (PAI) nanocomposites (NC)s were synthesized by using ultrasonic assisted technique. The polymers and zinc oxide (ZnO) nanoparticles were physically and/or chemically connected with each other through different kinds of interactions such as physical van der Waals forces, hydrogen bonding and/or covalent interactions. ZnO/PAI NCs were characterized by Fourier transform infrared spectra, X-ray diffraction patterns, and field emission scanning electron microscopy. The thermal stability studies indicated an enhancement of thermal stability of new NC materials compared with the pure polymer.     

Growth and characterization of the Al-doped and Al–Sn co-doped ZnO nanostructures

In the present work, well-dispersed structures of spherical-like pure ZnO, Al doped ZnO (AZO) and Al, Sn co-doped ZnO (ATZO) nanocrystals were successfully synthesized by using zinc acetate dihydrate as the starting material and also the low temperature hydrothermal process without any additional surfactant or catalytic agent. The ZnO structures were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The XRD results revealed that ZnO powders have a hexagonal crystal structure and the TEM indicated that the nanoparticles self-aggregate. An X-ray photoelectron spectroscopy (XPS) study confirmed the substitution of Zn²⁺ by Sn and Al ions. Optical properties of the ZnO structures were investigated by Raman spectroscopy and room-temperature photoluminescence (PL) spectroscopy. The Raman spectroscopy results demonstrated that the doped ZnO nanoparticles had a higher crystalline quality than that of pure ZnO. Room-temperature PL spectra of these structures showed a strong UV emission peak and a relative weak green emission peak, and the UV peak of the doped ZnO nanoparticles was blue-shifted with respect to that of the undoped ZnO nanoparticles.     

Low‐temperature synthesis of nano‐to‐submicron size organo‐zinc oxide and its effect on properties of polybutadiene rubber

Nano‐to‐submicron sized particles of zinc oxide (ZnO) were synthesized by low temperature hydrolysis method. Organo‐ZnO was also synthesized by the aforementioned method in presence of polyethylene glycol (PEG‐2000). The synthesized ZnO particles were characterized by infra‐red spectroscopy, X‐ray diffraction, BET surface area, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). FTIR showed that PEG was present on the ZnO surface. Organo‐ZnO exhibited floral‐shape morphology consisting of concentric nanorods. The average diameter of the nanorods was ～ 250 nm as evident from SEM. TEM showed that the nanorods were made of ～ 50 nm sized small particles. UV‐absorbance property of ZnO was unaltered even after organic coating. Curing, physico‐mechanical and thermal properties of polybutadiene rubber compounded with organo‐ZnO were compared with those of standard commercial rubber grade ZnO and nano‐ZnO prepared by high and low temperature methods. The cure‐characteristics were studied with the help of moving die rheometer as well as differential scanning calorimetry (DSC). Crosslink‐density measurement along the DSC vulcanization exotherm showed better cure efficiency of organo‐ZnO. Organo‐ZnO containing compound exhibited better mechanical and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of silane-modified ZnO on morphology and properties of bionanocomposites based on poly(ester-amide) containing tyrosine linkages

In this study, various optically active poly(ester-amide)/Zinc oxide bionanocomposites (PEA/ZnO BNCs) were synthesized with different amount of modified ZnO nanoparticles using ultrasonic irradiation. To obtain the homogeneous distribution of ZnO in polymer matrix, the surface of nanoparticles was modified to organophile with ??-aminopropyltriethoxyl silane. PEA/ZnO BNCs were characterized by Fourier transform infrared spectra, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The FE-SEM, AFM, and TEM results confirmed that the nanoparticles were dispersed uniformly in PEA matrix at the nanoscale. In addition, thermogravimetric analysis data indicated an improvement of thermal stability of novel BNC materials as compared to the pure polymer.     

Preparation of new polymer nanocomposites based on chiral poly(amide-imide)/surface-modified ZnO nanoparticles containing 4,4′-methylene bis(3-chloro-2,6-diethylaniline) linkages via ultrasonication-assisted process

In the present investigation, a novel chiral poly(amide-imide) (PAI) was synthesized via direct polycondensation reaction of chiral diacid monomer with 4,4′-methylene bis(3-chloro-2,6-diethylaniline) in molten tetrabutylammonium bromide as a green solvent. Then PAI-based bionanocomposites (BNC)s have been successfully prepared via ultrasonic irradiation method using zinc oxide (ZnO) nanoparticles functionalized by γ-aminopropyltriethoxysilane as a coupling agent to decrease aggregation of nanoparticles in polymer matrix. The physicochemical and morphology properties of the neat PAI and BNCs were studied using ¹H-NMR, FT-IR spectroscopy, specific rotation, elemental analysis, X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FT-IR and TEM depicted that the ZnO nanoparticles function as a physical cross-linking agent with PAI through hydrogen bonding between the OH on the ZnO nanoparticles and the C=O of the amide and imide groups. Also, TEM and FE-SEM images revealed that ZnO nanoparticles were dispersed in PAI matrix with particle size between 15 and 25 nm. Thermogravimetric analysis data showed an improvement of thermal stability of new BNCs in comparison with the pure PAI.     

Preparation and characterization of transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency

Transparent ZnO/epoxy nanocomposites with high-UV shielding efficiency were reported in this paper. First, zinc oxide (ZnO) precursor was synthesized via the homogeneous precipitation method and ZnO nanoparticles were then made by calcination of the precursor at different temperature. The structural properties of the as-prepared ZnO nanoparticles were studied in detail using thermogravimetry (TGA), differential thermal analysis (DTA), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and transmission electron microscopy (TEM), respectively. Transparent ZnO/epoxy nanocomposites were subsequently prepared from transparent epoxy (EP-400) and as-prepared ZnO nanoparticles via in situ polymerization. Optical properties of ZnO/epoxy nanocomposites, namely visible light transparency and UV light shielding efficiency, were studied using an ultraviolet-visible (UV-vis) spectrophotometer. The optical properties of the as-obtained nanocomposites were shown to depend on ZnO particle size and content. The nanocomposite containing a very low content (0.07% in weight) of ZnO nanoparticles with an average particle size of 26.7 nm after calcination at 350 °C possessed the most optimal optical properties, namely high-visible light transparency and high-UV light shielding efficiency, that are desirable for many important applications.