White-Light Emission from Magic-Sized Cadmium Selenide Nanocrystals

Bowers, Michael J.; McBride, James R.; Rosenthal, Sandra J.

doi:10.1021/ja055470d

Cited by 641 publications

(625 citation statements)

References 18 publications

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“…Note that the absorption and emission maxima of the MSQD ensemble are independent of the growth periods during the reaction (as shown in the Supporting Information, Figure S1), implying stability in size with a constant bandgap; the growth pattern shows the typical characteristics of MSQDs. [13][14][15][16][17][18][19][20][21][22][23] Thus, the value of the energy difference of the present absorption doublet of the CdTeSe MSQDs is larger than those of the CdSe MSQDs and smaller than that of the CdTe MSQDs. Such a difference in the value of the energy difference of the absorption doublet suggests that the present MSQDs represent a ternary system.…”

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confidence: 92%

“…4 In fact, they were discovered as molecular cluster-like precursors leading to the formation of larger aggregates with various morphologies such as wire-like. [13][14][15][16] It is noteworthy that, for those II-VI MSQDs reported, [17][18][19][20][21][22] they exhibited no bandgap but trap emission; and very often, several families of different sizes coexisted in one synthetic batch. 19,20 It was not until recently that PbSe MSQDs were claimed to have bandgap emission, but unfortunately with broad bandwidth, 23 which might result from the nature of the broad homogeneous fluorescence line width.…”

Section: Introductionmentioning

confidence: 99%

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Homogeneously-Alloyed CdTeSe Single-Sized Nanocrystals with Bandgap Photoluminescence

et al. 2009

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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. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=16120cb5-f193-4c66-811a-45fa8876ee76 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=16120cb5-f193-4c66-811a-45fa8876ee76 Homogeneously alloyed ternary CdTeSe magic-sized nanocrystals (MSNs) with bandgap emission were synthesized in 1-octadecene (ODE) via a noninjection one-pot approach featuring synthetic reproducibility and large-scale capability. The noninjection approach used cadmium acetate dihydrate (Cd(OAc) 2 · 2H 2 O), elemental selenium, and elemental tellurium as Cd, Se, and Te sources, respectively. The growth of the CdTeSe nanocrystals was carried out at temperatures from 120 to 200°C for several hours in a reaction flask containing the reactants together with a long-chain fatty acid as capping ligands and ODE as the reaction medium. During synthesis, the CdTeSe nanocrystals exhibited persistent bandgap and did not grow in size anymore after their formation, either with longer growth periods or higher reaction temperature. Also, they exhibit an absorption doublet with 288 meV energy difference between the two peaks; the first excitonic transition peak is at 520 nm and bandgap photoemission peak at 524 nm with full width at half-maximum (fwhm) of ca. 20 nm. Both the growth pattern and the optical properties suggest that they are magic-sized and thus termed as single-sized. Nuclear magnetic resonance (NMR), with sensitivity to local environment, provided valuable information regarding the structure and composition of the nanocrystals. Solid-state 13 C cross polarization/ magic angle spinning (CP/MAS) NMR spectra showed that the carboxylate capping ligand is firmly attached to the crystal, and 1 H decoupled 113 Cd MAS spectra, with and without CP, distinguished between the surface Cd species and the Cd inside a nanocrystal. The 113 Cd NMR results also confirmed, unambiguously, that the nanocrystals are homogeneously alloyed ternary CdTeSe, with 113 C...

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confidence: 92%

Section: Introductionmentioning

confidence: 99%

Homogeneously-Alloyed CdTeSe Single-Sized Nanocrystals with Bandgap Photoluminescence

et al. 2009

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“…Researcher have been paying attention to controlled shaped morphology of nanomaterials after growth, particularly solution-phase fabrication of one-dimensional nanostructures of binary semiconductors materials. Nanostructures of metal chalcogenides such as CdS, CdSe, ZnS, SnS, etc., have attracted considerable interest having their application in optical, electronic and superconductor devices [1,2]. Narrow band gap IV-VI (IV = Sn, Ge, Pb; VI = S, Te, Se) semiconductors exhibiting infrared (IR) and near-infrared (NIR) optical activity have been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Synthesis, Characterization and Raman Vibrations of Chalcogenide SnS Nanorods

Ali

Wang

Zafar

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract:One dimensional nanostructure have been considered promising candidates for optoelectronics and energy storage devices. However, cost-effective approach for large-scale production using wet chemical method is still a big challenge. Here, single crystalline monodispersed stannous sulfide (SnS) nanorods in the range of 400nm to micrometer have been synthesized using solution-based method. The morphology of the prepared nanorods was controlled by tuning the parameters, including the concentrations of reagents, reaction time and temperature. The resultant nanorods were characterized using XRD, FESEM, and Raman spectroscopy techniques. Four vibrational modes 141 cm -1 , 165.3 cm -1 , 218 cm -1 and 289.6 cm -1 were observed by Raman spectroscopy, which is consistent with nano orthorhombic SnS herzenbergite phase.

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“…In this context, ultrasmall nanocrystals have the ability to (1) serve as active precursors in the formation of various anisotropic nanostructures, 15,[19][20][21] and (2) undergo fast charge separation and slow recombination. [22][23][24] Despite immense interest in ultrasmall nanocrystals in fundamental chemical processes, only a handful of high temperature [25][26][27] or alkylphosphine [28][29] precursor-based synthetic methods have been developed to prepare them. Very recently, low temperature, nonphosphinated methods for synthesis of ultrasmall CdSe nanocrystals were reported.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

Dolai¹,

Dutta

Muhoberac³

et al. 2015

Chem. Mater.

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ABSTRACT:We have designed a new non-phosphinated reaction pathway, which includes synthesis of a new, highly reactive Se-bridged organic species (chalcogenide precursor), to produce bright white light-emitting ultrasmall CdSe nanocrystals of high quality under mild reaction conditions. The detailed characterization of structural properties of the selenium precursor through combined 77 Se NMR and laser desorption ionization-mass spectrometry (LDI-MS) provided valuable insights into Se release and delineated the nanocrystal formation mechanism at the molecular level. The 1 H NMR study showed that the rate of disappearance of Se-precursor maintained a single-exponential decay with a rate constant of 2.3 x 10 -4 s -1 at room temperature. Furthermore, the combination of LDI-MS and optical spectroscopy was used for the first time to deconvolute the formation mechanism of our bright white light-emitting nanocrystals, which demonstrated initial formation of a smaller key nanocrystal intermediate (CdSe)19. Application of thermal driving force for destabilization resulted in (CdSe)n nanocrystal generation with n = 29-36 through continuous dissolution and addition of monomer onto existing nanocrystals while maintaining a living-polymerization type growth mode. Importantly, our ultrasmall CdSe nanocrystals displayed an unprecedentedly large fluorescence quantum yield of ~27% for this size regime (<2.0 nm diameter). These mixed oleylamine and cadmium benzoate ligand-coated CdSe nanocrystals showed a fluorescence lifetime of ~90 ns, a significantly large value for such small nanocrystals, which was due to delocalization of the exciton wavefunction into the ligand monolayer. We believe our findings will be relevant to formation of other metal chalcogenide nanocrystals through expansion of the understanding and manipulation of surface ligand chemistry, which together will allow the preparation of "artificial solids" with high charge conductivity and mobility for advanced solid-state device applications.3

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White-Light Emission from Magic-Sized Cadmium Selenide Nanocrystals

Cited by 641 publications

References 18 publications

Homogeneously-Alloyed CdTeSe Single-Sized Nanocrystals with Bandgap Photoluminescence

Homogeneously-Alloyed CdTeSe Single-Sized Nanocrystals with Bandgap Photoluminescence

Hydrothermal Synthesis, Characterization and Raman Vibrations of Chalcogenide SnS Nanorods

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

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