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Preparation of plasmonic platforms of silver wires on gold mirrors and their application to surface enhanced fluorescence.

Shtoyko T, Raut S, Rich RM, Sronce RJ, Fudala R, Mason RN, Akopova I, Gryczynski Z, Gryczynski I - ACS Appl Mater Interfaces (2014)

Bottom Line: Silica protected gold mirrors were drop-coated with a solution of silver triangular nanoprisms.The triangular nanoprisms were slowly air-dried to get silver wires that self-assembled on the gold mirrors.The lifetime of Me-ADOTA · Cl dye was significantly reduced (∼ 4 times) in the presence of SWs.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, The University of Texas at Tyler , 3900 University Boulevard, Tyler, Texas 75799, United States.

ABSTRACT
In this report we describe a preparation of silver wires (SWs) on gold mirrors and its application to surface enhanced fluorescence (SEF) using a new methodology. Silica protected gold mirrors were drop-coated with a solution of silver triangular nanoprisms. The triangular nanoprisms were slowly air-dried to get silver wires that self-assembled on the gold mirrors. Fluorescence enhancement was studied using methyl azadioxatriangulenium chloride (Me-ADOTA · Cl) dye in PVA spin-coated on a clean glass coverslip. New Plasmonic Platforms (PPs) were assembled by placing a mirror with SWs in contact with a glass coverslip spin-coated with a uniform Me-ADOTA · Cl film. It was shown that surface enhanced fluorescence is a real phenomenon, not just an enhancement of the fluorescence signal due to an accumulation of the fluorophore on rough nanostructure surfaces. The average fluorescence enhancement was found to be about 15-fold. The lifetime of Me-ADOTA · Cl dye was significantly reduced (∼ 4 times) in the presence of SWs. Moreover, fluorescence enhancement and lifetime did not show any dependence on the excitation light polarization.

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Panels A and B show thelifetime image and lifetime histogram, respectively, of Me-ADOTA·Clbetween plain glass slides. C and D show the lifetime image and thelifetime histogram, respectively, of Me-ADOTA·Cl between plainglass and the silica protected gold mirror.
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fig5: Panels A and B show thelifetime image and lifetime histogram, respectively, of Me-ADOTA·Clbetween plain glass slides. C and D show the lifetime image and thelifetime histogram, respectively, of Me-ADOTA·Cl between plainglass and the silica protected gold mirror.

Mentions: Furthermore, in orderto validate these results, measurements were performed with all theappropriate control samples. First, Me-ADOTA·Cl on plain glasswas tested, followed by Me-ADOTA·Cl on the silica protected goldmirror. Figure 5 shows the fluorescence lifetimeimages (FLIM) and fluorescence lifetime distribution histograms (intensityweighted averaging) of respective samples of Me-ADOTA·Cl on plainglass and on the silica protected gold film. As expected, plain glassgives the monoexponential decay with a lifetime of 16 ns (panels Aand B). Me-ADOTA·Cl on the silica protected gold mirror showedheterogeneous (three exponential fit: τ1, 19.8 ±0.21 ns; amplitude, 0.61; τ2, 6.13 ± 0.17 ns;amplitude, 0.30; and τ3, 1.13 ± 0.07 ns; amplitude,0.09) fluorescence decay due to gold induced quenching with averagelifetime of 14.2 ns (panels C and D). Only part of the populationwas quenched, possibly due to the 5 nm silica layer on the gold film.Figure 6 shows the FLIM images of Me-ADOTA·Clon SWs and of the control experiment. Figure 6A shows the FLIM image of the Me-ADOTA·Cl sample put in contactbetween plain glass and SWs on the silica protected gold film on aglass slide (test sample). Figure 6B showsthe lifetime histogram of the image. The blue color in the image isassociated with the shorter lifetime on the lifetime scale, and asshown in histogram, the average lifetime is 3.6 ns. Moreover, we wantedto determine if there is any effect of orientation of excitation lightpolarization on the intensity and the lifetime. We found that changingthe excitation light polarization did not affect the total intensitycounts or fluorescence lifetime of ADOTA in SW deposited on silicaprotected gold mirror (see Supporting Information). This is due to the random orientation of dye molecules on glasscoverslip which leads to depolarized emission.


Preparation of plasmonic platforms of silver wires on gold mirrors and their application to surface enhanced fluorescence.

Shtoyko T, Raut S, Rich RM, Sronce RJ, Fudala R, Mason RN, Akopova I, Gryczynski Z, Gryczynski I - ACS Appl Mater Interfaces (2014)

Panels A and B show thelifetime image and lifetime histogram, respectively, of Me-ADOTA·Clbetween plain glass slides. C and D show the lifetime image and thelifetime histogram, respectively, of Me-ADOTA·Cl between plainglass and the silica protected gold mirror.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4232249&req=5

fig5: Panels A and B show thelifetime image and lifetime histogram, respectively, of Me-ADOTA·Clbetween plain glass slides. C and D show the lifetime image and thelifetime histogram, respectively, of Me-ADOTA·Cl between plainglass and the silica protected gold mirror.
Mentions: Furthermore, in orderto validate these results, measurements were performed with all theappropriate control samples. First, Me-ADOTA·Cl on plain glasswas tested, followed by Me-ADOTA·Cl on the silica protected goldmirror. Figure 5 shows the fluorescence lifetimeimages (FLIM) and fluorescence lifetime distribution histograms (intensityweighted averaging) of respective samples of Me-ADOTA·Cl on plainglass and on the silica protected gold film. As expected, plain glassgives the monoexponential decay with a lifetime of 16 ns (panels Aand B). Me-ADOTA·Cl on the silica protected gold mirror showedheterogeneous (three exponential fit: τ1, 19.8 ±0.21 ns; amplitude, 0.61; τ2, 6.13 ± 0.17 ns;amplitude, 0.30; and τ3, 1.13 ± 0.07 ns; amplitude,0.09) fluorescence decay due to gold induced quenching with averagelifetime of 14.2 ns (panels C and D). Only part of the populationwas quenched, possibly due to the 5 nm silica layer on the gold film.Figure 6 shows the FLIM images of Me-ADOTA·Clon SWs and of the control experiment. Figure 6A shows the FLIM image of the Me-ADOTA·Cl sample put in contactbetween plain glass and SWs on the silica protected gold film on aglass slide (test sample). Figure 6B showsthe lifetime histogram of the image. The blue color in the image isassociated with the shorter lifetime on the lifetime scale, and asshown in histogram, the average lifetime is 3.6 ns. Moreover, we wantedto determine if there is any effect of orientation of excitation lightpolarization on the intensity and the lifetime. We found that changingthe excitation light polarization did not affect the total intensitycounts or fluorescence lifetime of ADOTA in SW deposited on silicaprotected gold mirror (see Supporting Information). This is due to the random orientation of dye molecules on glasscoverslip which leads to depolarized emission.

Bottom Line: Silica protected gold mirrors were drop-coated with a solution of silver triangular nanoprisms.The triangular nanoprisms were slowly air-dried to get silver wires that self-assembled on the gold mirrors.The lifetime of Me-ADOTA · Cl dye was significantly reduced (∼ 4 times) in the presence of SWs.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, The University of Texas at Tyler , 3900 University Boulevard, Tyler, Texas 75799, United States.

ABSTRACT
In this report we describe a preparation of silver wires (SWs) on gold mirrors and its application to surface enhanced fluorescence (SEF) using a new methodology. Silica protected gold mirrors were drop-coated with a solution of silver triangular nanoprisms. The triangular nanoprisms were slowly air-dried to get silver wires that self-assembled on the gold mirrors. Fluorescence enhancement was studied using methyl azadioxatriangulenium chloride (Me-ADOTA · Cl) dye in PVA spin-coated on a clean glass coverslip. New Plasmonic Platforms (PPs) were assembled by placing a mirror with SWs in contact with a glass coverslip spin-coated with a uniform Me-ADOTA · Cl film. It was shown that surface enhanced fluorescence is a real phenomenon, not just an enhancement of the fluorescence signal due to an accumulation of the fluorophore on rough nanostructure surfaces. The average fluorescence enhancement was found to be about 15-fold. The lifetime of Me-ADOTA · Cl dye was significantly reduced (∼ 4 times) in the presence of SWs. Moreover, fluorescence enhancement and lifetime did not show any dependence on the excitation light polarization.

Show MeSH
Related in: MedlinePlus