Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (01): 232-238.doi: 10.3866/PKU.WHXB201111151

• PHYSICAL CHEMISTRY OF MATERIALS • Previous Articles     Next Articles

Effects of CdSe Layer Number on the Optical Properties and Microstructures of CdTe/CdSe (II) Core/Shell Quantum Dots

PENG Jing, FANG Xiao-Ming, CHEN Zhi-Hong, ZHANG Zheng-Guo   

  1. Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, P. R. China
  • Received:2011-07-14 Revised:2011-11-01 Published:2011-12-29
  • Contact: FANG Xiao-Ming
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20573038, 60976053).

Abstract: CdTe/CdSe core/shell quantum dots (QDs) with different numbers of CdSe layers were synthesized in aqueous media by sequentially adding freshly-prepared solutions of NaHSe and CdCl2 to a solution of CdTe QDs several times. The optical properties and microstructures of the resulting QDs were investigated. Compared with those of CdTe QDs, the optical absorption and fluorescence emission peaks of CdTe/CdSe core/shell QDs with a single CdSe layer shifted to longer wavelength. As the number of CdSe layers was increased, the optical absorption spectra of the CdTe/CdSe core/shell QDs covered a wider range and extended to longer wavelengths, the intensity of fluorescence emission decreased gradually, and the fluorescence lifetime increased significantly, consistent with the behavior of type II core/ shell QDs. Compared with those of CdTe/CdSe QDs with a single CdSe layer, the diffraction peaks of the CdTe/CdSe QDs with three CdSe layers shifted from the standard positions of CdTe diffraction peaks to those of CdSe. The CdTe/CdSe type II core/shell QDs show promise for application in solar cells because of their broad absorption spectra that extend to longer wavelengths.

Key words: Quantum dot, Type II core/shell heterostructure, CdTe/CdSe, Aqueous synthesis


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