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High‐Yield Fabrication and Electrochemical Characterization of Tetrapodal CdSe, CdTe, and CdSe x Te 1– x Nanocrystals
Author(s) -
Li Y. C.,
Zhong H. Z.,
Li R.,
Zhou Y.,
Yang C. H.,
Li Y. F.
Publication year - 2006
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200500678
Subject(s) - materials science , nanocrystal , nanorod , ternary operation , wurtzite crystal structure , photoluminescence , cadmium telluride photovoltaics , high resolution transmission electron microscopy , nanoparticle , nanotechnology , transmission electron microscopy , chemical engineering , crystallography , zinc , optoelectronics , chemistry , engineering , metallurgy , computer science , programming language
The high‐yield fabrication of tetrapodal CdSe, CdTe, and CdSe x Te 1– 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 CdSe x Te 1– 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 CdSe x Te 1– 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 CdSe x Te 1– x alloyed nanocrystals. The band‐edge positions of the nanocrystals of CdSe, CdSe x Te 1– x , and CdTe are systematically studied by cyclic voltammetry.