The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ...The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ZnS e to Cd（NO3）2 on the morphology and structure of the final product was investigated. And the performances of ZnS e/Cd Se core-shell structure nanocomposites were characterized by the means of X-ray diffraction（XRD） analyses, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and photoluminescence（PL） spectroscopy. The results indicate that the core-shell structure product can be prepared, when the mole ratio of Zn Se to Cd（NO3）2 is larger than 1：1; and the product will be ball solid structure, when the mole ratio of Zn Se to Cd（NO3）2 is equal to 1：1. The photo luminescence results show that Zn Se/Cd Se core-shell structures have high photo luminescence emission properties, and the product with mole ratio of Zn Se to Cd（NO3）2 being 1：0.5 has the best luminescence properties.展开更多
We report a facile aqueous phase synthesis for prepar-ing water-soluble inverted core/shell ZnSe/CdSe semiconductor nanocrystals. The samples were characterized by X-ray diffraction (XRD),transmission electron microsc...We report a facile aqueous phase synthesis for prepar-ing water-soluble inverted core/shell ZnSe/CdSe semiconductor nanocrystals. The samples were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and their optical properties were investigated by using UV-vis-NIR spectropho-tometer and fluorescence spectrophotometer. The results indicate that the synthesized ZnSe/CdSe nanocrystals are inverted core/shell structure with diameter of about 5 nm. Furthermore,their absorption band-edge is red-shifted with the growth of CdSe shell; correspondingly,their emission wavelength can be tuned from 460 nm to 604 nm.展开更多
High-quality Zn-doped CdSe core-shell nanocrystals were successfully prepared by incorporating a stoichiometric amount of Zn precursor into the CdSe reaction system, in which the Se precursor was excess and an Se-rich...High-quality Zn-doped CdSe core-shell nanocrystals were successfully prepared by incorporating a stoichiometric amount of Zn precursor into the CdSe reaction system, in which the Se precursor was excess and an Se-rich surface was formed. By injecting different amounts of Zn precursor, the core-shell nanocrystals demonstrated by the emission spectra were formed. The obtained Zn-doped CdSe nanocrystals exhibit a photoluminescence efficiency from 30% to 85%, which is comparable to those for the reported CdSe/ZnS, CdSe/CdS in the literature. In particular, a shell ZnSe layer with different thicknesses of ZnSe can be formed in this experiment by only changing the amount of Zn precursor added, which is simple and effective.展开更多
The electronic structures of (CdSe)n/(ZnSe)m strained-lager soperfattice (SLS) were investigated by the recursion method in the tight-bindiop opproximation. The total,local, and partial density of states were calculat...The electronic structures of (CdSe)n/(ZnSe)m strained-lager soperfattice (SLS) were investigated by the recursion method in the tight-bindiop opproximation. The total,local, and partial density of states were calculated for n=1, m=5.The total density of states (TDOS) for bulk CdSe, ZnSe and n=1, 3, m=1, 3, 5, for SLS were investigated.Fermi energy, the band gap, the valence of an atom, and the ionization potential and the electron affinity were discassed.展开更多
基金Project(13JJ1005)supported by the Natural Science Foundation for Distinguished Young Scholars of Hunan Province,China
文摘The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ZnS e to Cd（NO3）2 on the morphology and structure of the final product was investigated. And the performances of ZnS e/Cd Se core-shell structure nanocomposites were characterized by the means of X-ray diffraction（XRD） analyses, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and photoluminescence（PL） spectroscopy. The results indicate that the core-shell structure product can be prepared, when the mole ratio of Zn Se to Cd（NO3）2 is larger than 1：1; and the product will be ball solid structure, when the mole ratio of Zn Se to Cd（NO3）2 is equal to 1：1. The photo luminescence results show that Zn Se/Cd Se core-shell structures have high photo luminescence emission properties, and the product with mole ratio of Zn Se to Cd（NO3）2 being 1：0.5 has the best luminescence properties.
基金Supported by the National Natural Science Foundation of China (10874134)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060486031)
文摘We report a facile aqueous phase synthesis for prepar-ing water-soluble inverted core/shell ZnSe/CdSe semiconductor nanocrystals. The samples were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and their optical properties were investigated by using UV-vis-NIR spectropho-tometer and fluorescence spectrophotometer. The results indicate that the synthesized ZnSe/CdSe nanocrystals are inverted core/shell structure with diameter of about 5 nm. Furthermore,their absorption band-edge is red-shifted with the growth of CdSe shell; correspondingly,their emission wavelength can be tuned from 460 nm to 604 nm.
文摘High-quality Zn-doped CdSe core-shell nanocrystals were successfully prepared by incorporating a stoichiometric amount of Zn precursor into the CdSe reaction system, in which the Se precursor was excess and an Se-rich surface was formed. By injecting different amounts of Zn precursor, the core-shell nanocrystals demonstrated by the emission spectra were formed. The obtained Zn-doped CdSe nanocrystals exhibit a photoluminescence efficiency from 30% to 85%, which is comparable to those for the reported CdSe/ZnS, CdSe/CdS in the literature. In particular, a shell ZnSe layer with different thicknesses of ZnSe can be formed in this experiment by only changing the amount of Zn precursor added, which is simple and effective.
文摘The electronic structures of (CdSe)n/(ZnSe)m strained-lager soperfattice (SLS) were investigated by the recursion method in the tight-bindiop opproximation. The total,local, and partial density of states were calculated for n=1, m=5.The total density of states (TDOS) for bulk CdSe, ZnSe and n=1, 3, m=1, 3, 5, for SLS were investigated.Fermi energy, the band gap, the valence of an atom, and the ionization potential and the electron affinity were discassed.
