High-Yield Fabrication and Electrochemical Characterization of Tetrapodal CdSe, CdTe, and CdSexTe1–x Nanocrystals

Authors

  • Y. C. Li,

    1. CAS Key Laboratory of Organic Solids, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
    2. Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • H. Z. Zhong,

    1. CAS Key Laboratory of Organic Solids, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
    2. Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • R. Li,

    1. CAS Key Laboratory of Organic Solids, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
    2. Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • Y. Zhou,

    1. CAS Key Laboratory of Organic Solids, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
    2. Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
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  • C. H. Yang,

    1. CAS Key Laboratory of Organic Solids, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
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  • Y. F. Li

    1. CAS Key Laboratory of Organic Solids, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China
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  • This work was supported by the State Key Basic Research Project (No. 2001CB610507, 2002CB613404), The Ministry of Science and Technology of China, and the NSFC (No. 20421101). Supporting Information is available online from Wiley InterScience or from the author.

Abstract

The high-yield fabrication of tetrapodal CdSe, CdTe, and CdSexTe1–x nanocrystals is systematically studied. CdSe nanocrystals are prepared by first controlling the synthesis of high-quality wurtzite CdSe and zinc blende CdSe nanocrystals at a relatively high temperature (260 °C) by selecting different ligands. Then, based on the phase control of the CdSe nanocrystals, two nanoparticle-tailoring routes (i.e., a seed-epitaxial route and ligand-dependent multi-injecting route) are used, and a high yield of CdSe tetrapods is obtained. CdTe nanocrystals are prepared by adjusting the ligand composition and the ratio of Cd to Te; CdTe tetrapods are synthesized in high yield using a mixed ligand that does not contain alkylphosphonic acids. Moreover, the nanoscale Te powder (Te nanowires/nanorods), which is highly soluble in the ligand solvent, is first used as a Te source to synthesize CdTe nanocrystals, which remarkably enhanced the output of the CdTe nanocrystals in one reaction. Furthermore, composition-tunable ternary CdSexTe1–x alloyed tetrapods are synthesized on a large scale, for the first time, by thermolyzing the mixture of the organometallic Cd precursor and the mixed (Se + Te) source in a mixed-ligand solution. The CdSe, CdTe, and CdSexTe1–x nanocrystals are characterized by transmission electron microscopy (TEM), high-resolution TEM, selected-area electron diffraction, X-ray diffraction, and UV-vis and photoluminescence (PL) spectroscopy. Interesting nonlinear, composition-dependent absorption and PL spectra are observed for the ternary CdSexTe1–x alloyed nanocrystals. The band-edge positions of the nanocrystals of CdSe, CdSexTe1–x, and CdTe are systematically studied by cyclic voltammetry.

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