Probing Purcell enhancement in plasmonic nanoantennas by broadband luminescent Si quantum dots

Sugimoto, Hiroshi; Yashima, Shiho; Furuta, Kenta; Inoue, Asuka; Fujii, Minoru

doi:10.1063/1.4953829

Cited by 7 publications

(5 citation statements)

References 27 publications

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“…To control the gap length precisely, we employ a monolayer of a colloidal solution of silicon (Si) QDs of 3.0 nm in diameter. ,, By controlling the number of QD monolayers from 0 to 4, the gap length is varied from 0 to 12 nm (see Figure S2 in the Supporting Information). In this work, the QD monolayers work not only as the dielectric spacer but also as a stable fluorophore to monitor the Purcell effect in the gap resonator . An advantage to use Si QDs as a fluorophore is the very broad luminescence band with a full width at half-maximum (fwhm) more than 300 meV, which allows us to monitor the Purcell effect in a wide wavelength range.…”

Section: Resultsmentioning

confidence: 99%

“…28 In this work, the QD monolayers work not only as the dielectric spacer but also as a stable fluorophore to monitor the Purcell effect in the gap resonator. 37 An advantage to use Si QDs as a fluorophore is the very broad luminescence band with a full width at halfmaximum (fwhm) more than 300 meV, 37 which allows us to monitor the Purcell effect in a wide wavelength range. Finally, a diluted colloidal solution of Au nanorods (45 nm in diameter and 125 nm in length; transmission electron microscope image in Figure 3a) is dropped to finalize the NRoM structure.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Hybridized Plasmonic Gap Mode of Gold Nanorod on Mirror Nanoantenna for Spectrally Tailored Fluorescence Enhancement

2018

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Plasmonic nanoparticle on mirror antennas with sub-10 nm gaps have shown the great potential in nanophotonic applications because they offer tightly confined electric field in the gap and resultant large Purcell factors. However, in a nanosphere on mirror (NSoM) structure being studied experimentally, the degree of freedom of the antennas in terms of spectral and polarization control is limited. In this work, we report spectral shaping and polarization control of Purcell-enhanced fluorescence by the gap plasmon modes of an anisotropic gold (Au) nanorod on a mirror (NRoM) antenna. Systematic numerical calculations demonstrate the richer resonance behaviors of a NRoM antenna than a NSoM antenna due to the hybridization of the bright and dark modes. We fabricate a NRoM antenna by placing a Au NR on an ultraflat Au film via a mono-, double-, or quadruple-layers of light emitting quantum dots (QDs) (3 nm in diameter). The scattering spectra of single NRoM antennas coincide very well with those of the numerical simulations. We demonstrate large enhancement (>900-fold) and strong shaping of the luminescence from QDs in the gap due to the coupling with the hybridized mode of a NRoM antenna. We also show that the polarization property of the emission is controlled by that of the mode coupled.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Hybridized Plasmonic Gap Mode of Gold Nanorod on Mirror Nanoantenna for Spectrally Tailored Fluorescence Enhancement

2018

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“…Nanosphere lithography (NSL), which uses a self-aligned 2-dimensional array of polystyrene or silica spheres as a template for the formation of metal nanostructures, is one of the high-throughput and low-cost processes to produce metal nanostructures on a large substrate without using expensive equipment. [17][18][19][20][21][22][23][24][25] A template of a sphere array is also used in a metal film over nanosphere (FON) process, in which a relatively thick metal film is deposited on the sphere array to produce metal nanostructures. 22,23,25 Similar to the FON process, a metal film is deposited on a structured substrate fabricated by nanoimprint lithography (NIL) to produce metal nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Gold nanopillar array with sharp surface plasmon resonances and the application in immunoassay

Yanagawa

Hinamoto

Kanno

et al. 2019

Journal of Applied Physics

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Nanoimprinting followed by metal deposition is a low-cost, high-throughput, and highly reproducible process for the fabrication of large-size plasmonic substrates required for commercial products. However, the plasmonic substrates prepared by the process usually have very broad surface plasmon resonances, which cannot be well reproduced by numerical simulations. The poor agreement between experiments and calculations has prevented the detailed analysis of the field enhancement behavior and the improvement of the performance as plasmonic substrates. In this work, we demonstrate that large-area plasmonic substrates with sharp surface plasmon resonances, which can be well reproduced by numerical simulations, are produced by sputter-deposition of gold (Au) on a commercially available nanoimprinted substrate. The good agreement between experiments and simulations allow us to identify the locations and field distributions of the hot spots. The angle dependence of specular reflectance and diffuse reflectance measurements in combination with numerical simulations reveal that a dipolelike bright mode and a higher-order dark mode exist at gaps between Au nanorods. Finally, we demonstrate the application of the developed plasmonic substrates for surface-enhanced fluorescence in sandwich immunoassays for the detection of influenza virus nucleoprotein. We show that the sharp resonance and the capability of precise tuning of the resonance wavelength significantly enhance the luminescence signal.

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“…15 Furthermore, by tuning the surface plasmon resonance wavelength to the emission wavelength of Si-QDs, Purcell enhancement of the emission rate has been reported. [16][17][18][19] In previous studies on surface plasmon enhanced emission of QDs, metal nanostructures have been produced by several different methods. [20][21][22][23][24] The most widely used process is electron-beam lithography, 12,13,25 which is suitable for the proof-of-concept experiments due to the high accuracy of the fabrication process, although it is very costly.…”

Section: Introductionmentioning

confidence: 99%

“…[20][21][22][23][24] The most widely used process is electron-beam lithography, 12,13,25 which is suitable for the proof-of-concept experiments due to the high accuracy of the fabrication process, although it is very costly. Another often used process is nanosphere lithography, 14,15,18 which uses a two-dimensional array of spheres as a template for the formation of metal nanostructures. Although the process is simple and does not require expensive setups for the formation of metal nanostructures, the freedom of the design, and thus the tunability of the surface plasmon resonance wavelength, is limited.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence enhancement of silicon quantum dot monolayer by plasmonic substrate fabricated by nano-imprint lithography

Yanagawa

Inoue

Sugimoto

et al. 2017

Journal of Applied Physics

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Near-field coupling between a silicon quantum dot (Si-QD) monolayer and a plasmonic substrate fabricated by nano-imprint lithography and having broad multiple resonances in the near-infrared (NIR) window of biological substances was studied by precisely controlling the QDs-substrate distance. A strong enhancement of the NIR photoluminescence (PL) of Si-QDs was observed. Detailed analyses of the PL and PL excitation spectra, the PL decay dynamics, and the reflectance spectra revealed that both the excitation cross-sections and the emission rates are enhanced by the surface plasmon resonances, thanks to the broad multiple resonances of the plasmonic substrate, and that the relative contribution of the two enhancement processes depends strongly on the excitation wavelength. Under excitation by short wavelength photons (405 nm), where enhancement of the excitation cross-section is not expected, the maximum enhancement was obtained when the QDs-substrate distance was around 30 nm. On the other hand, under long wavelength excitation (641 nm), where strong excitation cross-section enhancement is expected, the largest enhancement was obtained when the distance was minimum (around 1 nm). The achievement of efficient excitation of NIR luminescence of Si-QDs by long wavelength photons paves the way for the development of Si-QD-based fluorescence bio-sensing devices with a high bound-to-free ratio.

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Probing Purcell enhancement in plasmonic nanoantennas by broadband luminescent Si quantum dots

Cited by 7 publications

References 27 publications

Hybridized Plasmonic Gap Mode of Gold Nanorod on Mirror Nanoantenna for Spectrally Tailored Fluorescence Enhancement

Hybridized Plasmonic Gap Mode of Gold Nanorod on Mirror Nanoantenna for Spectrally Tailored Fluorescence Enhancement

Gold nanopillar array with sharp surface plasmon resonances and the application in immunoassay

Photoluminescence enhancement of silicon quantum dot monolayer by plasmonic substrate fabricated by nano-imprint lithography

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