Symmetry of Annealed Wurtzite CdSe Nanocrystals: Assignment to the C3v Point Group

Shiang, J. J.; Kadavanich, A. V.; Grubbs, Robert K.; Alivisatos, A. Paul

doi:10.1021/j100048a017

Cited by 182 publications

(180 citation statements)

References 4 publications

(6 reference statements)

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“…The deep trap state in CdSe is likely a hole in the surface Se dangling bond. 30 Its short life suggests it is less stabilized by nuclear adjustments than is the conduction-edge band state.…”

Section: Discussionmentioning

confidence: 99%

Single particle versus ensemble average: From power-law intermittency of a single quantum dot to quasistretched exponential fluorescence decay of an ensemble

Tang

Marcus

2005

The Journal of Chemical Physics

122

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Light-induced diffusion-controlled electron transfer is proposed as an underlying mechanism for the intermittency ͑power law and breakdown͒ of a single quantum dot and ensemble-averaged fluorescence decay. The intensity decay can be approximated to a stretched exponential expression. The physical links to the free energy gap, reorganization energy, electronic coupling, and diffusion correlation times are discussed. A procedure is described for extracting these molecular-based parameters from experiments and is demonstrated with examples using existing data.

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Section: Discussionmentioning

confidence: 99%

Single particle versus ensemble average: From power-law intermittency of a single quantum dot to quasistretched exponential fluorescence decay of an ensemble

Tang

Marcus

2005

The Journal of Chemical Physics

122

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“…We construct the CdSe nanocrystals with wurtzite structure corresponding to the typical CdSe nanostructures seen in TEM images. 16 The constructed structures have approximate but not exact C 3V symmetry. The same structures have been used in previous time-independent tight-binding studies.…”

Section: A Tight-binding Model Of Cdse Nanostructurementioning

confidence: 97%

Magneto-optical response of CdSe nanostructures

Chen

Whaley

2004

Phys. Rev. B

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We present theoretical calculations of the Landé g-factors of semiconductor nanostructures using a time-dependent empirical tight-binding method. The eigenenergies and eigenfunctions of the band edge states are calculated as a function of an external magnetic field with the electromagnetic field incorporated into the tight-binding Hamiltonian in a gauge-invariant form. The spin-orbit interaction and magnetic field are treated non-perturbatively. The g-factors are extracted from the energy splitting of the eigenstates induced by the applied magnetic field. Both electron and hole gfactors are investigated for CdSe nanostructures. The size and aspect ratio dependence of g-factors is studied. We observe that the electron g-factors are anisotropic and find that the calculated values agree quantitatively with experimental data. We conclude that the two distinct g-factor values extracted from time resolved Faraday rotation experiments should be assigned to the anisotropic in plane (g ) and out of plane (gz) electron g-factors, rather than to isotropic electron and exciton g-factors. We find that the anisotropy in the electron g-factor depends on the aspect ratio of the nanocrystal. The g-factor anisotropy derived from the wurtzite structure and from the non-unity aspect ratio may cancel each other in some regime. We observe that hole g-factors oscillate as a function of size, due to size dependent mixing between the heavy hole-light hole components of the valence band edge states. Extension to the calculation of exciton g-factors is discussed.

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“…[4][5][6] In the model, the three ''states'' correspond to the valence and conduction band ͑VB and CB͒ manifolds, and localized surface states. Although the details of II-VI semiconductor nanocrystals are quite complex and not completely worked out, 7,8 certain basic facts have emerged. Photoexcitation initially places an electron in an ͑interior͒ CB state.…”

Section: Introductionmentioning

confidence: 99%

Photophysics of size-selected InP nanocrystals: Exciton recombination kinetics

Kim

Wolters

Heath

1996

The Journal of Chemical Physics

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We report here on the size-dependent kinetics of exciton recombination in a III-V quantum dot system, InP. The measurements reported include various frequency dependent quantum yields as a function of temperature, frequency dependent luminescence decay curves, and time-gated emission spectra. This data is fit to a three-state quantum model which has been previously utilized to explain photophysical phenomena in II-VI quantum dots. The initial photoexcitation is assumed to place an electron in a ͑delocalized͒ bulk conduction band state. Activation barriers for trapping and detrapping of the electron to surface states, as well as activation barriers for surface-state radiationless relaxation processes are measured as a function of particle size. The energy barrier to detrapping is found to be the major factor limiting room temperature band-edge luminescence. This barrier increases with decreasing particle size. For 30 Å particles, this barrier is found to be greater than 6 kJ/mol-a barrier which is more than an order of magnitude larger than that previously found for 32 Å CdS nanocrystals.

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Symmetry of Annealed Wurtzite CdSe Nanocrystals: Assignment to the C3v Point Group

Cited by 182 publications

References 4 publications

Single particle versus ensemble average: From power-law intermittency of a single quantum dot to quasistretched exponential fluorescence decay of an ensemble

Single particle versus ensemble average: From power-law intermittency of a single quantum dot to quasistretched exponential fluorescence decay of an ensemble

Magneto-optical response of CdSe nanostructures

Photophysics of size-selected InP nanocrystals: Exciton recombination kinetics

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