Document Detail


Morphology control of cadmium selenide nanocrystals: insights into the roles of di-n-octylphosphine oxide (DOPO) and ucid (DOPA).
MedLine Citation:
PMID:  22369500     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Di-n-octylphosphine oxide (DOPO) and di-n-octylphosphinic acid (DOPA), as two of impurities found in commercial tri-n-octylphosphine oxide (TOPO), generate significant differences in the outcomes of CdSe-nanocrystal (NC) syntheses. Using n-tetradecylphosphonic acid (TDPA) as the primary acid additive, quantum dots (QDs) are grown with DOPO added, whereas quantum rods (QRs) are grown in the presence of DOPA. While using oleic acid (OA) as the primary acid additive, QDs are generated and the QDs produced with DOPA exhibit larger sizes and size distributions than those produced with DOPO. (31)P NMR analyses of the reaction mixtures reveal that the majority of the DOPO has been converted into DOPA and di-n-octylphosphine (DOP) with DOP being removed via evacuation over the course of Cd-precursor preparation. The origin of the puzzling differences in the shape control of CdSe NCs in the presence of DOPO and DOPA is elucidated to be the small quantity of DOPO present, which liberates DOP during NC synthesis. In the presence of DOP, regardless of DOPA, the precursor-conversion kinetics and thus the nucleation kinetics are dramatically accelerated, generating a large number of nuclei by consuming a significant amount of CdSe nutrients, favoring QD growth. Similarly, QD growth is favored by the fast nucleation kinetics in the presence of OA, and the broader size distributions of QDs with DOPA are due to a second nucleation event initiated by the more stable Cd-di-n-octylphosphinate component. In contrast, a slow nucleation event results in the growth of QRs in the case of using DOPA and TDPA, where no DOPO or DOP is present. The results, thus, demonstrate the important role of precursor-conversion kinetics in the control of NC morphologies.
Authors:
Fudong Wang; William E Buhro
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-03-06
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  134     ISSN:  1520-5126     ISO Abbreviation:  J. Am. Chem. Soc.     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-03-21     Completed Date:  2012-07-25     Revised Date:  2013-12-18    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5369-80     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Cadmium Compounds / chemical synthesis,  chemistry*
Nanoparticles / chemistry*
Organophosphorus Compounds / chemical synthesis,  chemistry*
Particle Size
Selenium Compounds / chemical synthesis,  chemistry*
Surface Properties
Grant Support
ID/Acronym/Agency:
P41 RR000954/RR/NCRR NIH HHS; P41 RR000954-32/RR/NCRR NIH HHS; P41RR0954/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Cadmium Compounds; 0/Organophosphorus Compounds; 0/Selenium Compounds; 0/di-n-octylphosphine oxide; 0/di-n-octylphosphinic acid; A7F646JC5C/cadmium selenide
Comments/Corrections

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