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 language | English |
|---|---|
| Journal | Nano letters |
| DOIs | |
| Publication status | Published - Jan 1 2019 |
Fingerprint
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 journal › Article
}
TY - JOUR
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
UR - http://www.scopus.com/inward/record.url?scp=85074937175&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85074937175&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.9b03676
DO - 10.1021/acs.nanolett.9b03676
M3 - Article
AN - SCOPUS:85074937175
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
ER -