高等学校化学学报 ›› 2009, Vol. 30 ›› Issue (9): 1789.

• 研究论文 • 上一篇    下一篇

CdTe/CdS量子点的Ⅰ-Ⅱ型结构转变与荧光性质

安利民1,2, 曾庆辉3, 赵家龙3, 宋维斯1, 苏文辉1   

  1. 1. 哈尔滨工业大学物理系, 凝聚态科学与技术研究中心, 哈尔滨 150001;
    2. 黑龙江大学物理科学与技术学院, 哈尔滨 150080;
    3. 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 130033
  • 收稿日期:2008-12-08 出版日期:2009-09-10 发布日期:2009-09-10
  • 通讯作者: 苏文辉, 男, 教授, 博士生导师,主要从事凝聚态物质的物理和化学性质研究. E-mail: suwenhui@hit.edu.cn; 安利民, 男, 博士, 讲师, 主要从事无机纳米材料的合成与光学性质研究. E-mail: anlimin@hlju.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 10674034, 60478015, 60771051, 60601014, 20603035)、国家“八六三”计划(批准号: 2006AA03Z335)和黑龙江省教育厅项目(批准号: 11533047)资助.

Structure Transition and Luminescence Properties of CdTe/CdS Quantum Dots

AN Li-Min1,2*, ZENG Qing-Hui3, ZHAO Jia-Long3, SONG Wei-Si1, SU Wen-Hui1*   

  1. 1. Center for the Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001, China;
    2. Physics Department of Science and Technology, Heilongjiang University, Harbin 150080, China;
    3. Key Laboratory of Excited State Processes, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
  • Received:2008-12-08 Online:2009-09-10 Published:2009-09-10
  • Contact: SU Wen-Hui. E-mail: suwenhui@hit.edu.cn; AN Li-Min. E-mail: anlimin@hlju.edu.cn
  • Supported by:

    国家自然科学基金(批准号: 10674034, 60478015, 60771051, 60601014, 20603035)、国家“八六三”计划(批准号: 2006AA03Z335)和黑龙江省教育厅项目(批准号: 11533047)资助.

摘要:

制备了壳层厚度可以精确控制的CdTe/CdS核壳量子点, 利用紫外-可见吸收光谱、光致发光光谱、透射电镜和时间分辨光谱等技术, 分析了CdS壳层厚度对CdTe量子点的荧光量子产率和光谱结构的影响规律. 发现了不同于CdSe/CdS, CdSe/ZnS, CdTe/ZnS等核壳量子点的荧光峰展宽、大幅度红移以及荧光寿命大幅度增加现象. 根据能带的位置关系, 随着CdS厚度的增加, CdTe从Ⅰ型结构逐渐过渡到Ⅱ型核壳结构. 对于Ⅱ型CdTe/CdS核壳量子点, 不仅存在CdTe核区导带电子与价带空穴间的直接复合, 还存在CdS壳层导带电子与CdTe核价带空穴界面处的间接复合, 发光机制的变化导致荧光峰的展宽、明显红移和荧光寿命的增加. 当壳层过厚时, 壳层表面新引入的缺陷会阻碍荧光寿命和量子产率的进一步提高.

关键词: 碲化镉; 碲化镉/硫化镉; 量子点; 荧光寿命

Abstract:

Water-soluble CdTe/CdS core-shell quantum dots(QDs) with the different shell thickness capped with 3-mercaptopropionic acid were synthesized following the synthetic method of successive ion layer adsorption and reaction. UV-Vis absorption spectroscopy, photoluminescence(PL) spectroscopy, transmission electron microscopy(TEM) and time-resolved luminescence were employed to analyze optical characters of QDs. The CdTe/CdS QDs exhibited a significant red shift of emission peak, FWHM increasing and PL lifetime lengthening when the shell layer grew. The experiments revealed that the CdTe/CdS QDs evolve from type-Ⅰ to type-Ⅱ core-shell structure with the increase of the shell thickness. The lack of PL lifetime lengthening and quantum yield increasing was ascribed to the surface influence of the shell.

Key words: CdTe; CdTe/CdS; Quantum dot; Photoluminescence lifetime

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