Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement

Metal-film-coupled nanoparticles with subnanometer particle–film gaps possess an ultrasmall mode volume, responsible for a variety of intriguing phenomena in plasmonic nanophotonics. Due to the large radiative loss associated with dipolar coupling, however, the plasmonic-film-coupled nanocavities us...

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Main Authors: Li, Guang-Can, Zhang, Yong-Liang, Jiang, Jing, Luo, Yu, Lei, Dang Yuan
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2017
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Online Access:https://hdl.handle.net/10356/85807
http://hdl.handle.net/10220/43848
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-858072020-03-07T13:57:29Z Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement Li, Guang-Can Zhang, Yong-Liang Jiang, Jing Luo, Yu Lei, Dang Yuan School of Electrical and Electronic Engineering Metal Nanoparticle Dimer Gap Plasmon Mode Metal-film-coupled nanoparticles with subnanometer particle–film gaps possess an ultrasmall mode volume, responsible for a variety of intriguing phenomena in plasmonic nanophotonics. Due to the large radiative loss associated with dipolar coupling, however, the plasmonic-film-coupled nanocavities usually feature a low-quality factor, setting an ultimate limit of the increased light–matter interaction strength. Here, we demonstrate a plasmonic nanocavity composed of a metal-film-coupled nanoparticle dimer, exhibiting a significantly improved quality factor. Compared to a silica-supported dimer, the spectral line width of the nanocavity plasmon resonance is reduced by a factor of ∼4.6 and is even smaller than its monomer counterpart (∼30% reduction). Comprehensive theoretical analyses reveal that this pronounced resonance narrowing effect can be attributed to intense film-mediated plasmon hybridization between the bonding dipolar and quadrupolar gap modes in the dimer. More importantly, the invoking of the dark quadrupole resonance leads to a giant photoluminescence intensity enhancement (∼200 times) and dramatic emission line-width narrowing (∼4.6 times), compared to the silica-supported dimer. The similar spectral characteristics of the measured plasmonic scattering and photoluminescence emission indicate that the radiative decay of the coupled plasmons in the nanocavity is the origin of the observed photoluminescence, consistent with a proposed phenomenological model. Numerical calculations show that the intensity enhancement is mainly contributed by the dimer–film gap rather than the interparticle gap. These findings not only shed more light on the hybridized interaction between plasmon modes but also deepen the understanding of photoluminescence emission in coupled plasmonic nanostructures. MOE (Min. of Education, S’pore) 2017-10-04T05:33:02Z 2019-12-06T16:10:34Z 2017-10-04T05:33:02Z 2019-12-06T16:10:34Z 2017 Journal Article Li, G.-C., Zhang, Y.-L., Jiang, J., Luo, Y., & Lei, D. Y. (2017). Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement. ACS Nano, 11(3), 3067-3080. 1936-0851 https://hdl.handle.net/10356/85807 http://hdl.handle.net/10220/43848 10.1021/acsnano.7b00048 en ACS Nano © 2017 American Chemical Society.
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Metal Nanoparticle Dimer
Gap Plasmon Mode
spellingShingle Metal Nanoparticle Dimer
Gap Plasmon Mode
Li, Guang-Can
Zhang, Yong-Liang
Jiang, Jing
Luo, Yu
Lei, Dang Yuan
Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement
description Metal-film-coupled nanoparticles with subnanometer particle–film gaps possess an ultrasmall mode volume, responsible for a variety of intriguing phenomena in plasmonic nanophotonics. Due to the large radiative loss associated with dipolar coupling, however, the plasmonic-film-coupled nanocavities usually feature a low-quality factor, setting an ultimate limit of the increased light–matter interaction strength. Here, we demonstrate a plasmonic nanocavity composed of a metal-film-coupled nanoparticle dimer, exhibiting a significantly improved quality factor. Compared to a silica-supported dimer, the spectral line width of the nanocavity plasmon resonance is reduced by a factor of ∼4.6 and is even smaller than its monomer counterpart (∼30% reduction). Comprehensive theoretical analyses reveal that this pronounced resonance narrowing effect can be attributed to intense film-mediated plasmon hybridization between the bonding dipolar and quadrupolar gap modes in the dimer. More importantly, the invoking of the dark quadrupole resonance leads to a giant photoluminescence intensity enhancement (∼200 times) and dramatic emission line-width narrowing (∼4.6 times), compared to the silica-supported dimer. The similar spectral characteristics of the measured plasmonic scattering and photoluminescence emission indicate that the radiative decay of the coupled plasmons in the nanocavity is the origin of the observed photoluminescence, consistent with a proposed phenomenological model. Numerical calculations show that the intensity enhancement is mainly contributed by the dimer–film gap rather than the interparticle gap. These findings not only shed more light on the hybridized interaction between plasmon modes but also deepen the understanding of photoluminescence emission in coupled plasmonic nanostructures.
author2 School of Electrical and Electronic Engineering
author_facet School of Electrical and Electronic Engineering
Li, Guang-Can
Zhang, Yong-Liang
Jiang, Jing
Luo, Yu
Lei, Dang Yuan
format Article
author Li, Guang-Can
Zhang, Yong-Liang
Jiang, Jing
Luo, Yu
Lei, Dang Yuan
author_sort Li, Guang-Can
title Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement
title_short Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement
title_full Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement
title_fullStr Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement
title_full_unstemmed Metal-Substrate-Mediated Plasmon Hybridization in a Nanoparticle Dimer for Photoluminescence Line-Width Shrinking and Intensity Enhancement
title_sort metal-substrate-mediated plasmon hybridization in a nanoparticle dimer for photoluminescence line-width shrinking and intensity enhancement
publishDate 2017
url https://hdl.handle.net/10356/85807
http://hdl.handle.net/10220/43848
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