Measurement of electronic splitting in PbS quantum dots by two-dimensional nonlinear spectroscopy

Harel, Elad; Rupich, Sara M.; Schaller, Richard D.; Talapin, Dmitri V.; Engel, Gregory S.

doi:10.1103/physrevb.86.075412

Cited by 45 publications

(36 citation statements)

References 23 publications

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“…Except one recent publication 33 , no electronic coherence was reported 24,39 or only with a very fast decoherence time, that is, with oscillations observable mostly within the pulse duration 27 . From the results, it is evident that the pure homogeneous line broadening of the colloidal NPLs enables clear observation of the electronic coherence that is hidden by inhomogeneous dephasing in the case of the CdSe colloidal quantum dots.…”

Section: Discussionmentioning

confidence: 99%

Room-temperature exciton coherence and dephasing in two-dimensional nanostructures

et al. 2015

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Electronic coherence has attracted considerable attention for its possible role in dynamical processes in molecular systems. However, its detection is challenged by inhomogeneous line broadening and interference with vibrational coherences. In particular, reports of 'persistent' coherent exciton superpositions at room temperature remain controversial, as the related transitions give typically shorter optical dephasing times of about 10-20 fs. To rationalize these reported long-lived coherences, several models have been proposed, involving strong correlation in the mechanisms of decoherence or that electronic coherences may be sustained by resonant vibrational modes. Here we report a decisive example of electronic coherence occurring in a chemical system in a 'warm and wet' (room-temperature solution) environment, colloidal semiconductor nanoplatelets, where details are not obscured by vibrational coherences nor ensemble dephasing. Comparing the exciton and optical coherence times evidences a partial correlation of fluctuations underlying dephasing and allows us to elucidate decoherence mechanisms occurring in these samples.

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Section: Discussionmentioning

confidence: 99%

Room-temperature exciton coherence and dephasing in two-dimensional nanostructures

et al. 2015

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“…For example, using 2DES Harel et al have evidenced the rich electronic fi ne structure of the fi rst exciton peak in colloidal PbS quantum dots with large inhomogeneous broadening. [ 83 ] In Figure 2 , we show the 2D spectrum of CdSe/CdS core/shell quantum dots at T = 50 fs and their corresponding linear small 2016, 12, No. 16, 2234-2244 Figure 2.…”

Section: Pauli Exclusion and Exciton-exciton Interactionsmentioning

confidence: 99%

Two‐Dimensional Visible Spectroscopy For Studying Colloidal Semiconductor Nanocrystals

Cassette

Dean

Scholes

2016

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Possibilities offered by 2D visible spectroscopy for the investigation of the properties of excitons in colloidal semiconductor nanocrystals are overviewed, with a particular focus on their ultrafast dynamics. The technique of 2D electronic spectroscopy is illustrated with several examples showing its advantages compared to 1D ultrafast spectroscopic techniques (transient absorption and time-resolved photoluminescence).

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“…The technique has facilitated our understanding of exciton dephasing [22] and relaxation dynamics [23], excitonexciton coherent coupling [24] and electronic properties [25]. In this work, 2DFTS is used to study exciton fine-structure splitting with a spectral resolution determined by the maximum delay between pulses, allowing us to achieve up to 30 neV resolution.…”

Section: Optical 2d Fourier-transform Spectroscopymentioning

confidence: 99%

Correlation and dephasing effects on the non-radiative coherence between bright excitons in an InAs QD ensemble measured with 2D spectroscopy

Singh

Акимов

et al. 2013

Solid State Communications

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Exchange-mediated fine-structure splitting of bright excitons in an ensemble of InAs quantum dots is studied using optical twodimensional Fourier-transform spectroscopy. By monitoring the non-radiative coherence between the bright states, we find that the fine-structure splitting decreases with increasing exciton emission energy at a rate of 0.1 µeV/meV. Dephasing rates are compared to population decay rates to reveal that pure dephasing causes the exciton optical coherences to decay faster than the radiative limit at low temperature, independent of excitation density. Fluctuations of the bright state transition energies are nearly perfectlycorrelated, protecting the non-radiative coherence from interband dephasing mechanisms.

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Measurement of electronic splitting in PbS quantum dots by two-dimensional nonlinear spectroscopy

Cited by 45 publications

References 23 publications

Room-temperature exciton coherence and dephasing in two-dimensional nanostructures

Room-temperature exciton coherence and dephasing in two-dimensional nanostructures

Two‐Dimensional Visible Spectroscopy For Studying Colloidal Semiconductor Nanocrystals

Correlation and dephasing effects on the non-radiative coherence between bright excitons in an InAs QD ensemble measured with 2D spectroscopy

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