Probing the Local Site Environments in Mn:CdSe Quantum Dots

Zheng, Weiwei; Wang, Zhenxing; Wright, Joshua; Goundie, Ben; Dalal, Naresh S.; Meulenberg, Robert W.; Strouse, Geoffrey F.

doi:10.1021/jp2082215

Cited by 52 publications

(92 citation statements)

References 62 publications

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“…21 Magnetic properties of Mn-doped CdSe QDs were probed by EPR over a wide range of QD diameters. 22,23 The EPR spectra of Mn-doped CdSe QDs with low concentrations of Mn contain sextet features which correspond to the total spin magnetic moment of 5 µ B and oxidation state of +2 for the dopant atoms.…”

Section: Introductionmentioning

confidence: 99%

Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

Gutsev

Weatherford

Ramachandran

et al. 2015

The Journal of Chemical Physics

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Photoelectron spectra of the Mnn(-) anion clusters (n = 2-16) are obtained by anion photoelectron spectroscopy. The electronic and geometrical structures of the anions are computed using density functional theory with generalized gradient approximation and a basis set of triple-ζ quality. The electronic and geometrical structures of the neutral Mnn clusters have also been computed to estimate the adiabatic electron affinities. The average absolute difference between the computed and experimental vertical detachment energies of an extra electron is about 0.2 eV. Beginning with n = 6, all lowest total energy states of the Mnn(-) anions are ferrimagnetic with the spin multiplicities which do not exceed 8. The computed ionization energies of the neutral Mnn clusters are in good agreement with previously obtained experimental data. According to the results of our computations, the binding energies of Mn atoms are nearly independent on the cluster charge for n > 6 and possess prominent peaks at Mn13 and Mn13(-) in the neutral and anionic series, respectively. The density of states obtained from the results of our computations for the Mnn(-) anion clusters show the metallic character of the anion electronic structures.

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Section: Introductionmentioning

confidence: 99%

Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

Gutsev

Weatherford

Ramachandran

et al. 2015

The Journal of Chemical Physics

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“…[6][7][8] A ferromagnetic state can be stabilized, for example, by co-doping of a QD with such atoms as Li. 9 Magnetic properties of Mn-doped CdSe QDs were probed with the EPR method in the range of 1.3 nm to 6 nm in diameter 10,11 as well for larger diameters. 12 The EPR spectra of Mndoped CdSe QDs contain sextet features which correspond to the total spin of 2.5 and oxidation state of +2 of the dopant atoms.…”

Section: Introductionmentioning

confidence: 99%

Structure and Properties of a (CdSe)₆@(CdSe)₃₀Cluster Doped with Mn Atoms

2015

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The structure and properties of a (CdSe) 6 @(CdSe) 30 cluster doped with one or two Mn atoms are studied using density functional theory. Geometrical structure optimizations are performed using relativistic effective core potentials for Se and Cd atoms and with an all-electron description for Mn atoms. The (CdSe) 6 core corresponds to a zinc blende bulk-type structure and each shell atom is connected to three atoms of the opposite type. We considered different Mn-substitutions of a single Se and Cd atom, substitutions of two Cd atoms with two Mn atoms, as well as additions of one and two Mn atoms to the (CdSe) 6 @(CdSe) 30 cluster. We found that an antiferromagnetic singlet state of the Mn 2 Cd 4 Se 6 @(CdSe) 30 cluster possesses the Fermi contact coupling constants which are close in the absolute value to the experimental ESR value. In the Cd-substituted clusters, the binding energies of Mn atoms are found to be appreciably larger than the binding energies of Cd atoms in the initial cluster, which explains the high miscibility of Mn in bulk CdSe. Experimental observations of drastic changes in the magnetic behavior of Mndoped Q-dots after the annealing can be explained from the results of our calculations of total energy as a function of total spin.

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“…3c and d) also exhibit networks of hyperbranched particles. 48 The estimated value is substantially smaller than that of surface Mn 2+ (~90 G), 13,14,49 further affirming Mn 2+ incorporation. For both 2 and 3a, smaller particles with more rounded, thicker arms are observed.…”

Section: Morphology and Structure Of Mn 2+ :Znse1-xsx Nanocrystalsmentioning

confidence: 82%

“…1,2 The availability of luminescent colloidal nanocrystals (NCs) of these materials expanded their use to bioimaging and sensing, [3][4][5] and solar energy, 6-8 among other applications. [11][12][13][14] Applications involving Mn 2+ phosphorescence involve doping of wide bandgap semiconductors. [11][12][13][14] Applications involving Mn 2+ phosphorescence involve doping of wide bandgap semiconductors.…”

Section: Introductionmentioning

confidence: 99%

Single-step synthesis of hyperbranched, luminescent Mn²⁺-doped ZnSe_1−xS_x nanocrystals using dichalcogenide precursors

2016

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Taking advantage of dichalcogenide precursors, a simple, single-step heat-up method for obtaining Mn 2+ -doped ZnSe1-xSx nanocrystals (NCs) is presented. Tuning the ratios of diselendide and disulfide precursors results in alloys with varying shape, size and composition. When diphenyldiselenide (Ph2Se2) is used, highly branched networks of small NCs form. Dimethydisulfide (Me2S2) induces formation of larger NCs with less branching. Mixtures of the two exhibit branching proportional to the amount of Ph2Se2 vs Me2S2, allowing formation of a series of branched Mn 2+ -doped NCs. Interestingly, these NCs exhibit photoluminescence (PL) characteristic of Mn 2+ , despite the large number of defects and unusual shapes they possess. This demonstrates Mn 2+ can be successfully doped into NCs with several degrees of branching, in which it acts as an efficient radiative trap. Addition of thiol to the NCs led to a large enhancement in the Mn 2+ PL. In organic solution, the sensitivity to thiol varied with the degree of NC branching, with hyperbranching NCs giving the most sensitive response. After transfer to aqueous solution, the Mn 2+ PL of the hyperbranched NCs increased dramatically in response to M concentrations of dithiothreitol (DTT).

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Probing the Local Site Environments in Mn:CdSe Quantum Dots

Cited by 52 publications

References 62 publications

Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

Structure and Properties of a (CdSe)₆@(CdSe)₃₀Cluster Doped with Mn Atoms

Single-step synthesis of hyperbranched, luminescent Mn²⁺-doped ZnSe_1−xS_x nanocrystals using dichalcogenide precursors

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Probing the Local Site Environments in Mn:CdSe Quantum Dots

Cited by 52 publications

References 62 publications

Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

Photoelectron spectra and structure of the Mnn− anions (n = 2–16)

Structure and Properties of a (CdSe)6@(CdSe)30Cluster Doped with Mn Atoms

Single-step synthesis of hyperbranched, luminescent Mn2+-doped ZnSe1−xSx nanocrystals using dichalcogenide precursors

Contact Info

Product

Resources

About

Structure and Properties of a (CdSe)₆@(CdSe)₃₀Cluster Doped with Mn Atoms

Single-step synthesis of hyperbranched, luminescent Mn²⁺-doped ZnSe_1−xS_x nanocrystals using dichalcogenide precursors