Linear-Polarization Optical Property of CdSe Quantum Rods

The linear-polarization optical property of CdSe quantum rods is studied in the framework of effective-mass envelope function theory.The effects of shape and magnetic field on the linear polarization factors are investigated.It is found that CdSe quantum spheres have negative polarization factors (xy-polarized emission)and quantum long rods with small radius have positive linear polarization factors (z-polarized emission).The z-direction is the direction of the c axis.Quantum long rods with large radius have negative linear polarization factors,due to the hexagonal crystal symmetry and the crystal field splitting energy.The linear polarization factors decrease and may change from a positive value to a negative value;i.e.,the z-polarized emissions decrease relative to xy-polarized emissions as the magnetic field applied along the z direction increases.

Y沸石中组装CdSe纳米团簇的实验研究

采用离子交换方法，在Y型沸石分子筛中首次组装了质量比分别为5%和15%的CdSe纳米团簇；样品漫反射光谱和透射电镜形貌相的实验结果证实，该制备过程是成功可行的，并得到了分布均匀、尺寸比较单一的团簇材料。采用正电子湮没寿命谱对上述两种样品、Y型沸石原粉和纯的CdSe粉末样品进行测量，得到了有关团簇生长过程及其微结构的有用信息。

CdSe纳米团簇的透射电镜研究

在沸石分子筛中组装CdSe而形成半导体纳米团簇材料，并将组装CdSe后的沸石微粉制成完整的透射电镜薄膜，结合能谱测试，在透射电镜下观察所制得的材料的微观结构和形貌。结果表明在沸石中形成了尺寸单一、分布均匀的团簇材料。

[（CdSe）m（ZnSe）n]p-ZnSe多量子阱中的多声子散射

于2010-11-23批量导入

Characterization of CdSe and CdSe/CdS core/shell nanoclusters synthesized in aqueous solution

CdSe nanoclusters overcoated with CdS shell were prepared with macapoacetic acid as stabilizer. The optical properties of CdSe nanoclusters and the influence of CdS shell on the electronic structures of CdSe cores were studied by optical absorption, photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies. Based on PL and PLE results and the theoretical calculation on fine structure of bandedge exciton, a model of formation of excimer within the small clusters was proposed to explain the large Stokes shift of luminescence from absorption edge observed in PL results. (C) 2000 Elsevier Science B.V. All rights reserved.

Nd3+-doped LaF3 nanoparticles with a larger emission cross-section

A series of Nd3+-doped LaF3 nanoparticles with Nd3+ concentrations from 0.5 to 10 mol% were synthesized. The fluorescence intensity and lifetime of the nanoparticles at various Nd3+ doping concentration were investigated. The nanoparticles displayed strongest fluorescence intensity at 3 mol% Nd3+ concentration. Eighty-eight percentage quantum efficiency was obtained when the Nd3+ concentration was 0.5 mol%. Optical properties of nanoparticles were studied according to Judd-Ofelt theory. A larger emission cross-section, sigma(em), for F-4(3/2) -> I-4(11/2) transition of the Nd3+ ion was obtained as 3.21 x 10(-20) cm(2), which was two times of the currently reported value. The larger emission cross-section and strong fluorescence intensity demonstrate that these nanoparticles are promising materials for laser applications. (C) 2010 Published by Elsevier B. V.