Pump-Power Dependence of Coherent Acoustic Phonon Frequencies in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Shuo Dong; Jie Lian; Mark Hyunpong Jhon; Yinthai Chan; Zhi Heng Loh

doi:10.1021/acs.nanolett.7b01394

Pump-Power Dependence of Coherent Acoustic Phonon Frequencies in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Shuo Dong, Jie Lian, Mark Hyunpong Jhon^*, Yinthai Chan, Zhi Heng Loh

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

19 Citations (Scopus)

Abstract

Femtosecond optical pump-probe spectroscopy resolves hitherto unobserved coherent acoustic phonons in colloidal CdSe/CdS core/shell nanoplatelets (NPLs). With increasing pump fluence, the frequency of the in-plane acoustic mode increases from 5.2 to 10.7 cm^-1, whereas the frequency of the out-of-plane mode remains at ∼20 cm^-1. Analysis of the oscillation phases suggests that the coherent acoustic phonon generation mechanism transitions from displacive excitation to subpicosecond Auger hole trapping with increasing pump fluence. The measurements yield Huang-Rhys parameters of ∼10^-2 for both acoustic modes. The weak electron-phonon coupling strengths favor the application of NPLs in optoelectronics.

Original language	English
Pages (from-to)	3312-3319
Number of pages	8
Journal	Nano Letters
Volume	17
Issue number	5
DOIs	https://doi.org/10.1021/acs.nanolett.7b01394
Publication status	Published - May 10 2017
Externally published	Yes

Bibliographical note

Publisher Copyright:
© 2017 American Chemical Society.

ASJC Scopus Subject Areas

Bioengineering
General Chemistry
General Materials Science
Condensed Matter Physics
Mechanical Engineering

Keywords

2D semiconductor nanostructure
acoustic phonon
Auger hole trapping
femtosecond transient absorption spectroscopy
Vibrational wave packet

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10.1021/acs.nanolett.7b01394

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title = "Pump-Power Dependence of Coherent Acoustic Phonon Frequencies in Colloidal CdSe/CdS Core/Shell Nanoplatelets",

abstract = "Femtosecond optical pump-probe spectroscopy resolves hitherto unobserved coherent acoustic phonons in colloidal CdSe/CdS core/shell nanoplatelets (NPLs). With increasing pump fluence, the frequency of the in-plane acoustic mode increases from 5.2 to 10.7 cm-1, whereas the frequency of the out-of-plane mode remains at ∼20 cm-1. Analysis of the oscillation phases suggests that the coherent acoustic phonon generation mechanism transitions from displacive excitation to subpicosecond Auger hole trapping with increasing pump fluence. The measurements yield Huang-Rhys parameters of ∼10-2 for both acoustic modes. The weak electron-phonon coupling strengths favor the application of NPLs in optoelectronics.",

keywords = "2D semiconductor nanostructure, acoustic phonon, Auger hole trapping, femtosecond transient absorption spectroscopy, Vibrational wave packet",

author = "Shuo Dong and Jie Lian and Jhon, {Mark Hyunpong} and Yinthai Chan and Loh, {Zhi Heng}",

note = "Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

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doi = "10.1021/acs.nanolett.7b01394",

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T1 - Pump-Power Dependence of Coherent Acoustic Phonon Frequencies in Colloidal CdSe/CdS Core/Shell Nanoplatelets

AU - Dong, Shuo

AU - Lian, Jie

AU - Jhon, Mark Hyunpong

AU - Chan, Yinthai

AU - Loh, Zhi Heng

PY - 2017/5/10

Y1 - 2017/5/10

N2 - Femtosecond optical pump-probe spectroscopy resolves hitherto unobserved coherent acoustic phonons in colloidal CdSe/CdS core/shell nanoplatelets (NPLs). With increasing pump fluence, the frequency of the in-plane acoustic mode increases from 5.2 to 10.7 cm-1, whereas the frequency of the out-of-plane mode remains at ∼20 cm-1. Analysis of the oscillation phases suggests that the coherent acoustic phonon generation mechanism transitions from displacive excitation to subpicosecond Auger hole trapping with increasing pump fluence. The measurements yield Huang-Rhys parameters of ∼10-2 for both acoustic modes. The weak electron-phonon coupling strengths favor the application of NPLs in optoelectronics.

AB - Femtosecond optical pump-probe spectroscopy resolves hitherto unobserved coherent acoustic phonons in colloidal CdSe/CdS core/shell nanoplatelets (NPLs). With increasing pump fluence, the frequency of the in-plane acoustic mode increases from 5.2 to 10.7 cm-1, whereas the frequency of the out-of-plane mode remains at ∼20 cm-1. Analysis of the oscillation phases suggests that the coherent acoustic phonon generation mechanism transitions from displacive excitation to subpicosecond Auger hole trapping with increasing pump fluence. The measurements yield Huang-Rhys parameters of ∼10-2 for both acoustic modes. The weak electron-phonon coupling strengths favor the application of NPLs in optoelectronics.

KW - 2D semiconductor nanostructure

KW - acoustic phonon

KW - Auger hole trapping

KW - femtosecond transient absorption spectroscopy

KW - Vibrational wave packet

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Pump-Power Dependence of Coherent Acoustic Phonon Frequencies in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Abstract

Bibliographical note

ASJC Scopus Subject Areas

Keywords

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