ZnO/ZnS核/壳纳米结构的形态及其演变模式

用两步生长的方法在醋酸锌和六亚甲基四胺水溶液中生长ZnO纳米棒阵列,然后以ZnO纳米棒阵列为模板,在Na2S水溶液中硫化0.5～6 h形成ZnO/ZnS纳米结构.用XRD,SEM和TEM表征了ZnO/ZnS核/壳纳米结构的晶体结构、表面形貌.研究了ZnO/ZnS核/壳纳米结构的形态及其转变的模式.在硫化过程中,ZnO首先形成ZnO/ZnS核/壳纳米棒,随着硫化程度的增强,核/壳结构顶部出现空洞,空洞扩展形成管状结构,进一步硫化,管状结构坍塌.硫化形成的ZnO/ZnS结构的形态不仅依赖于初始纳米棒的直径大小和硫化时间的长短,还依赖于纳米棒的分布密度.     

ZnO-Ni壳核丝状阴极的制备及其场发射性能研究

采用水热法在金属镍(Ni)丝表面生长氧化锌(ZnO)纳米材料.通过改变生长条件,制备出花状、锥状、管状、棒状四种形貌的ZnO-Ni壳核丝状阴极.采用扫描电子显微镜(SEM)观察所制备丝状阴极的表面形貌,采用X射线衍射(XRD)分析仪进行物相分析,结果表明所生长的纳米ZnO具有(002)品面择优取向.测试比较了这四种形貌ZnO-Ni壳核丝状阴极的场发射性能,结果表明管状ZnO纳米材料能较好地改善阴极表面的微观形貌,提高了阴极的场增强效应.     

ZnS:Eu/ZnS核/壳结构量子点自发辐射性能研究

利用水溶性前驱体材料在水性介质中制备了ZnS:Eu和ZnS:Eu/ZnS核/壳结构量子点,并利用XRD、TEM和PL对ZnS:Eu和ZnS:Eu/ZnS核/壳结构量子点的结构和发光性能进行了研究.ZnS:Eu和ZnS:Eu/ZnS量子点XRD谱显示:ZnS:Eu和ZnS:Eu/ZnS量子点具有β-ZnS结构,且随着Zn...     

衬底退火温度对ZnO纳米结构形貌和发光特性的影响

利用热蒸发Zn粉的方法,在Au/掺铝氧化锌(AZO) /石英衬底上生长ZnO纳米结构。为了研究不同 温度退火后的衬底对生长的ZnO纳米结构的影响,Au/AZO/石英衬底在生长纳米结构前分别在 300、500和700℃真空下退火。Au/AZO/石英衬底的表面形貌用原子力显微镜(AFM)观测 。ZnO纳米结构的微结构、形貌和 光学性能分别用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和荧光光 谱仪进行测量。结果表明,在未退火和300 ℃ 退火衬底上生长了大量的ZnO纳米棒,而在500℃退火衬底上沉积了大量ZnO纳米颗粒。单晶结构 的纳米棒的平均直径分别约50nm,其 生长机制为蒸气-液体-固体(VLS)生长机制。荧光光谱显示所有的样品 都存在紫外发光峰和深能级发射带,随着退火温度的升高,生长的纳米结构的紫外发光峰相 对强度增强,而深能级发射强度减弱。     

ZnO纳米棒的低温生长及光致发光性能

采用化学溶液沉积法在ITO导电玻璃上制备近一维ZnO纳米棒.利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)对样品进行表征,研究了不同Zn2+摩尔浓度和不同生长时间对样品的结构、形貌和光致发光性能的影响.结果表明,所制备的ZnO纳米棒为纤锌矿结构并沿c轴择优取向生长.另外,随着Zn2+摩尔浓度的增加,纳米棒的直径增大.当Zn2+摩尔浓度为0.1M时,ZnO纳米棒的直径和长度都随生长时间的增加而增加.PL测试表明,样品均具有良好的发光性能,并且ZnO纳米棒的结晶质量随着Zn2+摩尔浓度和生长时间的增加均有所提高.     

SnS壳层厚度对ZnO/SnS核壳结构纳米棒光致发光性能的影响

通过简单的水热法制备了ZnO纳米棒,然后成功地在ZnO纳米棒上修饰了一层SnS壳层,形成了ZnO/SnS核壳结构纳米棒。利用X射线衍射、扫描电子显微镜和透射电子显微镜对上述核壳结构进行了表征。结果表明制备的ZnO纳米棒直径在20~200nm,长度达1μm,随着SnS壳层修饰时间的增加壳层厚度逐渐增加。PL分析表明,当SnS壳层厚度很薄时,由于ZnO纳米棒表面态得到了修复,ZnO纳米棒的PL强度得到了很好的提升;但当SnS壳层厚度达到一定程度后,该核壳结构会形成一种Ⅱ型能带排列,这样该核壳结构的PL强度反而会被降低。     

核/壳结构ZnS:Mn/ZnS量子点光发射增强研究

利用水溶性前驱体材料在水性介质中制备了ZnS:Mn和ZnS:Mn/ZnS核/壳结构量子点(QDs,quantum dots),并用X射线衍射(XRD)、光致发光(PL)对ZnS:Mn和ZnS:Mn/ZnS核/壳结构QDs的结构和发光性能进行研究.ZnS:Mn和ZnS:Mn/ZnS QDs XRD谱与标准谱吻合,根据De...     

花状纳米结构ZnS:Cu的制备与光学性质研究

采用水热法合成了具有花状纳米结构的ZnS:Cu粉末.利用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)和荧光光谱仪研究了在不同正硅酸四乙酯(TEOS)含量的条件下制备的样品的物相、形貌与光致发光(PL)性质.测试结果表明:制备的ZnS:Cu样品都具有立方相闪锌矿结构;由于TEOS分子...     

ZnO纳米棒的低温生长及光致发光性能

采用化学溶液沉积法在ITO导电玻璃上制备近一维ZnO纳米棒. 利用X射线衍射（XRD) 、扫描电子显微镜（SEM）和光致发光谱（PL）对样品进行表征,研究了不同Zn2+摩尔浓度和不同生长时间对样品的结构、形貌和光致发光性能的影响. 结果表明,所制备的ZnO纳米棒为纤锌矿结构并沿c轴择优取向生长. 另外,随着Zn2+摩尔浓度的增加,纳米棒的直径增大. 当Zn2+摩尔浓度为0.1M时,ZnO纳米棒的直径和长度都随生长时间的增加而增加. PL测试表明,样品均具有良好的发光性能,并且ZnO纳米棒的结晶质量随着Zn2+摩尔浓度和生长时间的增加均有所提高.     

电沉积工艺制备纳米ZnO及其生长机理

本文以Zn（NO3）2·6H2O和KCl的水溶液为电解液,采用三电极恒电位体系在ITO上电沉积制备了形貌可控的纳米ZnO。通过旋转涂布（CH3COO）2Zn·2H2O溶液,煅烧后可在ITO表面生长一层ZnO种子层。该种子层可以增加ZnO的密度,使c轴取向更加明显。通过场发射扫描电子显微镜（ FESEM）、X射线衍射（ XRD）、光致发光光谱（PL）等测试手段,系统地分析了电沉积参数（Zn（NO3）2·6H2O浓度、电沉积电压、电沉积温度）对电沉积制备纳米ZnO形貌、结构、光催化性能、发光性能的影响,并研究了其生长机理。     

ZnO纳米棒水热法制备及其发光特性研究

采用氢氧化钾(KOH)和二水醋酸锌(Zn(CH3COO)2.2H2O)配制不同浓度的反应溶液,反应过程中加入表面活性剂聚乙二醇(HO(CH2CH2O)13H),在80℃水热反应条件下制备出了优异的ZnO纳米材料。采用扫描电镜(SEM)、X射线衍射(XRD)、荧光光谱仪等测试方法研究了样品的成分、表面形貌和微结构。SEM研究结果显示:样品沿c轴择优生长,径粒分布均匀,长径比高,为六方纤锌矿结构的ZnO纳米棒和菊花状ZnO纳米棒。光致发光谱性能分析显示样品在392 nm附近具有很强的紫外光发射能力,随着反应物浓度的增加,紫外峰发生约3 nm的蓝移,同时,样品还在绿光535 nm附近有较弱的光致发光现象。以上结果表明所制备的ZnO纳米材料具有优异的紫外光发射能力。     

以ZnS为源用化学气相沉积法在硅衬底上生长ZnO纳米颗粒

首次以ZnS为源,采用化学气相沉积法在抛光的Si单晶片衬底上生长晶态的ZnO纳米颗粒,其形貌、尺寸和密度都与气体流量、衬底温度、生长时间以及有无催化剂等生长条件密切相关．在没有Au催化的条件下,ZnO颗粒呈圆形颗粒,直径多在30-200nm之间,密度为10^4-10^9cm^-2;有Au催化的条件下,ZnO纳米颗粒呈六边形,平均尺寸明显变小,在10—100cm之间,而密度显著提高,为10^8-10^10cm^-2所制备的纳米ZnO颗粒在497nm和376nm附近分别有很强和较弱的光致发光．     

ZnO Hierarchical Micro/Nanoarchitectures: Solvothermal Synthesis and Structurally Enhanced Photocatalytic Performance

A novel ZnO hierarchical micro/nanoarchitecture is fabricated by a facile solvothermal approach in an aqueous solution of ethylenediamine (EDA). This complex architecture is of a core/shell structure, composed of dense nanosheet‐built networks that stand on a hexagonal‐pyramid‐like microcrystal (core part). The ZnO hexagonal micropyramid has external surfaces that consist of a basal plane (000 ) and lateral planes {0 11}. The nanosheets are a uniform thickness of about 10 nm and have a single‐crystal structure with sheet‐planar surfaces as {2 0} planes. These nanosheets interlace and overlap each other with an angle of 60° or 120°, and assemble into a discernible net‐ or grid‐like morphology (about 100 nm in grid‐size) on the micropyramid, which shows a high specific surface area (185.6 m² g^?1). Such a ZnO micro/nanoarchitecture is new in the family of ZnO nanostructures. Its formation depends on the concentration of the EDA solution as well as on the type of zinc source. A two‐step sequential growth model is proposed based on observations from a time‐dependent morphology evolution process. Importantly, such structured ZnO has shown a strong structure‐induced enhancement of photocatalytic performance and has exhibited a much better photocatalytic property and durability for the photodegradation of methyl orange than that of other nanostructured ZnO, such as the powders of nanoparticles, nanosheets, and nanoneedles. This is mainly attributed to its higher surface‐to‐volume ratio and stability against aggregation. This work not only gives insight into understanding the hierarchical growth behaviour of complex ZnO micro/nanoarchitectures in a solution‐phase synthetic system, but also provides an efficient route to enhance the photocatalytic performance of ZnO, which could also be extended to other catalysts, such as the inherently excellent TiO₂, if they are of the same hierarchical micro/nanoarchitecture with an open and porous nanostructured surface layer.     

Microstructural and photoluminescence properties of Co-doped ZnO films fabricated using a simple solution growth method

Nanocrystalline 2% cobalt doped ZnO films were successfully prepared using a simple chemical solution method on glass substrates and subsequently annealed in air at 300 and 500 °C. Structural, morphology, chemical composition and photoluminescence properties of the films were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and Fourier transform infra-red spectroscopy (FTIR) and photoluminescence (PL) spectroscopy. X-ray diffraction studies of the annealed films reveal the formation of polycrystalline hexagonal wurtzite structure of ZnO crystals without any co-related secondary phases. SEM micrographs of the films show the formation of spherical nanoparticles. Photoluminescence of the films showed a weak UV and defect related visible emissions like blue, blue–green, yellow and relatively intense orange–red emissions and their mechanism was discussed in detail.     

Highly sensitive and selective ethanol sensors based on flower-like ZnO nanorods

A simple and easy hydrothermal process has been employed to synthesize flower-like ZnO products consisting of numerous orderly oriented and bundled nanorods.The structure and morphology of the novel ZnO structure are characterized in detail.The flower-like ZnO-nanorod-based gas sensors are investigated for their ethanoi-sensing properties,and the results reveal that the sensors exhibit a high response of 143.6 to 1000 ppm ethanol and good selectivity at the optimal operating temperature of 250℃.The effect of the flower-like morphology on the response of the gas sensors to ethanol is also investigated.     

冰乙酸在超声喷雾热分解法制备ZnO薄膜中的作用

采用超声喷雾热分解技术(USP),以二水醋酸锌(Zn(CH<,3>COO)<,2>·2H<,z>O)为原材料.在无碱玻璃衬底上制备了ZnO薄膜.对前驱液pH值、ZnO薄膜结构特性、表面形貌、电学和光学特性的研究结果表明,冰乙酸对ZnO薄膜生长速率具有重要影响.X射线衍射(XRD)和扫描电子显微镜(SEM)测试显示,所有...     

水浴法制备形貌可控的一维ZnO纳米和微米棒

用一步或两步简单的化学溶液法,以醋酸锌为原料,六亚甲基四胺或三乙醇胺为催化剂在玻璃衬底上生长出不同形貌的纳米和微米ZnO棒.探讨了反应液的酸碱度和反应液浓度对生成的ZnO棒形貌的影响,并分析了其生长机制.随着溶液浓度的增加,棒的长度与直径比减小,同时玻璃衬底上生长的ZnO棒从无序分布趋于垂直于衬底平行取向分布.随着pH值的改变,棒的形状由在弱酸性溶液中的细长棒状变为在弱碱性溶液中的圆头对称短棒;当碱性增大到一定程度时,可以生成颗粒状.通过控制一定的酸碱度和溶液浓度,可以得到规则的六角ZnO棒状阵列.测量了样品的XRD和扫描电镜像,并对其发光性能进行了测量分析.其中规则有序六角棒的发光光谱表明峰值在530nm,半高宽为220nm,可能是Vo 的电子和价带中的空穴辐射复合所致.     

Effects of reaction time on the morphological,structural, and gas sensing properties of ZnO nanostructures

Morphological transformation was achieved from ZnO hexagonal needle-like rods to hexagonal flower-like rods by varying the reaction growth time using the hydrothermal method. Optical bandgap energies were calculated from the absorption spectra using UV‐vis spectroscopy. Gas sensing properties of flower-like hexagonal ZnO structures at 50 ppm for ethanol (C₂H₅OH) and nitrogen dioxide (NO₂) at different temperatures were analyzed. The sensor showed a higher response toward C₂H₅OH than NO₂ gas at 350 °C.