Document Detail

Structure and ultrafast dynamics of white-light-emitting CdSe nanocrystals.
MedLine Citation:
PMID:  19341271     Owner:  NLM     Status:  MEDLINE    
White-light emission from ultrasmall CdSe nanocrystals offers an alternative approach to the realization of solid-state lighting as an appealing technology for consumers. Unfortunately, their extremely small size limits the feasibility of traditional methods for nanocrystal characterization. This paper reports the first images of their structure, which were obtained using aberration-corrected atomic number contrast scanning transmission electron microscopy (Z-STEM). With subangstrom resolution, Z-STEM is one of the few available methods that can be used to directly image the nanocrystal's structure. The initial images suggest that they are crystalline and approximately four lattice planes in diameter. In addition to the structure, for the first time, the exciton dynamics were measured at different wavelengths of the white-light spectrum using ultrafast fluorescence upconversion spectroscopy. The data suggest that a myriad of trap states are responsible for the broad-spectrum emission. It is hoped that the information presented here will provide a foundation for the future development and improvement of white-light-emitting nanocrystals.
Michael J Bowers; James R McBride; Maria D Garrett; Jessica A Sammons; Albert D Dukes; Michael A Schreuder; Tony L Watt; Andrew R Lupini; Stephen J Pennycook; Sandra J Rosenthal
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  131     ISSN:  1520-5126     ISO Abbreviation:  J. Am. Chem. Soc.     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-04-22     Completed Date:  2009-06-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5730-1     Citation Subset:  IM    
Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA.
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MeSH Terms
Cadmium / chemistry*
Microscopy, Electron, Scanning Transmission / methods*
Nanoparticles / chemistry*,  ultrastructure*
Particle Size
Selenium / chemistry*
Spectrometry, Fluorescence / methods
Time Factors
Reg. No./Substance:
7440-43-9/Cadmium; 7782-49-2/Selenium

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

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