巯基包覆CdSe和CdSe/CdS核壳纳米晶的水相合成与表征(英文)  

Synthesis and Characterization of Thiol-Capped CdSe and CdSe/CdS Core/Shell Nanocrystals in Aqueous Solution

作　　者：安利民[1] 孔祥贵[2] 刘益春[3] 单桂晔[2] 吕强[2] 王新[2] 曾庆辉[2] 朝克夫[2] 冯力蕴[2] 张友林[2] 

机构地区：[1]黑龙江大学物理科学与技术学院,哈尔滨150080 [2]中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,长春130021 [3]东北师范大学物理学院,长春130024

出　　处：《纳米技术与精密工程》2004年第3期175-181,共7页Nanotechnology and Precision Engineering

基　　金：Supportedby"973"ResearchPlan(No.G1 9990 5450 4 )and"863"ResearchPlan(No .2 0 0 2AA30 2 2 0 3) .

摘　　要：利用水相合成的方法制备了巯基包覆的具有较高荧光量子产率的CdSe和CdSe/CdS纳米晶 .水相合成方法的优点是原料低廉、安全可靠和重复性高 ,缺点是纳米晶的尺寸分布较宽 ,发光效率不是很高 .采用X—射线粉末衍射、吸收和荧光等光谱手段对纳米晶的平均尺度、粒径分布、晶体结构及发光特性进行了表征。在 77K到 3 0 0K的温度范围内 ,随着温度降低 ,CdSe纳米晶的发光峰逐渐蓝移 ,而CdSe/Cds纳米晶发光峰位基本不随温度变化而变化 .此外 ,在 3 2 5nm激光辐照下 ,CdSe/CdS纳米晶的荧光寿命比CdSe纳米晶延长了 6倍左右 ,稳定性大幅度提高 .以上结果表明 ,核壳结构的CdSe/CdS纳米晶具有较高的发光效率和良好的稳定性 ,具有广阔的应用前景 .Thiol-capped CdSe/CdS core/shell nanocrystals(NCs)which show high luminescence quantum yield are synthesized in aqueous solution.The synthesis in an aqueous medium without any poisonous materials is attached importance to.The simplicity and high reproducibility are notable among the advantages of the aqueous synthesis.A combination of X-ray diffraction(XRD),UV-Vis absorption spectroscopy and photoluminescence(PL) spectroscopy are employed to analyze the NCs and determine their crystal structures,optical characters and stabilities.Furthermore,PL properties are studied in a temperature range between 77 K and 300 K,which haven't been reported before. The PL peak position of CdSe NCs shifts toward shorter wavelengths and the band becomes sharper with decreasing temperature.At the same condition, the PL peak position of CdSe/CdS NCs keeps unconverted nearly with the variation of temperature. The results indicate that the CdS shell can improve the temperature-dependent stability of CdSe NCs effectively.Photostabilities of CdSe and CdSe/CdS NCs are compared under 325 nm laser irradiation.It takes 78 s that the PL intensity decrease to the half for CdSe NCs,but 442 s for CdSe/CdS core/shell NCs.The fluorescence lifetime increases about six times due to overcoating.The CdSe/CdS NCs will be useful in the practical application for their advantages in synthesis procedure and optical properties.

关 键 词：合成与表征 纳米晶 发光峰 水相 核壳 荧光寿命 蓝移 发光效率 发光特性 激光辐照 

分 类 号：TB383[一般工业技术—材料科学与工程]