Three families of colloidal CdSe magic-sized nanocrystals (MSNs) exhibiting bright bandgap photoluminescence (PL) with narrow full width at half-maximum (fwhm) on the order of ca. 10 nm were synthesized in pure form. This noninjection one-pot synthetic approach uses cadmium acetate dihydrate (Cd(OAc)2·2H2O) and elemental selenium as Cd and Se source compounds, respectively, while a fatty acid as surface ligands and 1-octadecene (ODE) as the reaction medium. All of these chemicals were loaded at room temperature in a reaction flask, with low acid-to-Cd and high Cd-to-Se feed molar ratios; the growth of the CdSe MSNs was carried out at 120 −240 °C. This synthetic approach allows long growth/annealing periods at high temperature and thus results in high-quality CdSe MSNs exhibiting strong bandgap PL; furthermore, this ready approach features high synthetic reproducibility and large-scale production. The reason for the low acid-to-Cd feed molar ratio is argued to be related to the low activity of the Cd precursor in the form of Cd(OAc) x (OOC−(CH2) n −CH3)2−x , which releases Cd slowly. The reason for the high Cd-to-Se feed molar ratio is also addressed to help prevent the dissociation of the formed CdSe MSNs. Furthermore, short ligand and low temperature favors the formation of small MSNs, while long ligand and high temperature favors large MSNs. Regarding our synthetic approach, these MSN families can coexist together with one regular nanocrystal ensemble which is larger in size; in such a case, they develop independently from different nuclei; the small MSN families can dissociate into monomers to feed the formation of other MSN families and/or the regular nanocrystal ensemble. The three MSN families exhibit sharp bandgap absorption at 395, 463, and 513 nm, within the size range of 1.7−2.2 nm by diffusion ordered NMR spectroscopy (DOSY).

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/jp809990aAccess and use of this website and the material on it are subject to the Terms and Conditions set forth at Single-sized CdSe nanocrystals with bandgap photoemission via a noninjected one-pot approach Yu, Kui; Ouyang, Jianying; Zaman, Md. Badruz; Johnston, Dennis; Yan, Fu Jian; Li, Grace; Ratcliffe, Christopher I.; Leek, Donald M.; Wu, Xiaohua; Stupak, Jacek; Jakubek, Zygmunt; Whitfield, Dennis http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/droits L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=08c76c5f-73da-4536-8c4e-8c0a4441510d http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=08c76c5f-73da-4536-8c4e-8c0a4441510d The manuscript addresses the synthesis and characterization of one colloidal CdSe single-sized nanocrystal ensemble exhibiting bandgap absorption and emission peaking at 463 and 465 nm, respectively, with full width at half-maximum of ca. 8 nm. This ensemble is called Family 463; also, these single-sized quantum dots (QDs) are termed as magic-sized quantum dots (MSQDs). A magic-sized quantum dot (MSQD) ensemble is similar to a regular quantum dot (RQD) ensemble but consisting of single-sized nanocrystals; meanwhile, MSQDs do not grow in size any more with longer reaction periods or higher temperature, after their well development during synthesis. The CdSe MSQDs were synthesized via a noninjection one-pot approach with long reaction periods at elevated temperature, with cadmium acetate dihydrate (Cd(OAc) 2 · 2H 2 O) and elemental selenium as Cd and Se sources, respectively, one long-chain fatty acid as ligands, and 1-octadecene (ODE) as a reaction medium. Different carboxylic acids with the carbon-chain length ranging from C2 to C24, the number of which refers to the total number of carbons, were inve...