879 resultados para CDS returns
Resumo:
Hybrid organic/inorganic white light-emitting diodes (LEDs) were fabricated of semiconductor polymer poly(N-vinylcarbazole) (PVK) doped with CdSe/CdS core-shell semiconductor quantum dots (QDs). The device, with a structure of indium-tin-oxide (ITO)vertical bar 3,4-polyethylene-dioxythiophene- polystyrene sulfonate (PEDOT:PSS)vertical bar PVK:CdSe/CdS vertical bar Al, emitted a pure white light spanning the whole visible region from 400 to 800 nm. The Commission Internationale del'Eclairage coordinates (CIE) remained at x = 0.33, y = 0.34 at wide applied voltages. The maximum brightness and electroluminescence (EL) efficiency reached 180 cd m(-2) at 19 V and 0.21 cd A(-1) at current density of 2 mA cm(-2), respectively. The realization of the pure white light emission is attributed to the incomplete energy and charge transfer from PVK to CdSe/CdS core-shell QDs.
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A new solvothermal route has been developed for synthesizing the size-controlled CdSe nanocrystals with relatively narrow size distribution, and the photoluminescence (PL) quantum yields (QYs) of the nanocrystals can reach 5-10%. Then the obtained CdSe nanocrystals served as cores to prepare the core/shell CdSe/CdS nanocrystals via a two-phase thermal approach, which exhibited much higher PL QYs (up to 18-40%) than the CdSe core nanocrystals. The nanocrystal samples were characterized by ultraviolet-visible (UV-vis) absorption spectra, PL spectra, wide-angle Xray diffraction (WAXD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM).
Resumo:
CdS nanocrystals were synthesized through AOT/heptane/H2O reverse micelles. New stable reverse mikelles were obtained by adding an appropriate amount of acrylic. acid monomer, CdS nanocrystal-poly(acrylic acid) composites were synthesized by gamma-radiation with a reverse mi'celle route at room temperature. The US nanocrystals with narrow size distribution were, found to be dispersed homogeneously in the poly(acrylic acid) matrix. (C) 2002 Elsevier Science B.V. All rights reserved.
Resumo:
Mixed monolayer films of octadecylamine (ODA) and oligo-DNA were prepared by Langmuir-Blodgett technique and the monolayer films were used as template to direct the formation of different CdS nanostructures. It was found that CdS nanowire was observed when the monolayer film prepared at low surface pressure was used as template, and aggregate of CdS spheres was obtained when the monolayer film deposited at high surface pressure was used as template.
Resumo:
利用Langmuir Blodgett技术制备了十八胺 (ODA) /十聚腺嘌呤 (oligo A10 )单分子膜 ,并以其为模板制备了不同形状的CdS纳米结构 .结果表明以在低膜压下转移的寡聚DNA单层膜为模板可诱导生成线形的CdS纳米结构 ,而以在高膜压下转移的寡聚DNA单层膜为模板得到的是CdS的球形结构聚集体.
Resumo:
The TiO2 nanoparticle thin films have been sensitized in situ with CdS nanoparticles. The SPS measurement showed that large surface state density was present on the TiO2 nanoparticles and the surface state can be efficiently decreased by sensitization as well as selecting suitable heat treatment, Both the photocurrent response and the charge recombination kinetics in TiO2 thin films were strongly influenced by trapping/detrapping of surface states. The slow photocurrent response of TiO2 nanoparticulate thin films upon the illumination was attributed to the trap saturation effects, The semiconductor sensitization made the slow photoresponse disappeared and the steady-state photocurrent value increased drastically, which suggested that the sensitization of TiO2 thin films with CdS could get a better charge separation and provide a simple alternative to minimize the effect of surface state on the photocurrent response.
Resumo:
总结了CdS半导体纳米微粒的复合与组装,并介绍了其应用方面的研究。
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采用 LB膜技术制备了表面活性剂包埋的硫化镉纳米粒子多层膜 ,并利用傅里叶红外光谱、X射线光电子能谱、原子力显微镜和小角 X射线衍射对其结构进行了表征。结果表明制成的 Cd S纳米粒子 LB膜为准一维超晶格
Resumo:
Surface photovoltage spectra (SPS) measurements of TiO2 show that a large surface state density is present on the TiO2 nanoparticles and these surface states can be efficiently decreased by sensitization using US nanoparticles as well as by suitable heat treatment. The photoelectrochemical behavior of the bare TiO2 thin film indicates that the mechanism of photoelectron transport is controlled by the trapping/detrapping properties of surface states within the thin films, The slow photocurrent response upon the illumination can be explained by the trap saturation effect. For a TiO2 nanoparticulate thin film sensitized using US nanoparticles, the slow photocurrent response disappears and the steady-state photocurrent increases drastically, which suggests that photosensitization can decrease the effect of surface states on photocurrent response.
Resumo:
本文阐述了利用紫外可见分光光度法检测CdS薄膜光学性质的基本原理,设计了测试系统,并利用所设计的系统对化学水浴法沉积CdS薄膜的光谱透过率进行测试。通过对不同沉积时间的CdS薄膜的光学性能分析,得出其在一定温度条件下沉积时间对薄膜的光学性质有较大的影响。
Resumo:
光敏CdS粉的制备与性能研究王岚*鲍崇林王给祥(中国科学院长春应用化学研究所,长春130022)关键词半导体,掺杂CdS,烧结,静电复印硫化镉(CdS)是重要的半导体材料,尤其在可见光范围,已经应用到光电导、压电晶体和激光材料上[1].随着近代微电子…
Resumo:
研究了光、热和湿气对CdS/Cu2S电池效率及电池成结、结电容、二极管特性和光谱响应特性的影响。结果表明,对未成结电池光加速成结作用;对成结电池光引起电池性能下降。这种衰降是不可逆过程。
Resumo:
Stable bilayer thin films of indium tin oxide (ITO) on CdS and CdS on ITO were formed for the window material of solar cells by chemical bath and sputtering methods. Scanning electron microscopy and X-ray diffraction studies have shown that both the ITO and CdS films are continuous, homogeneous, with high compactness. Measurement of the CdS film thickness across the 2 x 4 cm(2) reveals the good uniformity of these films. Four-point probe measurements show that the resistivity of a CdS film on an ITO surface is much better than that of the single CdS film The thermal stability of an ITO/CdS bilayer, interfacial reaction and optical transmittance were investigated at different annealing temperatures and environments (air, vacuum and N-2 + H-2). The results showed that the ITO/CdS bilayer film is a good window material for the CuInSe2 and CdTe cells. It is a simple method using a small amount of the cadmium compound.
Resumo:
介绍了用化学水浴法沉积CdS的方法。SEM、XRD以及透射光谱等分析表明,沉积在玻璃片上的CdS膜,均匀、透明、密实,适合制作太阳电池窗口材料。同时简述了CdS膜生长、生成的化学过程和机理。