Papers by Keyword: CdSe

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Authors: Shao Wei Wang, Xia Ona Zhang, Jing Hua Yu
Abstract: A simple route to the production of high-quality CdSe quantum dots (QDs) is presented. The characterization of CdSe QDs was measured by Zetasizer Nano ZS, ultraviolet-visible spectoscopy and fluorospectrophotometer. The CdSe QDs were decorated by 3-Aminobenzeneboronic acid to obtain good fluorescent characteristic. Under the optimal conditions, the decreased normalized absorbance was linear to the concentration of glucose from 1.0×10−7 to 2.9×10−6 mol·L-1 with a detection limit of 5.0´10-8 mol·L-1. The relative standard deviation (RSD) for the determination of 1.0×10-7 mol·L-1 was 1.4 % by 11 replicate determination. In this paper, the fluorescent behavior of glucose with the decorated CdSe QDs was studied, and it is found that the system has a high sensitivity and selectivity for analysis of glucose.
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Authors: Fei Yan Shao, Ming Li, Jian Wen Yang, Yong Pin Liu, Ling Zhi Zhang
Abstract: Different size of colloidal CdSe quantum dot (QD) was synthesized through a simple solvothermal route and their structural, morphological and optical properties were characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), UV-visible absorption spectroscopy and fluorescence spectrometer. XRD and TEM measurement confirmed the formation of CdSe QDs. The red shift of absorption and fluorescence peaks indicated that the size of CdSe QDs increased with prolonging reaction time. The size of QDs varied from 2.2 nm to 3.4 nm by varying reaction time from 1 h to 7 h. The absorption spectra of CdSe/TiO2 electrodes proved that the loading of CdSe QDs on TiO2 can be greatly improved by MPA pretreatment. The effect of size of CdSe QDs on the performance of CdSe QDs sensitized solar cells was investigated. Due to the change of absorption range in the visible region and the conduction band shift for different size of CdSe, the photo-electric power conversion efficiency first increased and then decreased with increasing size of CdSe. The devices fabricated with 3.1 nm diameter CdSe nanoparticles exhibited the highest conversion efficiency of 0.70% under AM 1.5 G irradiation (100 mW cm−2).
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Authors: C.H. Rosmani, S. Abdullah, Mohamad Rusop
Abstract: CdSe thin film was prepared by using spin coating method .The surface morphology of CdSe thin films can be used as the main material in solar cells application, by using sodium selenosulfate as a selenium source and cadmium chloride as cadmium precursor. The solution for each sample had with different molar ratio of cadmium chloride and sodium selenosulfate to know the comparison between the samples. The spin for each samples were constant parameter with 3000 rpm at 30 seconds and dry in ambient temperature. The characterization using atomic force microscopy (AFM) to know the surface morphology of CdSe thin film. The important thing in this paper was to know the surface morphology of CdSe thin films as the comparison with other experiment for solar cells application.
401
Authors: Li Min An, Xuan Lin Chen, Xue Ting Han, Jie Yi, Chun Xia Liu, Wen Yu An, Yu Qiu Qu, Jian Guang Chi, Hong Wei, Kai Yue Qi, Ya Nan Wen, Qiang Wang, Wei Gang Zhou, Hong An Ye, Zhuo Sun
Abstract: CdSe/ZnO core/shell semiconductor nanocrystals which show high luminescence quantum yield have been synthesized through a simple routine without the use of any pyrophoric organometallic precursors. Transmission electron microscope image demonstrates the shape, monodispersity, average size, size distribution and core-shell structure of CdSe/ZnO nanocrystals. We use a combination of X-ray diffraction, UV-Vis absorption spectroscopy and photoluminescence to analyze the core/shell nanocrystals and determine their chemical composition, optical character and internal structure.
207
Authors: Wu Lei Zhou, Tuo Cai, Jian Xiao, Xue Ting Han, Jian Bo Liu, Liang Xu, Jian Guang Chi, Shao Hong Gao, Xi Ping Cai, Li Min An
Abstract: CdSe semiconductor nano crystals (NCs) and Polyaniline (PAni) are mixed uniformly to prepare CdSe NCs/PAni complex. PAni can quench the fluorescent signal of CdSe NCs. The fluorescent intensity of CdSe NCs/PAni complex is related to the size of CdSe NCs and concentration of PAni. Ultraviolet visual (UV-Vis) absorption spectra and fluorescence spectra are employed to analysis the quenching phenomenon. The mechanism of fluorescence quench is dependent on two factors: on one hand, the FÖrster resonance energy transfer conducts from CdSe to PAni; on the other hand, PAni can intercept the electron charge of CdSe and lead to the interruption of radiative recombination.
801
Authors: Juozas Vidmantis Vaitkus
Abstract: A review is given of what kind technological aspects were used for realizing the defect engineering in semiconductor layers or crystals. The possibilities to change the free carrier capture are presented. The effect of Fermi level pinning at the surface levels allow to avoid the influence of barriers on the photoconductivity as well as to increase a role of recombination in the inter-crystalline region. The isovalent doping or the creation of the clusters allows transforming the defect distribution in the crystal bulk. The detector structure using the high electric field can introduce the recombination in at the contacts therefore allow diminishing a role of carrier capture in the bulk of structure. The cluster generation allows to increase the capture rate in the definite volume by a proton irradiation. The experience of different technologies for Si, GaAs, PbS, CdSe are presented.
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Authors: H. Grempel, J. Gutowski, O.S. Ferreira, H. Sitter, D. Hommel, G. Landwehr
183
Authors: Cui Zhi Dong, Li Fang Zhang, Shuang Chen, Ming Xi Zhang, Li Feng, Zhi Min Cui, Qing Jun Zhang
Abstract: CdSe nanocrystalline is an important Ⅱ - Ⅵ clan semiconductor materials, In this paper the hollow structure CdSe nanoparticles was systhesised in CTAB/cyclohexane/isobutanol/water quatemary microemulsion system. The morphology of the final products were characterized by X-ray power diffraction, transmission electron microscopy and EDS. Results of XRD and EDS revealed that nano-crystals were the mixture of CdSe, TEM images shows nanoball, nanotube and bamboo-like nanotube are hollow structure. This paper proves that the hollow structure CdSe can be obtained in the proper conditons.
215
Authors: Heng Kang Qiu, Yue Shen, Lin Jun Wang, Jian Cheng Zhang, Kai Feng Qin
Abstract: For the purpose of investigating the factors induced the non-band-edge excitation optical properties of water-soluble CdSe semiconductor quantum dots (QDs), the initial molar ratio of Cd and Se(or Cd/Se), the temperature of crystal nucleation and growing, the time of the growth etc. are systematically studied in the fabricated process. The properties of the as-prepared nano-particles (NPs) have been characterized by ultraviolet-visible absorption spectra (UV-Vis), photoluminescence (PL) spectroscopy, X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The measured results show that it is possible to exist surface trapping, impurities and other defect energy states in the products with the non-band-edge excitation PL properties, and all the characteristics are involved with the different synthetic routes and prepared techniques.
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