| The Importance of Nanocrystal Precursor Conversion Kinetics: Mechanism of the Reaction Between Cadmium Carboxylate and Cadmium Bis-diphenyldithiophosphinate. | |
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MedLine Citation:
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PMID: 23043371 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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We describe the synthesis of cadmium bis-(diphenyldithiophosphinate) (Cd(S(2)PPh(2))(2)) from secondary phosphine sulfides and its conversion to cadmium sulfide nanocrystals. Heating Cd(S(2)PPh(2))(2) and cadmium tetradecanoate (≥4 equiv.) to 240 ˚C results in complete conversion of Cd(S(2)PPh(2))(2) to cadmium sulfide nanocrystals with tetradecanoate surface termination. The nanocrystals have a narrow size distribution (d = 3.8-4.1 nm, σ < 10%) that is evident from the linewidth of the lowest energy absorption feature (λ = 412 - 422 nm, fwhm = 0.17 eV) and display bright photoluminescence (PLQY(band edge + trap) = 36%). Interestingly, the final diameter is insensitive to the reaction conditions, including the total concentration of precursors and initial cadmium to sulfur ratio. Monitoring the reaction with (31)P NMR, UV-Visible, and infrared absorption spectroscopies shows that the production of cadmium diphenylphosphinate (Cd(O(2)PPh(2))(2)) and tetradecanoic anhydride co-products is coupled with the formation of cadmium sulfide. From these measurements we propose a balanced chemical equation for the conversion reaction and use it to optimize a synthesis that affords CdS nanocrystals in quantitative yield. In light of these results we discuss the importance of well-defined precursor reactivity to reproducible conversion kinetics and the synthesis of nanocrystals with unambiguous chemical composition. |
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Authors:
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Mark P Hendricks; Brandi M Cossairt; Jonathan S Owen |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-10-8 |
Journal Detail:
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Title: ACS nano Volume: - ISSN: 1936-086X ISO Abbreviation: ACS Nano Publication Date: 2012 Oct |
Date Detail:
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Created Date: 2012-10-9 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101313589 Medline TA: ACS Nano Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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