共查询到20条相似文献,搜索用时 140 毫秒
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ZnS超微粒有序组装体系制备与结构研究 总被引:5,自引:0,他引:5
用LB膜技术在石英及CaF2衬底上沉积二十二酸锌Y型多层膜,低压(66.7Pa)下与H2S气体反应,红外,可见紫外吸收光谱及X衍射结果表明,反应前后LB膜仍保持良好的有序性,反应后生成的ZnS超微粒子以“三明治”结构存在,并观察到这种ZnS纳米微粒以单分子膜状态存在。 相似文献
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用LB方法在电沉积CdS薄膜上修饰了PcCu单分子膜,并利用表面光电压谱对CdS薄膜与PcCu修饰的CdS薄膜进行了测试。结果表明,修饰后的CdS薄膜其表面光电压值提高约50倍,并且光电压响应由300-500nm扩展为300-700nm。紫外-可见偏振光谱测试表明,LB膜中酞菁环的取向角为45度。 相似文献
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CdS/ZnS包覆结构纳米微粒的微乳液合成及光学特性 总被引:6,自引:0,他引:6
利用微乳液法合成CdS纳米微粒,并对其进行表面修饰,得到具有CdS/ZnS包覆结构的纳米微粒,以及收光谱与透射电镜表征其粒度与包覆结构,得到CdS内核的直径为5nm,CdS/ZnS包覆结构总粒径为8~10nm,吸收阈值及发射峰的蓝移起因于量子限域效应,并观测到ZnS的懈覆经CdS纳米微粒的表面态发射、增强带边发射1并使带边发射进一步蓝移。 相似文献
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纳米粒子的自组装和有序组装膜的结构与性质近年来受到了人们的广泛关注,纳米粒子的表面结构与性质对由其组装成的有序膜的结构与性质有直接的影响。文章报道了利用自组装技术制备的银纳米粒子与双亲有机分子的单层和多层复合LB膜,通过吸收光谱和表面增强拉曼光谱研究了银纳米粒子与吸附分子间的相互作用,探讨了复合膜的成膜特性及银纳米粒子的拉曼增强特性。十八胺/银粒子复合LB膜的吸收光谱及拉曼光谱显示,十八胺分子与银纳米粒子表面的活位通过NH2中的氮原子以复合体的形式结合;同时,在激发光的作用下复合体可能存在光催化过程。根据银粒子复合LB膜的实验结果,十八胺和十八酸之间的反应产物在复合膜中起空间位阻作用,与银粒子表面的相互作用较弱。 相似文献
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核壳结构CdS/ZnS纳米微粒的制备与光学特性 总被引:6,自引:0,他引:6
用微乳液法制备CdS纳米微粒 ,以ZnS对其进行表面修饰 ,得到具有核壳结构的CdS/ZnS纳米微粒 .采用X射线衍射 (XRD)、透射电镜 (TEM )表征其结构、粒度和形貌 ,紫外 可见吸收光谱 (UV)、光致发光光谱(PL)表征其光学特性 .制得的CdS近似呈球形 ,直径为 3.3nm ;以XRD和UV证实了CdS/ZnS核壳结构的实现 .研究了不同ZnS壳层厚度对CdS纳米微粒光学性能的影响 ,UV谱表明随着壳层厚度的增加纳米微粒的吸收带边有轻微的红移 ,同时短波吸收增强 ;PL谱表明壳层ZnS的包覆可减少CdS纳米微粒的表面缺陷 ,带边直接复合发光的几率增大 ,具有合适的壳层厚度时发光效率大大提高 . 相似文献
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Erik D. Spoerke Bridget A. Connor Dara V. Gough Bonnie B. McKenzie George D. Bachand 《Particle & Particle Systems Characterization》2014,31(8):863-870
This paper describes the use of microtubules (MTs) as nanoscale templates for the biologically directed growth and assembly of cadmium sulfide (CdS) nanotubes. CdS is a wide bandgap semiconductor with valuable optical, electronic, and chemical properties, and the organization of CdS nanostructures is critical to their widespread utility. The present work explores a bioinspired, biomediated approach to the formation and assembly of CdS nanotubes. In particular, a biomimetic synthetic strategy is used to control the uniform growth of cubic zinc blende CdS nanocrystals on MT templates, replicating the MTs' tubular morphology with dense CdS only a single nanocrystal thick. Furthermore, specific interactions between MTs and functional microtubule‐associated proteins (MAPs) are exploited to manipulate the secondary organization of these MT templates. The subsequent directed growth of CdS nanotubes on these structures produces specific biomediated architectures including linear arrays, 3D asters, and rings. Finally, cathodoluminescence from MT‐templated CdS structures verifies that the valuable semiconducting character of these materials is exhibited. These demonstrations of nanoscale materials synthesis and assembly illustrate a new level of complexity and control over materials synthesis that may be achieved using such biological tools and processes. 相似文献
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通过对不同制膜条件下样品的π-A曲线及紫外-可见吸收光谱的测量,研究LB单分子层膜中半花菁衍生物(hemicyaninederivative简称HD)分子的聚集状态及其形成机制。纯半花菁衍生物单分子层膜中分子以H聚集体的形式存在导致吸收峰的兰移及有效分子二阶非线性极化率β(基频波长λ=1.064μm)的减小。实验表明聚集体的形成主要发生在压膜过程。提高压膜速度或降低压膜终极压力(拉膜压力)可显著减小分子的聚集程度,从而提高单分子层膜的光学非线性极化率。 相似文献
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首次合成了一种称之为聚苯乙烯芪盐的有机高分子材料.此材料可以在水面上形成稳定的单分子层膜,并且所形成的单分子层膜可以转移到固体衬底上去.对聚苯乙烯芪盐单分子层膜进行光学二次谐波产生测量,得到聚苯乙烯芪盐对应于每个发色团的二阶非线性极化率为1.2×10~(-28)esu.制备了该材料两种不同类型的多层膜,讨论了多层膜二次谐波产生信号不随层数增加而增加的可能原因. 相似文献
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Photocatalytic Oxidation of Hydrosulfide Ions by Molecular Oxygen Over Cadmium Sulfide Nanoparticles
Photocatalytic activity of CdS nanoparticles in hydrosulfide-ions air oxidation was revealed and thoroughly investigated. HS− photooxidation in the presence of CdS nanoparticles results predominantly in the formation of SO3
2− and SO4
2− ions. Photocatalytic activity of ultrasmall CdS crystallites in HS– photooxidation is much more prononced as compared to bulk CdS crystals due to high surface area of nanoparticles, their negligible light scattering, improved separation of photogenerated charge carriers etc. It was shown that hydrosulfide ions can be oxidized in two ways. The first is HS− oxidation by the CdS valence band holes. This process rate depends on the rate of comparatively slow reaction between molecular oxygen and CdS conduction band electrons. The second reaction route is the chain-radical HS− oxidation induced by photoexcited CdS nanoparticles and propagating in the bulk of a solution. In conditions favourable to chain-radical oxidation of HS−(i.e. at low light intensities and CdS concentration and high oxygen and Na2S concentrations) quantum yields of the photoreaction reach 2.5. 相似文献
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Abstract Raman and far infrared spectra (in the frequency range 20–360 cm?1) have been recorded for polycrystalline samples of six crystals having the cadmium iodide layered structure. The four fundamental zone-center vibrational frequencies are assigned for CoBr2, FeBr2, MgBr2, MnBr2, CdI2 and MgI2. Values of the principal interlayer force constants are deduced from a simple linear chain dynamical model, and comparisons are made with recent results from spectroscopic studies of crystals with the related cadmium chloride structure. 相似文献