Density of surface states in colloidal CdSe nanoplatelets

Katsaba, A. V.; Fedyanin, V. V.; Ambrozevich, S. A.; Vitukhnovsky, A. G.; Sokolikova, Maria; Vasiliev, R. B.

doi:10.1134/s1063782615100103

Cited by 10 publications

(3 citation statements)

References 12 publications

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“…This model matches the data much better than a multiexponential fit (Supporting Information, Figure S5). “Delayed emission” on time scales much longer than the intrinsic lifetime of the single-exciton state has been ascribed to temporary charge carrier trapping, until eventual release of the trapped charge resulting in emission (Figure e). − , Indeed, release and radiative recombination of trapped charges in CdSe NPLs is also observable in thermoluminescence experiments …”

Section: Delayed Emission From Core-only Nanoplateletsmentioning

confidence: 99%

“…[24][25][26]28 Indeed, release and radiative recombination of trapped charges in CdSe NPLs is also observable in thermoluminescence experiments. 29 Figure 1f shows the emission spectra of the core-only NPLs at varying delay time from the first nanoseconds (red) to 3 μs after excitation (gray). The solid lines are Lorentzian fits of the line shape (on energy scale; see Supporting Information Figure S2), from which we extract the peak positions and widths.…”

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Temporary Charge Carrier Separation Dominates the Photoluminescence Decay Dynamics of Colloidal CdSe Nanoplatelets

et al. 2016

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Luminescent colloidal CdSe nanoplatelets with atomically defined thicknesses have recently been developed, and their potential for various applications has been shown. To understand their special properties, experiments have until now focused on the relatively short time scales of at most a few nanoseconds. Here, we measure the photoluminescence decay dynamics of colloidal nanoplatelets on time scales up to tens of microseconds. The excited state dynamics are found to be dominated by the slow (∼μs) dynamics of temporary exciton storage in a charge-separated state, previously overlooked. We study the processes of charge carrier separation and exciton recovery in pure CdSe nanoplatelets as well as in core-crown and core-shell CdSe/CdS nanoplatelets with high ensemble quantum yields of 50%, and discuss the implications. Our work highlights the importance of reversible charge carrier trapping and experiments over a wide range of time scales for the understanding of colloidal nanoemitters in general and nanoplatelets in particular.

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Section: Delayed Emission From Core-only Nanoplateletsmentioning

confidence: 99%

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confidence: 99%

Temporary Charge Carrier Separation Dominates the Photoluminescence Decay Dynamics of Colloidal CdSe Nanoplatelets

et al. 2016

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“…The CdS/ZnSe nanocrystals studied in this work are coated with oleic acid. As follows from the previous papers [22][23][24][25], oleic acid deposition on the nanocrystal surface does not lead to complete surface passivation. The ZnSe semiconductor shell at hand functions as a potential barrier and blocks carrier trapping by surface states.…”

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confidence: 66%

Luminescence Degradation Mechanisms in CdS/ZnSe Colloidal Nanocrystals

Zabolotskii

Katsaba

Ambrozevich

et al. 2020

Bull. Lebedev Phys. Inst.

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The results of the study of one-photon processes of optically induced degradation of photoluminescence intensity of CdS/ZnSe nanocrystals are presented, and mechanisms of this degradation are determined. It is shown that the nanocrystal photodegradation process consists of three components. The first degradation component is caused by Auger recombination activation in photoinduced hole trapping by the trap associated with a surface state; a long-term degradation component can be associated with thermally activated chemical bond breaking between a passivating ligand, i.e., oleic acid, and the nanocrystal surface followed by nonradiative recombination channel activation.

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Reversible and Irreversible Degradation of CdS/ZnSe Nanocrystals Capped with Oleic Acid

Zabolotskii

Katsaba

Ambrozevich

et al. 2020

Physica Rapid Research Ltrs

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Single‐photon processes of optically induced degradation of the photoluminescence intensity in CdS/ZnSe nanocrystals (NCs) are investigated, and the mechanisms of this degradation are established. It is demonstrated that three processes contribute to the photodegradation of the NCs. The corresponding characteristic times are of about 9.9 s, 260 s, and 2 h. In these experiments, it is found that the short‐term process in the degradation is caused by the activation of Auger recombination when a photoinduced hole is captured in a surface trap, and the long‐term process can be associated with the temperature‐induced detachment of the ligand (oleic acid) from the NC surface and activation of the non‐radiative relaxation channel. The hole detrapping time is calculated to be 135 s.

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Density of surface states in colloidal CdSe nanoplatelets

Cited by 10 publications

References 12 publications

Temporary Charge Carrier Separation Dominates the Photoluminescence Decay Dynamics of Colloidal CdSe Nanoplatelets

Temporary Charge Carrier Separation Dominates the Photoluminescence Decay Dynamics of Colloidal CdSe Nanoplatelets

Luminescence Degradation Mechanisms in CdS/ZnSe Colloidal Nanocrystals

Reversible and Irreversible Degradation of CdS/ZnSe Nanocrystals Capped with Oleic Acid

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