表面结构对金纳米颗粒催化性能的影响

利用扫描电镜和透射电镜研究了不同形貌的金纳米颗粒的三维结构。高分辨透射电镜观察表明有高能面的纳米颗粒表面有高密度的台阶原子,而表面为低能面的颗粒表面光滑。通过对不同晶粒尺寸,不同表面结构的纳米颗粒的高分辨电镜观察及催化性能的比较和统计,结果显示尺寸大小(比表面积值)对纳米颗粒催化性能的影响不如高能面的影响明显。纳米颗粒的催化性能与表面台阶原子所占的比列(与纳米颗粒总原子数的比值)直接相关。     

CdSe／PVK纳米晶薄膜及其电致发光特性

以巯基乙酸（RSH）为稳定剂，在水溶液中合成CdSe纳米晶，用表面活性剂将分散在水溶液中的纳米颗粒转移到有机溶剂中，与具有电荷输运性能的有机聚合材料复合。作为电致发光（EL）器件的工作层，得到较强的位于600nm附近的CdSe纳米晶的带边发射，以及较弱的位于420nm附近的来自聚合物的发射。器件EL强度首先随着外加电压的增加而增加，当电压超过26V时，EL强度开始下降。器件的电流-电压（I-V）特性基本符合二极管特性，表明器件是受载流子注入限制的。     

碳辅助法制备Mn_3O_4纳米颗粒北大核心

以脱脂棉为碳源,氯化锰为前驱物,采用碳辅助法制备了粒径约为65 nm的Mn3O4纳米颗粒。通过透射电镜（TEM）和高倍透射电镜（HRTEM）对制备样品的形貌、粒径及晶面的结构特性进行了分析;通过X射线衍射（XRD）表征,分别对不同煅烧温度（400-600℃）下样品的物相、晶粒度进行了研究,表明500℃为Mn3O4纳米颗粒的最佳制备温度;X射线光电子能谱（XPS）表征表明制备的Mn3O4表面存在碳元素,N2吸附-脱附曲线测试结果表明Mn3O4纳米颗粒具有较大的比表面积。另外,通过紫外-可见光（UV-vis）吸收表征表明,在一定的波长范围内该Mn3O4纳米颗粒的可见光吸收能力明显增强,有利于提升其光解水制氢能力。     

α和β晶型酞箐酮纳米颗粒的光谱研究

在水溶液中分别对α和β晶型酞菁酮（CuPc）初始粉末进行激光消融制备得到了其相应的纳米颗粒。X射线衍射（XRD）、紫外可见光谱（UV－Vis）和傅立叶变换红外光谱（FT－IR）对其分析表明激光消融前后酞菁铜相应的两种晶型均没有发生变化，说明α和β晶型的酞菁铜在激光消融过程中都是稳定的，激光消融作为制备这两种晶型酞菁铜纳米颗粒的方法是简单有效的。     

脱油沥青溶剂热合成碳包覆纳米金属颗粒

以脱油沥青（DOA）为碳源,二茂铁和两性共聚物P123（P123）分别为催化剂和表面活性剂,在甲苯溶剂中于450℃下反应4h,合成碳包覆纳米金属颗粒（CEMNPs）。用场发射扫描电镜、高分辨透射电镜和X射线衍射对所得产物进行了表征和分析。结果表明：合成了具有核壳结构的碳包覆纳米Fe3O4颗粒,其直径分布在100～300nm之间。研究机理表明产物是在二茂铁的催化作用及表面活性剂P123的组装作用下形成的。     

用于电机发电的氧化锌纳米结构制备及性能研究

选择了均匀沉淀法来制备氧化锌纳米颗粒,用PEG200进行表面改性,使制备的氧化锌纳米颗粒更加分散。利用X-射线衍射（XRD）、扫描电子显微镜（SEM）表征证明了制备样品是粒径约20nm的氧化锌纳米颗粒,结晶性良好、粒径均匀,单个颗粒呈米粒状,颗粒相连呈薄片状。最后通过半导体特性分析仪（Agilent 4156C）和精密阻抗特性分析仪（Agilent 4284A）分别测量了受不同力时的氧化锌纳米颗粒的特性粘度（I-V特性）和阻抗值,并进行分析,得出其力敏特性。     

热丝法制备硅纳晶颗粒及其发光性质

利用热丝化学气相沉积法,在真空腔中通过选择设定不同加热功率的热丝热解硅烷制备出一系列不同颗粒尺寸的硅纳米颗粒样品。透射电镜分析表明硅纳米颗粒具有结晶良好的纳晶结构。通过自然氧化钝化硅纳米颗粒表面,消除表面悬键的影响,使得硅颗粒具有高效的光致发光特性,发光范围在红光到近红外区,发光特性与量子限域效应相吻合。发光寿命测量表明所制备的硅颗粒的发光寿命在微秒量级,并且通过比较不同硅颗粒分布样品中相同发光波长衰减寿命的差异,揭示了所制备样品中硅纳米颗粒之间存在耦合作用。     

磷钨酸乙醇染色法在嗜铬颗粒电镜X射线显微分析中的应用

通过比较常规透射电镜制样法、快速冷冻固定－冷冻超薄切片法及磷钨酸乙醇（EPTA）染色法在嗜铬颗粒透射电镜X射线显微分析中的应用，发现磷钨酸乙醇染色法能使嗜铬颗粒电子着色，从而较好地显示嗜铬颗粒的超微结构。同时磷钨酸乙醇染色法也以在一定程度上原位保留生物样品中元素，可以应用于检测样品元素含量的变化或比较样品元素含量的组间差别，提示磷钨酸乙醇染色法是一种可应用于透射电镜X射线显微分析的经济简便的生物样品制备方法。     

表面化学修饰的氧化锌纳米晶光谱性质

最近我们合成了ZnO－AOT反向胶束体系。（AO，sulfQberasteinsaeur。his－（2－ethrlhexrllesterNatrlum·sak）。在低温热处理下卜SD℃），其光谱特征表现为：与＊＊T修饰前的zno纳米微粒相比，带边激子发射明显增强，且表面缺陷态发光带蓝移。用锌盐与氢氧化物在醇中进行反应，生成Zno醉溶液。高分辨透射电镜成像表明，Zno纳米微粒径约6urn结晶性较好，可见晶格条纹。电子衍射表明ZuO为问锌矿结构且呈多晶态。用反相胶束法把Zno填充到xor反向胶束笼中，在～sooC回流4小时，制成zno－xowi甲苯反向胶束体系。在Uvikon吸收光谱仪和F…     

Ag、Au纳米颗粒的激光表面修饰

通过用Nd：YAG激光（λ=1064nm）对氧化还原法制备的Ag、Au纳米颗粒的修饰，使Ag、Au纳米颗粒的尺寸均匀性得到更好的改善。用透射电子显微镜（TEM）和紫外-可见表面等离于体吸收（SPA）光谱对激光修饰后的Ag、Au纳米颗粒进行了测量和表征，结果表明，这些被修饰过的Ag、Au纳米颗粒由于自身体系发生了改变，可以作为更高效表面增强拉曼光谱（SERS）的增强基底。     

Structural characterization of SiC nanoparticles

The structure and size of SiC nanoparticles were studied by different characterization methods including small angle X-ray scattering (SAXS), transmission electron microscope (TEM), and X-ray diffraction (XRD). The results showed that particle size distributions determined respectively from SAXS and TEM are comparable and follow the log-normal function. The size distribution of the particles is between 10 to 100 nm with most of them being in the range of 20–50 nm. The average particle size is around 42 nm. XRD identifies the phase of the SiC nanoparticles and suggests the average size of the single crystalline domain to be around 21 nm. The combined results from XRD and SAXS suggest the existence of many polycrystals, which is confirmed by the HRTEM observation of particles with twins and stacking faults. The material synthesis methods leading to various particle sizes are also discussed.     

A facile non-organometallic synthesis of hexadecylamine-capped ZnSe nanoparticles

The synthesis of hexadecylamine (HDA)-capped ZnSe nanoparticles via a facile method that is not mediated by organometallic compounds at low temperature is hereby reported. The synthesis involves the addition of an aqueous solution of zinc chloride to a selenide ion solution prepared by the reduction of selenium powder. By varying the reduction time, we studied the size, optical and structural properties of the as-synthesised nanoparticles. The as-synthesised ZnSe nanocrystals were characterised by UV–visible (UV–vis) absorption and PL spectroscopy, transmission electron microcopy (TEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited strong quantum confinement in their optical properties with band-edge luminescence.     

修饰纳米氧化铽溶胶的制备及光学特性研究

以乙酰丙酮(acac)和2,2′-联吡啶(2,2′-bipy)作为修饰剂,用NaOH溶液调节pH值,采用溶胶沉淀法合成得到修饰纳米氧化铽甲醇溶胶。用荧光光谱、紫外-可见光谱和高分辨透射电镜(HRTEM)对纳米氧化铽甲醇溶胶的光学特性和粒子结构进行表征。研究结果表明,被acac和2,2′-bipy修饰的氧化铽甲醇溶胶能在545nm附近发射出很强的Tb3+的特征绿色荧光;透射电镜及选区衍射(SED)结果表明溶胶中的纳米粒子为氧化铽,其平均粒径只有6nm。     

Synthesis and characterization of ceria quantum dots using effective surfactants

The stable and crystalline phase of different surfactants (CTAB, PEG and SDS) capped CeO₂ nanoparticles were directly synthesized by chemical precipitation method at room temperature. The effects of surfactants on the structural and optical properties of nanoparticles are characterized. The optical properties of the nanoparticles were investigated by UV–visible and PL spectroscopy. The effects of surfactants with observed band shifts are due to quantum confinement effect. The optical band gap values are determined by simple energy wave equation and Tauc plot method. The observed particle sizes are very closer to the Bohr exitonic radius. The emission bands such as violet, blue, green and orange are observed in PL spectra. The PL integrated intensity ratio of the UV emission to the deep-level green emission (I_UV/I_DLE) for CTAB, PEG and SDS capped CeO₂ nanoparticles are observed. The XRD measurement shows that CeO₂ has cubic fluorite structure having the particle size 6–10 nm. The lattice strains were detected by Williamson–Hall plot method. The surface morphology of the nanoparticles is studied by SEM and FESEM analysis. TEM images show that the particles are nearly spherical in shape with diameter of 5–10 nm. Using FTIR spectra, the functional groups of the ceria are identified.     

一种制备纳米Fe_3O_4的新方法及其磁性能研究

在正丙醇–水体系中,以NaOH为沉淀剂,用共沉淀法制备了纳米Fe3O4粒子,并用TEM和XRD对其进行了表征。考察了制备过程中工艺参数对Fe3O4颗粒大小的影响,并对影响机理进行了探讨。结果表明:纳米Fe3O4的平均粒径约为15nm;其饱和磁化强度可达73.34Am2/kg,比用水热法(42Am2/kg)和共沉淀法(60Am2/kg)制备的Fe3O4纳米粒子的要高。     

Investigations on the influence of surfactant in morphology and optical properties of zinc oxide nanopowders for dye-sensitized solar cells applications

We studied the influence of the synthesis route on the morphology and optical properties of zinc oxide (ZnO), with applications in dye-sensitized solar cells (DSSCs). For this purpose, we obtained surfactant capped ZnO nanopowders, in the presence of non-ionic surfactants with different structures, and demonstrated their behavior as semiconductors in DSSCs. The ZnO nanopowders and films (obtained from nanopowders using the doctor blading method) were analyzed by transmission electron microscopy (TEM), high resolution TEM (HRTEM), and selected area electron diffraction (SAED). The optical properties were examined by UV, visible spectroscopy, and the band gap energies were calculated using the Tauc equation. The values obtained for DSSCs efficiencies were in good agreement with the characteristics of ZnO, both powders and films, and can be correlated with the synthesis route. The highest efficiency (1.19%) was achieved using ZnO nanopowder capped with Triton X-100, having a mean diameter of ～19 nm. We find that the use of capped ZnO nanoparticles is favorable for DSSCs, possibly because of the good porosity of the film and better dye adsorption. Moreover, the efficiency of the cells is influenced by the surfactant structure, due to the particle morphology.     

Synthesis,characterization and conducting properties of novel poly (vinyl cinnamate)/zinc oxide nanocomposites via in situ polymerization

New polymer nanocomposite based on poly (vinyl cinnamate) (PVCin) with zinc oxide (ZnO) was synthesized by in situ polymerization of vinyl cinnamate with different concentrations of ZnO nanoparticles. The composite was characterized through FT-IR, FT-Raman, UV spectroscopy, XRD, HRTEM, FE-SEM, DSC, TGA and electrical conductivity studies. The IR, Raman and UV spectra ascertained the structural variation of PVCin network by the insertion of nanoparticles within the polymer segment. The morphological studies by TEM and FE-SEM photographs indicate that the nanopowder was uniformly dispersed in the polymer. The presence of nanoparticles in the nanocomposite was clearly observed from the XRD studies and the ordered arrangement of nanoparticles within the macromolecular chain of PVCin increased with increase in concentration of nanofillers. DSC results showed that the glass transition temperature and crystalline melting point were increased smoothly with the increase in concentration of nanoparticles. Analysis of TGA studies showed a significant increase in thermal stability with an increase in weight percentage of nanoparticles. The DC conductivity of nanocomposite was increased by ten orders of magnitude with the addition of 7 wt% of nano ZnO inclusion. AC conductivity, dielectric constant and dielectric loss tangent of nanocomposite was remarkably increased with increase in ZnO content up to 7 wt% of filler particles. Both AC and DC conductivity and dielectric properties were decreased beyond 7 wt% loading.     

Structural,Optical, and Electrical Properties of Cobalt-Doped CdS Quantum Dots

In the present work, a systematic study has been carried out to understand the influence of cobalt (Co) doping on various properties of CdS nanoparticles. CdS and Co-doped CdS quantum dots have been prepared at room temperature using a chemical precipitation method without using catalysts, capping agents, or surfactants. X-ray diffraction reveals that both undoped and Co-doped CdS nanoparticles exhibit hexagonal structure without any impurity phase, and the lattice constants of CdS nanoparticles are observed to decrease slightly with increasing cobalt concentration. High-resolution transmission electron microscopy (HRTEM) shows that the particle size of CdS and 5.02% Co-doped CdS nanoparticles is in the range of 2 nm to 4 nm. The Raman spectra of Co-doped CdS nanoparticles exhibit a red-shift compared with that of bulk CdS, which may be attributed to optical phonon confinement. The optical absorption spectra of Co-doped CdS nanoparticles also exhibit a red-shift with respect to that of CdS nanoparticles. The electrical conductivity of CdS and Co-doped CdS nanoparticles is found to increase with increasing temperature and cobalt concentration.     

Nanodiamond Glass with Rubber Bond in Natural Rubber

Nanodiamond glass is an amorphous solid consisting of nanodiamond as a nanoparticle. The several‐nm‐space between the nanodiamonds is filled with a medium that reversibly deforms and recovers. Hence, nanodiamonds linked in the medium are arranged in several‐nm intervals. To prepare the nanodiamond glass, nanodiamonds are dispersed as inorganic nanoparticles with highly reactive functional groups into natural rubber as an incompressible medium exhibiting reversible deformation and recovery. Nanodiamond glass can be distinguished from nanodiamond‐filled rubber, which exhibits ordinary entropic elasticity. Natural rubber particles dispersed in water (i.e., latex) are used to prepare nanodiamond glass, chemically embed nanodiamonds onto the surface of the natural rubber particles, and subsequently attach the surfaces together to achieve close packing of the nanodiamonds. Increasing the modulus of natural rubber constrained in the nanospaces ensures the energetic elasticity of nanodiamond glass. This work demonstrates that nanodiamond glass with energetic elasticity is a new research field.     

温度控制对ATO纳米分散液水热生长的影响

以SnCl4·5H2O和SbCl3的共沉淀氢氧化物为原料,在水热过程中采用温度控制、分段加热的方法,制备了单分散的ATO纳米分散液。用XRD、TEM、X射线能量散射谱(EDS)和压片测电阻等方法,对ATO纳米粉进行了表征。结果表明:温度控制、分段加热的水热法,可以一步合成粒径为10~15nm,高比表面积、分散性好的ATO纳米晶导电粉体,在低温短时的条件下,同时实现了氧化物的掺杂和分散。并对生长机理做了初步探讨。