Document Detail


Tuning of the fluorescence wavelength of CdTe quantum dots with 2 nm resolution by size-selective photoetching.
MedLine Citation:
PMID:  19423928     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Photoetching of CdTe nanocrystals was applied to thiol-capped CdTe quantum dots (QDs) to control their fluorescence wavelength. CdTe QDs with a high quantum yield (49%) were synthesized in aqueous solution, and they were successfully photoetched in strong alkaline (pH = 13.5) conditions. When monochromatic light was used, size-selective photoetching could be conducted; the photoetching proceeded until the band gap energy of the CdTe QDs increased to the energy corresponding to the wavelength of the irradiating light. As a result, a good linear relationship was obtained between the wavelength of the irradiating light and that of the fluorescence peak. The resulting CdTe QDs exhibited a fluorescence peak with an FWHM value as small as 23.5 nm, indicating preparation of highly monodispersed nanocrystals. The high quantum yield (ca. 45%) was maintained after the photoetching. Very fine tuning of the fluorescence wavelength with 2 nm resolution was achieved by changing the wavelength of the irradiating light by 2 nm. Theoretical calculation of the quantum size effects (effective mass approximation) predicts that a difference in the band gap fluorescence wavelength of 2 nm corresponds to a change in particle diameter of ca. 0.02 nm.
Authors:
T Uematsu; H Kitajima; T Kohma; T Torimoto; Y Tachibana; S Kuwabata
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-05-05
Journal Detail:
Title:  Nanotechnology     Volume:  20     ISSN:  1361-6528     ISO Abbreviation:  Nanotechnology     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-05-08     Completed Date:  2009-07-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101241272     Medline TA:  Nanotechnology     Country:  England    
Other Details:
Languages:  eng     Pagination:  215302     Citation Subset:  IM    
Affiliation:
Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan.
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MeSH Terms
Descriptor/Qualifier:
Cadmium Compounds / chemistry*
Crystallization / methods*
Macromolecular Substances / chemistry
Materials Testing
Molecular Conformation
Nanostructures / chemistry*,  ultrastructure
Nanotechnology / methods*
Particle Size
Photochemistry / methods*
Quantum Dots*
Spectrometry, Fluorescence / methods*
Surface Properties
Tellurium / chemistry*
Chemical
Reg. No./Substance:
0/Cadmium Compounds; 0/Macromolecular Substances; 1306-25-8/cadmium telluride; 13494-80-9/Tellurium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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