Hot electron emission can lead to damping of optomechanical modes in core-shell Ag@TiO2 nanocubes

Sigitas Tamulevičius, Domantas Peckus, Hongpan Rong, Lukas Stankevičius, Mindaugas Juodenas, Tomas Tamulevičius*, Joel Henzie

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Interactions between light and metal nanostructures are mediated by collective excitations of free electrons called surface plasmons, which depend primarily on geometry and dielectric environment. Excitation with ultrafast pulses can excite optomechanical modes that modulate the volume and shape of nanostructures at gigahertz frequencies. Plasmons serve as an optical handle to study the ultrafast electronic dynamics of nanoscale systems. We describe a method to synthesize core-shell Ag@TiO2 nanocubes-while successfully maintaining the size and shape of the nanocube. Transient absorbance spectroscopy (TAS) is used to track photophysical processes on multiple time scales: from the ultrafast creation of hot carriers to their decay into phonons and the formation of optomechanical modes. Surprisingly, the TiO2 shell surrounding the Ag nanocubes caused no appreciable change in the frequency of the optomechanical mode, indicating that mechanical coupling between the core and shell is weak. However, the optomechanical mode was strongly attenuated by the TiO2 shell and TAS decay at ultrafast time scales (0-5 ps) was much faster. This observation suggests that up to-36% of the energy coupled into the plasmon resonance is being lost to the TiO2 as hot carriers instead of coupling to the optomechanical mode. Analysis of both ultrafast decay and characterization of optomechanical modes provides a dual accounting method to track energy dissipation in hybrid metal-semiconductor nanosystems for plasmon-enhanced solar energy conversion and chemical fuel generation.

Original languageEnglish
JournalJournal of Physical Chemistry C
Volume121
Issue number43
Pages (from-to)24159-24167
ISSN1932-7447
DOIs
Publication statusPublished - 2017

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Plasmons
Hot carriers
Hot electrons
Electron emission
hot electrons
electron emission
Nanostructures
Light Metals
Damping
damping
Spectroscopy
Nanosystems
Phonons
Metals
Energy conversion
Solar energy
Energy dissipation
Semiconductor materials
plasmons
Geometry

Cite this

Tamulevičius, Sigitas ; Peckus, Domantas ; Rong, Hongpan ; Stankevičius, Lukas ; Juodenas, Mindaugas ; Tamulevičius, Tomas ; Henzie, Joel. / Hot electron emission can lead to damping of optomechanical modes in core-shell Ag@TiO2 nanocubes. In: Journal of Physical Chemistry C. 2017 ; Vol. 121, No. 43. pp. 24159-24167.
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title = "Hot electron emission can lead to damping of optomechanical modes in core-shell Ag@TiO2 nanocubes",
abstract = "Interactions between light and metal nanostructures are mediated by collective excitations of free electrons called surface plasmons, which depend primarily on geometry and dielectric environment. Excitation with ultrafast pulses can excite optomechanical modes that modulate the volume and shape of nanostructures at gigahertz frequencies. Plasmons serve as an optical handle to study the ultrafast electronic dynamics of nanoscale systems. We describe a method to synthesize core-shell Ag@TiO2 nanocubes-while successfully maintaining the size and shape of the nanocube. Transient absorbance spectroscopy (TAS) is used to track photophysical processes on multiple time scales: from the ultrafast creation of hot carriers to their decay into phonons and the formation of optomechanical modes. Surprisingly, the TiO2 shell surrounding the Ag nanocubes caused no appreciable change in the frequency of the optomechanical mode, indicating that mechanical coupling between the core and shell is weak. However, the optomechanical mode was strongly attenuated by the TiO2 shell and TAS decay at ultrafast time scales (0-5 ps) was much faster. This observation suggests that up to-36{\%} of the energy coupled into the plasmon resonance is being lost to the TiO2 as hot carriers instead of coupling to the optomechanical mode. Analysis of both ultrafast decay and characterization of optomechanical modes provides a dual accounting method to track energy dissipation in hybrid metal-semiconductor nanosystems for plasmon-enhanced solar energy conversion and chemical fuel generation.",
author = "Sigitas Tamulevičius and Domantas Peckus and Hongpan Rong and Lukas Stankevičius and Mindaugas Juodenas and Tomas Tamulevičius and Joel Henzie",
year = "2017",
doi = "10.1021/acs.jpcc.7b06667",
language = "English",
volume = "121",
pages = "24159--24167",
journal = "The Journal of Physical Chemistry Part C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "43",

}

Tamulevičius, S, Peckus, D, Rong, H, Stankevičius, L, Juodenas, M, Tamulevičius, T & Henzie, J 2017, 'Hot electron emission can lead to damping of optomechanical modes in core-shell Ag@TiO2 nanocubes', Journal of Physical Chemistry C, vol. 121, no. 43, pp. 24159-24167. https://doi.org/10.1021/acs.jpcc.7b06667

Hot electron emission can lead to damping of optomechanical modes in core-shell Ag@TiO2 nanocubes. / Tamulevičius, Sigitas; Peckus, Domantas; Rong, Hongpan; Stankevičius, Lukas; Juodenas, Mindaugas; Tamulevičius, Tomas; Henzie, Joel.

In: Journal of Physical Chemistry C, Vol. 121, No. 43, 2017, p. 24159-24167.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Hot electron emission can lead to damping of optomechanical modes in core-shell Ag@TiO2 nanocubes

AU - Tamulevičius, Sigitas

AU - Peckus, Domantas

AU - Rong, Hongpan

AU - Stankevičius, Lukas

AU - Juodenas, Mindaugas

AU - Tamulevičius, Tomas

AU - Henzie, Joel

PY - 2017

Y1 - 2017

N2 - Interactions between light and metal nanostructures are mediated by collective excitations of free electrons called surface plasmons, which depend primarily on geometry and dielectric environment. Excitation with ultrafast pulses can excite optomechanical modes that modulate the volume and shape of nanostructures at gigahertz frequencies. Plasmons serve as an optical handle to study the ultrafast electronic dynamics of nanoscale systems. We describe a method to synthesize core-shell Ag@TiO2 nanocubes-while successfully maintaining the size and shape of the nanocube. Transient absorbance spectroscopy (TAS) is used to track photophysical processes on multiple time scales: from the ultrafast creation of hot carriers to their decay into phonons and the formation of optomechanical modes. Surprisingly, the TiO2 shell surrounding the Ag nanocubes caused no appreciable change in the frequency of the optomechanical mode, indicating that mechanical coupling between the core and shell is weak. However, the optomechanical mode was strongly attenuated by the TiO2 shell and TAS decay at ultrafast time scales (0-5 ps) was much faster. This observation suggests that up to-36% of the energy coupled into the plasmon resonance is being lost to the TiO2 as hot carriers instead of coupling to the optomechanical mode. Analysis of both ultrafast decay and characterization of optomechanical modes provides a dual accounting method to track energy dissipation in hybrid metal-semiconductor nanosystems for plasmon-enhanced solar energy conversion and chemical fuel generation.

AB - Interactions between light and metal nanostructures are mediated by collective excitations of free electrons called surface plasmons, which depend primarily on geometry and dielectric environment. Excitation with ultrafast pulses can excite optomechanical modes that modulate the volume and shape of nanostructures at gigahertz frequencies. Plasmons serve as an optical handle to study the ultrafast electronic dynamics of nanoscale systems. We describe a method to synthesize core-shell Ag@TiO2 nanocubes-while successfully maintaining the size and shape of the nanocube. Transient absorbance spectroscopy (TAS) is used to track photophysical processes on multiple time scales: from the ultrafast creation of hot carriers to their decay into phonons and the formation of optomechanical modes. Surprisingly, the TiO2 shell surrounding the Ag nanocubes caused no appreciable change in the frequency of the optomechanical mode, indicating that mechanical coupling between the core and shell is weak. However, the optomechanical mode was strongly attenuated by the TiO2 shell and TAS decay at ultrafast time scales (0-5 ps) was much faster. This observation suggests that up to-36% of the energy coupled into the plasmon resonance is being lost to the TiO2 as hot carriers instead of coupling to the optomechanical mode. Analysis of both ultrafast decay and characterization of optomechanical modes provides a dual accounting method to track energy dissipation in hybrid metal-semiconductor nanosystems for plasmon-enhanced solar energy conversion and chemical fuel generation.

U2 - 10.1021/acs.jpcc.7b06667

DO - 10.1021/acs.jpcc.7b06667

M3 - Journal article

VL - 121

SP - 24159

EP - 24167

JO - The Journal of Physical Chemistry Part C

JF - The Journal of Physical Chemistry Part C

SN - 1932-7447

IS - 43

ER -