Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals

Valerio Pinchetti, Francesco Meinardi, Andrea Camellini, Gianluca Sirigu, Sotirios Christodoulou, Wan Ki Bae, Francesco De Donato, Liberato Manna, Margherita Zavelani-Rossi, Iwan Moreels, Victor I Klimov, Sergio Brovelli

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Two-color emitting colloidal semiconductor nanocrystals (NCs) are of interest for applications in multimodal imaging, sensing, lighting, and integrated photonics. Dual color emission from core- and shell-related optical transitions has been recently obtained using so-called dot-in-bulk (DiB) CdSe/CdS NCs comprising a quantum-confined CdSe core embedded into an ultrathick (∼7-9 nm) CdS shell. The physical mechanism underlying this behavior is still under debate. While a large shell volume appears to be a necessary condition for dual emission, comparison between various types of thick-shell CdSe/CdS NCs indicates a critical role of the interface "sharpness" and the presence of potential barriers. To elucidate the effect of the interface morphology on the dual emission, we perform side-by-side studies of CdSe/CdS DiB-NCs with nominally identical core and shell dimensions but different structural properties of the core/shell interface arising from the crystal structure of the starting CdSe cores (zincblende vs wurtzite). While both structures exhibit dual emission under comparable pump intensities, NCs with a zincblende core show a faster growth of shell luminescence with excitation fluence and a more readily realized regime of amplified spontaneous emission (ASE) even under "slow" nanosecond excitation. These distinctions can be linked to the structure of the core/shell interface: NCs grown from the zincblende cores contain a ∼3.5 nm thick zincblende CdS interlayer, which separates the core from the wurtzite CdS shell and creates a potential barrier for photoexcited shell holes inhibiting their relaxation into the core. This helps maintain a higher population of shell states and simplifies the realization of dual emission and ASE involving shell-based optical transitions.

Original languageEnglish
Pages (from-to)6877-6887
Number of pages11
JournalACS Nano
Volume10
Issue number7
DOIs
Publication statusPublished - Jul 26 2016

Fingerprint

Optical gain
Nanocrystals
nanocrystals
Color
color
Shells (structures)
zincblende
Optical transitions
Spontaneous emission
optical transition
wurtzite
spontaneous emission
Photonics
Luminescence
Structural properties
Lighting
Crystal structure
Pumps
Semiconductor materials
sharpness

Keywords

  • amplified spontaneous emission
  • core/shell heterostructures
  • dual emission
  • exciton dynamics
  • interface structure
  • nanocrystal quantum dots

ASJC Scopus subject areas

  • Engineering(all)
  • Materials Science(all)
  • Physics and Astronomy(all)

Cite this

Pinchetti, V., Meinardi, F., Camellini, A., Sirigu, G., Christodoulou, S., Bae, W. K., ... Brovelli, S. (2016). Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals. ACS Nano, 10(7), 6877-6887. https://doi.org/10.1021/acsnano.6b02635

Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals. / Pinchetti, Valerio; Meinardi, Francesco; Camellini, Andrea; Sirigu, Gianluca; Christodoulou, Sotirios; Bae, Wan Ki; De Donato, Francesco; Manna, Liberato; Zavelani-Rossi, Margherita; Moreels, Iwan; Klimov, Victor I; Brovelli, Sergio.

In: ACS Nano, Vol. 10, No. 7, 26.07.2016, p. 6877-6887.

Research output: Contribution to journalArticle

Pinchetti, V, Meinardi, F, Camellini, A, Sirigu, G, Christodoulou, S, Bae, WK, De Donato, F, Manna, L, Zavelani-Rossi, M, Moreels, I, Klimov, VI & Brovelli, S 2016, 'Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals', ACS Nano, vol. 10, no. 7, pp. 6877-6887. https://doi.org/10.1021/acsnano.6b02635
Pinchetti, Valerio ; Meinardi, Francesco ; Camellini, Andrea ; Sirigu, Gianluca ; Christodoulou, Sotirios ; Bae, Wan Ki ; De Donato, Francesco ; Manna, Liberato ; Zavelani-Rossi, Margherita ; Moreels, Iwan ; Klimov, Victor I ; Brovelli, Sergio. / Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals. In: ACS Nano. 2016 ; Vol. 10, No. 7. pp. 6877-6887.
@article{eb73d59e83dd44999b7bb5f6c433efc6,
title = "Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals",
abstract = "Two-color emitting colloidal semiconductor nanocrystals (NCs) are of interest for applications in multimodal imaging, sensing, lighting, and integrated photonics. Dual color emission from core- and shell-related optical transitions has been recently obtained using so-called dot-in-bulk (DiB) CdSe/CdS NCs comprising a quantum-confined CdSe core embedded into an ultrathick (∼7-9 nm) CdS shell. The physical mechanism underlying this behavior is still under debate. While a large shell volume appears to be a necessary condition for dual emission, comparison between various types of thick-shell CdSe/CdS NCs indicates a critical role of the interface {"}sharpness{"} and the presence of potential barriers. To elucidate the effect of the interface morphology on the dual emission, we perform side-by-side studies of CdSe/CdS DiB-NCs with nominally identical core and shell dimensions but different structural properties of the core/shell interface arising from the crystal structure of the starting CdSe cores (zincblende vs wurtzite). While both structures exhibit dual emission under comparable pump intensities, NCs with a zincblende core show a faster growth of shell luminescence with excitation fluence and a more readily realized regime of amplified spontaneous emission (ASE) even under {"}slow{"} nanosecond excitation. These distinctions can be linked to the structure of the core/shell interface: NCs grown from the zincblende cores contain a ∼3.5 nm thick zincblende CdS interlayer, which separates the core from the wurtzite CdS shell and creates a potential barrier for photoexcited shell holes inhibiting their relaxation into the core. This helps maintain a higher population of shell states and simplifies the realization of dual emission and ASE involving shell-based optical transitions.",
keywords = "amplified spontaneous emission, core/shell heterostructures, dual emission, exciton dynamics, interface structure, nanocrystal quantum dots",
author = "Valerio Pinchetti and Francesco Meinardi and Andrea Camellini and Gianluca Sirigu and Sotirios Christodoulou and Bae, {Wan Ki} and {De Donato}, Francesco and Liberato Manna and Margherita Zavelani-Rossi and Iwan Moreels and Klimov, {Victor I} and Sergio Brovelli",
year = "2016",
month = "7",
day = "26",
doi = "10.1021/acsnano.6b02635",
language = "English",
volume = "10",
pages = "6877--6887",
journal = "ACS Nano",
issn = "1936-0851",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals

AU - Pinchetti, Valerio

AU - Meinardi, Francesco

AU - Camellini, Andrea

AU - Sirigu, Gianluca

AU - Christodoulou, Sotirios

AU - Bae, Wan Ki

AU - De Donato, Francesco

AU - Manna, Liberato

AU - Zavelani-Rossi, Margherita

AU - Moreels, Iwan

AU - Klimov, Victor I

AU - Brovelli, Sergio

PY - 2016/7/26

Y1 - 2016/7/26

N2 - Two-color emitting colloidal semiconductor nanocrystals (NCs) are of interest for applications in multimodal imaging, sensing, lighting, and integrated photonics. Dual color emission from core- and shell-related optical transitions has been recently obtained using so-called dot-in-bulk (DiB) CdSe/CdS NCs comprising a quantum-confined CdSe core embedded into an ultrathick (∼7-9 nm) CdS shell. The physical mechanism underlying this behavior is still under debate. While a large shell volume appears to be a necessary condition for dual emission, comparison between various types of thick-shell CdSe/CdS NCs indicates a critical role of the interface "sharpness" and the presence of potential barriers. To elucidate the effect of the interface morphology on the dual emission, we perform side-by-side studies of CdSe/CdS DiB-NCs with nominally identical core and shell dimensions but different structural properties of the core/shell interface arising from the crystal structure of the starting CdSe cores (zincblende vs wurtzite). While both structures exhibit dual emission under comparable pump intensities, NCs with a zincblende core show a faster growth of shell luminescence with excitation fluence and a more readily realized regime of amplified spontaneous emission (ASE) even under "slow" nanosecond excitation. These distinctions can be linked to the structure of the core/shell interface: NCs grown from the zincblende cores contain a ∼3.5 nm thick zincblende CdS interlayer, which separates the core from the wurtzite CdS shell and creates a potential barrier for photoexcited shell holes inhibiting their relaxation into the core. This helps maintain a higher population of shell states and simplifies the realization of dual emission and ASE involving shell-based optical transitions.

AB - Two-color emitting colloidal semiconductor nanocrystals (NCs) are of interest for applications in multimodal imaging, sensing, lighting, and integrated photonics. Dual color emission from core- and shell-related optical transitions has been recently obtained using so-called dot-in-bulk (DiB) CdSe/CdS NCs comprising a quantum-confined CdSe core embedded into an ultrathick (∼7-9 nm) CdS shell. The physical mechanism underlying this behavior is still under debate. While a large shell volume appears to be a necessary condition for dual emission, comparison between various types of thick-shell CdSe/CdS NCs indicates a critical role of the interface "sharpness" and the presence of potential barriers. To elucidate the effect of the interface morphology on the dual emission, we perform side-by-side studies of CdSe/CdS DiB-NCs with nominally identical core and shell dimensions but different structural properties of the core/shell interface arising from the crystal structure of the starting CdSe cores (zincblende vs wurtzite). While both structures exhibit dual emission under comparable pump intensities, NCs with a zincblende core show a faster growth of shell luminescence with excitation fluence and a more readily realized regime of amplified spontaneous emission (ASE) even under "slow" nanosecond excitation. These distinctions can be linked to the structure of the core/shell interface: NCs grown from the zincblende cores contain a ∼3.5 nm thick zincblende CdS interlayer, which separates the core from the wurtzite CdS shell and creates a potential barrier for photoexcited shell holes inhibiting their relaxation into the core. This helps maintain a higher population of shell states and simplifies the realization of dual emission and ASE involving shell-based optical transitions.

KW - amplified spontaneous emission

KW - core/shell heterostructures

KW - dual emission

KW - exciton dynamics

KW - interface structure

KW - nanocrystal quantum dots

UR - http://www.scopus.com/inward/record.url?scp=84979982386&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84979982386&partnerID=8YFLogxK

U2 - 10.1021/acsnano.6b02635

DO - 10.1021/acsnano.6b02635

M3 - Article

VL - 10

SP - 6877

EP - 6887

JO - ACS Nano

JF - ACS Nano

SN - 1936-0851

IS - 7

ER -