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81.
掺杂CdS超微粒的ZrO2薄膜的光学性质 总被引:4,自引:0,他引:4
研究了用溶胶凝胶方法制备的CdS超微粒 ZrO2 薄膜的发光特性 ,测量了不同退火温度处理的样品的荧光光谱、荧光激发光谱和荧光衰减曲线的变化 ,通过荧光衰减曲线研究了 14 0 ps左右的CdS的带间跃迁发射和较慢的表面态发射。还测量了这种掺有CdS超微粒的ZrO2 薄膜的飞秒光克尔效应 ,得到三阶非线性光学极化率为4 4× 10 - 1 1 esu和大约 10 0fs的响应时间。结果表明 ,这类材料具有较大的光学非线性和快速的响应时间 ,在高速光开关等方面有潜在的应用前景 相似文献
82.
Blue-emitting colloidal CdS nanocrystals have been synthesized through the solvothermal reaction of cadmium acetate and thiourea
in N,N-dimethylformamide using poly(ethylene oxide; PEO) as the stabilizing polymer. The as-prepared CdS colloids were stable at
ambient conditions for several weeks. The PEO-stabilized CdS colloids showed a narrow fluorescence band with the maximum at
about 420 nm and thus emitting blue fluorescence under the ultraviolet (UV) lamp. A common red shift of fluorescence band
is not detected for the prepared CdS colloids in the study, indicating that PEO-stabilized CdS NCs possess few crystalline
defects on their surface. In addition, transmission electron microscope micrographs reveal that the sizes of CdS NCs are between
4.4 to 5.4 nm with small standard deviations from 0.5 to 0.7 nm. The particle growth kinetics was studied by monitoring UV-visible
absorption onsets versus the reaction time and was found to nearly follow the Lifshitz–Slyozov–Wagner theory for the Ostwald
ripening mechanism. 相似文献
83.
李春霞 《原子与分子物理学报》2007,24(5):1060-1064
基于密度泛函理论(DFT)的第一性原理方法(DMOL3程序),在广义梯度近似(GGA)下,计算了中小尺寸II~VI族(CdS)n和(CdTe)n团簇的基态结构、最高占据轨道(HOMO)和最低未占据轨道(LUMO)的能隙、结合能等,比较了(CdS)n和(CdTe)n两种团簇的基态结构,能隙与结合能随尺寸变化关系的差异等. 相似文献
84.
We have developed an analytical method to detect adenosine-5′-triphosphate (ATP) and alkaline phosphatase (ALP) based on the generation of CdS quantum dots (QDs). We demonstrated that Cd2+ cation reacts with S2− anion to generate fluorescent CdS QDs in the presence of some certain amount of ATP. With increase in the ATP concentration, the fluorescence intensity of CdS QDs was also enhanced. ATP can be converted into adenosine by the dephosphorylation of ALP, so that the generation of CdS QDs would be inhibited in the presence of ALP. Therefore, this novel analysis system could be applied to assay ATP and ALP based on the growth of fluorescent CdS QDs. 相似文献
85.
We report that sodium alginate and its graft-copolymers with (2-dimethylaminoethyl) methacrylate may attach to the surface of colloidal CdS-thioglycerol quantum dots (QDs) via a ligand exchange process and result in water-soluble and highly stable QD supramolecules. Optical properties of modified QDs in water showed that the emission intensity of QDs was still high after surface passivation. 相似文献
86.
Yuying Huang Fengqiang Sun Tianxing Wu Zhong Huang Zihe Zhang 《Journal of solid state chemistry》2011,184(3):644-58
CdS hollow microspheres have been successfully prepared by a photochemical preparation technology at room temperature, using polystyrene latex particles as templates, CdSO4 as cadmium source and Na2S2O3 as both sulphur source and photo-initiator. The process involved the deposition of CdS nanoparticles on the surface of polystyrene latex particles under the irradiation of an 8 W UV lamp and the subsequent removal of the latex particles by dispersing in dichloromethane. Photochemical reactions at the sphere/solution interface should be responsible for the formation of hollow spheres. The as-prepared products were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Such hollow spheres could be used in photocatalysis and showed high photocatalytic activities in photodegradation of methyl blue (MB) in the presence of H2O2. The method is green, simple, universal and can be extended to prepare other sulphide and oxide hollow spheres. 相似文献
87.
This work demonstrated the feasibility of detecting hydrocortisone in cosmetics using a novel CdSe/CdS quantum dots‐based competitive fluoroimmunoassay with magnetic core/shell Fe3O4/Au nanoparticles (MCFN) as solid carriers. Hydrocortisone antigen was labeled with the synthesized core/shell CdSe/CdS quantum dots (QDs) to form the antigen‐QDs conjugate. Meanwhile, hydrocortisone antibody was incubated with MCFN and the immobilized antibody was obtained. The immobilized antibody was then mixed sequentially with hydrocortisone and a slightly excess amount of the QDs‐labeled hydrocortisone antigen, allowing their competition for binding with the antibody immobilized on MCFN. The bound hydrocortisone and the antigen‐QDs conjugates on MCFN were removed subsequently after the mixture was applied to a magnetic force. The analyte concentration was obtained by measuring the fluorescence intensity of the unbound hydrocortisone antigen‐QDs conjugates. The proposed method was characterized by simplicity, rapidity, and high sensitivity with a wide linear working range of 0.5 to 15000 pg·mL?1 and a low detection limit of 0.5 pg·mL?1. The proposed method was successfully applied to the determination of hydrocortisone in cosmetics with satisfactory results. 相似文献
88.
In this work, CdS sensitized TiO2 nanotube arrays (CdS/TiO2NTs) electrode was synthesized with the CdS deposition on the highly ordered titanium dioxide nanotube arrays (TiO2NTs) by sequential chemical bath deposition method (S‐CBD). The as‐prepared CdS/TiO2NTs was characterized by field‐emission scanning electron microscopy (FE‐SEM) and X‐ray diffraction (XRD). The results indicated that the CdS nanoparticles were effectively deposited on the surface of TiO2NTs. The amperometric I‐t curve on the CdS/TiO2NTs electrode was also presented. It was found that the photocurrent density was enhanced significantly from 0.5 to 1.85 mA/cm2 upon illumination with applied potential of 0.5 V at the central wavelength of 253.7 nm. The photoelectrocatalytic (PEC) activity of the CdS/TiO2NTs electrode was investigated by degradation of methyl orange (MO) in aqueous solution. Compared with TiO2NTs electrode, the degradation efficiencies of CdS/TiO2NTs electrode increased from 78% to 99.2% under UV light in 2 h, and from 14% to 99.2% under visible light in 3 h, which was caused by effective separation of the electrons and holes due to the effect of CdS, hence inhibiting the recombination of electron/hole pairs of TiO2NTs. 相似文献
89.
90.
We describe the construction of a simple but versatile single-beam spectrophotometer that uses no sample holder at all; one arm of a bifurcated fiber optic bundle illuminates the specimen, while the other receives the remitted light. Though designed with an eye to recording the diffuse reflection spectra of scattering-and-absorbing substances, it can also be used for conventional studies (ie transmission spectroscopy) by merely placing a plane mirror behind the cuvette. The performance of the instrument is evaluated and representative spectra of several powders, solutions, and biomaterials are presented. 相似文献