Fluorescence Decay Time of Single Semiconductor Nanocrystals

Schlegel, Germar; Bohnenberger, Jolanta; Potapova, Inga; Mews, Alf

doi:10.1103/physrevlett.88.137401

Cited by 441 publications

(498 citation statements)

References 21 publications

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“…Other multiexponential models are the heuristic biexponential model and the Kohlrausch stretched exponential model that has been employed to QDs outside photonic crystals. 22,24 Figure 2 shows that the biexponential model does not match our data, even though more free parameters are involved. The stretched exponential model does not match our data either, 23 which again confirms that the variations we observe are due to LDOS effects in photonic crystals and not to complex emission properties of the QDs.…”

Section: Resultsmentioning

confidence: 89%

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Strongly nonexponential time-resolved fluorescence of quantum-dot ensembles in three-dimensional photonic crystals

et al. 2007

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We observe experimentally that ensembles of quantum dots in three-dimensional (3D) photonic crystals reveal strongly nonexponential time-resolved emission. These complex emission decay curves are analyzed with a continuous distribution of decay rates. The log-normal distribution describes the decays well for all studied lattice parameters. The distribution width is identified with variations of the radiative emission rates of quantum dots with various positions and dipole orientations in the unit cell. We find a striking sixfold change of the width of the distribution by varying the lattice parameter. This interpretation qualitatively agrees with the calculations of the 3D projected local density of states. We therefore conclude that fluorescence decay of ensembles of quantum dots is highly nonexponential to an extent that is controlled by photonic crystals.

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Section: Resultsmentioning

confidence: 89%

“…͑iv͒ It was suggested in Ref. 22 that temporal fluctuations of the environment surrounding the QDs induce a distribution of nonradiative decay channels. In our experiments,…”

Section: Resultsmentioning

confidence: 99%

Strongly nonexponential time-resolved fluorescence of quantum-dot ensembles in three-dimensional photonic crystals

et al. 2007

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“…40 In the case of simple biexponential analysis it is assumed that each dot's emission lifetime is made up of two components 41,42 and the shorter lifetime,  1 , is typically attributed to the intrinsic recombination of the initially populated core states. [43][44][45][46] The origin of the longer component  2 , although long disputed, is now considered to be a result of the interference of surface states (i.e. the presence or absence of surface defects), with the recombination of the electron-hole pairs.…”

Section: Discussionmentioning

confidence: 99%

Synthesis and spectroscopic studies of chiral CdSe quantum dots

et al. 2010

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Using microwave irradiation, water soluble, optically active, penicillamine (Pen) capped CdSe nanocrystals with broad spectral distribution (430-780 nm) of photoluminescence have been produced and studied by a range of instrumental techniques including absorption, circular dichroism and both steady state and time resolved photoluminescence spectroscopy. The photoluminescence of these nanocrystals is attributed to emission from surface defect states. The decay of the excited state in the nanosecond region, which can be analysed as a triple exponential, depends strongly on the emission wavelength selected, but only weakly on the excitation wavelength. Graphical Abstract: IntroductionChirality is a common occurrence in the natural world and chiraln compounds are very important in chemistry, biology, pharmacology and medicine. It has also been envisaged that chirality could play an important role in nanotechnology. 1,2 The majority of existing research in this field has been focused on chiral organic, metallorganic and biological molecules and their supramolecular structures, 3 while research in the area of chiral inorganic nanoparticles is still in the very early stage of its development. For example, there has been some work involving chiral optically active metallic gold 4,5 and silver 6,7 nanoparticles, as well as carbon nanotubes. 8,9 However, there are currently only a few recent papers dealing with chiral light emitting semiconducting nanocrystals (quantum dots). [10][11][12][13][14] In general over the last decade much attention has been directed towards II-VI type CdS, CdTe and CdSe quantum dots (QDs). [15][16][17][18][19] It is the ability to fine-tune their optical properties by chemical control of their size and shape (i.e. their degree of quantum confinement) which makes quantum dots particularly interesting. This level of optical control combined with QDs' resistance to photobleaching and their high level of solubility in practically any solvent (depending on the stabiliser used) make these nanomaterials potentially suited for roles as divergent as light emitting diodes, 20 biological sensors 21 and photovoltaic devices. [22][23][24] Thiol group containing amino acids have proved to be excellent stabilisers, with L-cysteine becoming one of the popular surface capping molecules for CdX (X ¼ S, Se, and Te) nanoparticles. 18,[25][26][27][28][29][30][31] In addition this use of stereospecific chiral stabilising molecules opened another avenue of interest in the area of quantum dot research, as chirality is a key factor in biological and biochemical interactions. Due to their unique photophysical properties, we believe that chiral QDs have a range of potential applications in photonics and biochemistry. 13,32,33 The main aim of our work is to develop novel chiral CdSe based QDs by using chiral stabilisers and to investigate the properties of these materials. Here we report the synthesis and detailed spectroscopic studies of new penicillamine stabilised CdSe QDs, which have been prepared using the dextrorota...

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“…The trend that could be extrapolated, based on the few available experimental data [19][20][21][22][23] for NQDs of different sizes, was that of a slight decrease of the radiative lifetime with increasing dot size. However, a recent experimental paper by van Driel et al [18] showed an increase of the radiative lifetime with size for CdSe quantum dots at room temperature (see Fig.…”

Section: Size-dependence Of the Exciton Radiative Lifetime And Commentioning

confidence: 99%

Lifetime and polarization of the radiative decay of excitons, biexcitons, and trions in CdSe nanocrystal quantum dots

2007

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Using the pseudopotential configuration-interaction method, we calculate the intrinsic lifetime and polarization of the radiative decay of single excitons (X), positive and negative trions (X + and X -), and biexcitons (XX) in CdSe nanocrystal quantum dots. We investigate the effects of the inclusion of increasingly more complex many-body treatments, starting from the single-particle approach and culminating with the configuration interaction scheme. Our configuration-interaction results for the size dependence of the single-exciton radiative lifetime at room temperature are in excellent agreement with recent experimental data. We also find that (i) whereas the polarization of the bright exciton emission is always perpendicular to the hexagonal c axis, the polarization of the dark exciton switches

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Fluorescence Decay Time of Single Semiconductor Nanocrystals

Cited by 441 publications

References 21 publications

Strongly nonexponential time-resolved fluorescence of quantum-dot ensembles in three-dimensional photonic crystals

Strongly nonexponential time-resolved fluorescence of quantum-dot ensembles in three-dimensional photonic crystals

Synthesis and spectroscopic studies of chiral CdSe quantum dots

Lifetime and polarization of the radiative decay of excitons, biexcitons, and trions in CdSe nanocrystal quantum dots

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