Dual-emitting dot-in-bulk cdse/cds nanocrystals with highly emissive core-and shell-based trions sharing the same resident electron

Valerio Pinchetti, Elena V. Shornikova, Gang Qiang, Wan Ki Bae, Francesco Meinardi, Scott A. Crooker, Dmitri R. Yakovlev, Manfred Bayer, Victor I. Klimov, Sergio Brovelli

Research output: Contribution to journalArticle

Abstract

Colloidal CdSe nanocrystals (NCs) overcoated with an ultrathick CdS shell, also known as dot-in-bulk (DiB) structures, can support two types of excitons, one of which is core-localized and the other, shell-localized. In the case of weak "sub-single-exciton" pumping, emission alternates between the core-and shell-related channels, which leads to two-color light. This property makes these structures uniquely suited for a variety of photonic applications as well as ideal model systems for realizing complex excitonic quasi-particles that do not occur in conventional core/shell NCs. Here, we show that the DiB design can enable an unusual regime in which the same long-lived resident electron can endow trionlike characteristics to either of the two excitons of the DiB NC (core-or shell-based). These two spectrally distinct trion states are apparent in the measured photoluminescence (PL) and spin dynamics of core and shell excitons conducted over a wide range of temperatures and applied magnetic fields. Low-Temperature PL measurements indicate that core-and shell-based trions are characterized by a nearly ideal (â 100%) emission quantum yield, suggesting the strong suppression of Auger recombination for both types of excitations. Polarization-resolved PL experiments in magnetic fields of up to 60 T reveal that the core-and the shell-localized trions exhibit remarkably similar spin dynamics, which in both cases are controlled by spin-flip processes involving a heavy hole.

Original languageEnglish
JournalNano letters
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Excitons
Nanocrystals
nanocrystals
Spin dynamics
Photoluminescence
Electrons
excitons
electrons
Magnetic fields
spin dynamics
photoluminescence
Quantum yield
Photonics
Polarization
Color
Temperature
elementary excitations
LDS 751
magnetic fields
pumping

Keywords

  • charged excitons/trions
  • core/shell heterostructures
  • dual emission
  • Nanocrystals
  • spin dynamics

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Dual-emitting dot-in-bulk cdse/cds nanocrystals with highly emissive core-and shell-based trions sharing the same resident electron. / Pinchetti, Valerio; Shornikova, Elena V.; Qiang, Gang; Bae, Wan Ki; Meinardi, Francesco; Crooker, Scott A.; Yakovlev, Dmitri R.; Bayer, Manfred; Klimov, Victor I.; Brovelli, Sergio.

In: Nano letters, 01.01.2019.

Research output: Contribution to journalArticle

Pinchetti, Valerio ; Shornikova, Elena V. ; Qiang, Gang ; Bae, Wan Ki ; Meinardi, Francesco ; Crooker, Scott A. ; Yakovlev, Dmitri R. ; Bayer, Manfred ; Klimov, Victor I. ; Brovelli, Sergio. / Dual-emitting dot-in-bulk cdse/cds nanocrystals with highly emissive core-and shell-based trions sharing the same resident electron. In: Nano letters. 2019.
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abstract = "Colloidal CdSe nanocrystals (NCs) overcoated with an ultrathick CdS shell, also known as dot-in-bulk (DiB) structures, can support two types of excitons, one of which is core-localized and the other, shell-localized. In the case of weak {"}sub-single-exciton{"} pumping, emission alternates between the core-and shell-related channels, which leads to two-color light. This property makes these structures uniquely suited for a variety of photonic applications as well as ideal model systems for realizing complex excitonic quasi-particles that do not occur in conventional core/shell NCs. Here, we show that the DiB design can enable an unusual regime in which the same long-lived resident electron can endow trionlike characteristics to either of the two excitons of the DiB NC (core-or shell-based). These two spectrally distinct trion states are apparent in the measured photoluminescence (PL) and spin dynamics of core and shell excitons conducted over a wide range of temperatures and applied magnetic fields. Low-Temperature PL measurements indicate that core-and shell-based trions are characterized by a nearly ideal ({\^a} 100{\%}) emission quantum yield, suggesting the strong suppression of Auger recombination for both types of excitations. Polarization-resolved PL experiments in magnetic fields of up to 60 T reveal that the core-and the shell-localized trions exhibit remarkably similar spin dynamics, which in both cases are controlled by spin-flip processes involving a heavy hole.",
keywords = "charged excitons/trions, core/shell heterostructures, dual emission, Nanocrystals, spin dynamics",
author = "Valerio Pinchetti and Shornikova, {Elena V.} and Gang Qiang and Bae, {Wan Ki} and Francesco Meinardi and Crooker, {Scott A.} and Yakovlev, {Dmitri R.} and Manfred Bayer and Klimov, {Victor I.} and Sergio Brovelli",
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T1 - Dual-emitting dot-in-bulk cdse/cds nanocrystals with highly emissive core-and shell-based trions sharing the same resident electron

AU - Pinchetti, Valerio

AU - Shornikova, Elena V.

AU - Qiang, Gang

AU - Bae, Wan Ki

AU - Meinardi, Francesco

AU - Crooker, Scott A.

AU - Yakovlev, Dmitri R.

AU - Bayer, Manfred

AU - Klimov, Victor I.

AU - Brovelli, Sergio

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Colloidal CdSe nanocrystals (NCs) overcoated with an ultrathick CdS shell, also known as dot-in-bulk (DiB) structures, can support two types of excitons, one of which is core-localized and the other, shell-localized. In the case of weak "sub-single-exciton" pumping, emission alternates between the core-and shell-related channels, which leads to two-color light. This property makes these structures uniquely suited for a variety of photonic applications as well as ideal model systems for realizing complex excitonic quasi-particles that do not occur in conventional core/shell NCs. Here, we show that the DiB design can enable an unusual regime in which the same long-lived resident electron can endow trionlike characteristics to either of the two excitons of the DiB NC (core-or shell-based). These two spectrally distinct trion states are apparent in the measured photoluminescence (PL) and spin dynamics of core and shell excitons conducted over a wide range of temperatures and applied magnetic fields. Low-Temperature PL measurements indicate that core-and shell-based trions are characterized by a nearly ideal (â 100%) emission quantum yield, suggesting the strong suppression of Auger recombination for both types of excitations. Polarization-resolved PL experiments in magnetic fields of up to 60 T reveal that the core-and the shell-localized trions exhibit remarkably similar spin dynamics, which in both cases are controlled by spin-flip processes involving a heavy hole.

AB - Colloidal CdSe nanocrystals (NCs) overcoated with an ultrathick CdS shell, also known as dot-in-bulk (DiB) structures, can support two types of excitons, one of which is core-localized and the other, shell-localized. In the case of weak "sub-single-exciton" pumping, emission alternates between the core-and shell-related channels, which leads to two-color light. This property makes these structures uniquely suited for a variety of photonic applications as well as ideal model systems for realizing complex excitonic quasi-particles that do not occur in conventional core/shell NCs. Here, we show that the DiB design can enable an unusual regime in which the same long-lived resident electron can endow trionlike characteristics to either of the two excitons of the DiB NC (core-or shell-based). These two spectrally distinct trion states are apparent in the measured photoluminescence (PL) and spin dynamics of core and shell excitons conducted over a wide range of temperatures and applied magnetic fields. Low-Temperature PL measurements indicate that core-and shell-based trions are characterized by a nearly ideal (â 100%) emission quantum yield, suggesting the strong suppression of Auger recombination for both types of excitations. Polarization-resolved PL experiments in magnetic fields of up to 60 T reveal that the core-and the shell-localized trions exhibit remarkably similar spin dynamics, which in both cases are controlled by spin-flip processes involving a heavy hole.

KW - charged excitons/trions

KW - core/shell heterostructures

KW - dual emission

KW - Nanocrystals

KW - spin dynamics

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