Synthesis and characterization of surface-modified colloidal CdTe Quantum Dots
- Inst. of Nuclear Sciences, Belgrade (Yugoslavia)
- National Renewable Energy Lab., Golden, CO (United States)
The controlled synthesis of quantized colloidal CdTe nanocrystals (in aqueous solutions) with narrow size distributions and stabilized against rapid oxidation was achieved by capping the quantum dot particles with 3-mercapto-1,2-propanediol. Nanocrystals (i.e., quantum dots) with mean diameters of 20, 25, 35, and 40 A were produced. Optical absorption spectra showed strong excitonic peaks at the smallest size; the absorption coefficient was shown to follow an inverse cube dependence on particle diameter, while the extinction coefficient per particle remained constant. The quantum yield for photoluminescence increased with decreasing particle size and reached 20% at 20 A. The valence band edges of the CdTe quantum dots were determined by pulse radiolysis experiments (hole injection from oxidizing radicals); the bandgaps were estimated from pulse radiolysis data (redox potentials of hole and electron injecting radicals) and from the optical spectra. The dependence of the CdTe bandgap on quantum dot size was found to be much weaker than predicted by the effective mass approximation; this result is consistent with recently published theoretical calculations by several groups. 36 refs., 5 figs., 1 tab.
- OSTI ID:
- 5424486
- Journal Information:
- Journal of Physical Chemistry; (United States), Vol. 97:46; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Quantum Size level Structure of Colloidal CdTe Quantum Dot Nanocrystal: A Multi-band Approach
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CADMIUM TELLURIDES
ABSORPTION SPECTRA
PHOTOLUMINESCENCE
SYNTHESIS
X-RAY DIFFRACTION
ALCOHOLS
COLLOIDS
COMPILED DATA
CRYSTALS
RADIOLYSIS
CADMIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
COHERENT SCATTERING
DATA
DECOMPOSITION
DIFFRACTION
DISPERSIONS
HYDROXY COMPOUNDS
INFORMATION
LUMINESCENCE
NUMERICAL DATA
ORGANIC COMPOUNDS
RADIATION EFFECTS
SCATTERING
SPECTRA
TELLURIDES
TELLURIUM COMPOUNDS
400201* - Chemical & Physicochemical Properties
400500 - Photochemistry
400102 - Chemical & Spectral Procedures