Preparation of Plasmonic Platforms of Silver Wires on Gold Mirrors and Their Application to Surface Enhanced Fluorescence

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.

Quantification of Material Fluorescence and Light Scattering Cross Sections Using Ratiometric Bandwidth-Varied Polarized Resonance Synchronous Spectroscopy

“…Light/matter interactions are the most fascinating phenomena in nature that have remained as central research topics since the inception of modern science. − Applications exploiting light/matter interactions encompass essentially every imaginable scientific discipline that ranges from molecular sciences to space exploration. − Depending on their optical properties in the UV–vis wavelength region, all materials can be divided into the following five categories: (1) approximate pure light absorbers with no significant light scattering and emission, (2) pure light scatterers with no significant light absorption and emission, (3) simultaneous light absorbers and scatterers with no significant photon emission, such as metal nanoparticles, − (4) simultaneous light absorbers and emitters with no significant photon scattering, all the way to (5) simultaneous light absorbers, scatterers, and emitters, including synthetic fluorescent nanoparticles and supramolecules . Many emerging functional materials, especially nanoscale photonic materials, are highly optically complicated because they can simultaneously absorb, scatter, and emit light in the same wavelength regions. − Reliable determination of the material photon extinction, absorption, scattering, and emission activities is critical for material characterizations, designs, and applications.…”

Fluorescence, Phosphorescence, and Chemiluminescence

“…A recent review by Gray et al outlines aluminum as a UV plasmonic metal, while Watson et al similarly describes the use of rhodium-based nanoparticles . Other notable surfaces include hybrid nanotubes, 2D silver gratings, high aspect ratio silver nanowires, silver wires deposited on gold mirrors and the development of nanoraspberry substrates, and a high electric field enhancing substrate composed of gold nanoparticles and aniline oligomers …”

“…A recent review by Gray et al outlines aluminum as a UV plasmonic metal, 254 while Watson et al similarly describes the use of rhodium-based nanoparticles. 255 Other notable surfaces include hybrid nanotubes, 256 2D silver gratings, 257 high aspect ratio silver nanowires, 258 silver wires deposited on gold mirrors 259 and the development of nanoraspberry substrates, 260 and a high electric field enhancing substrate composed of gold nanoparticles and aniline oligomers. 260 Virtually all reports of metal-enhanced fluorescence to date involve reports of enhanced emission spectra, whether fluorescence, phosphorescence, or indeed α-fluorescence, which appear almost identical to control samples, i.e., similar to visualizing the emission in the far-field condition.…”

Controlled surface plasmon enhanced fluorescence from 1D gold gratings via azimuth rotations

“…Accordingly, much work has focused on tailoring metal nanostructures so as to maximise the interaction between fluorophores and the electric field of the metal/dielectric plasmon, leading to the development of a range of approaches such as nanoparticles, roughened films and periodic films [8][9][10][11]. In addition to these approaches, a number of other methods using silver nanowires and particles deposited via self-assembled by controlled evaporation or by glancing angle evaporation techniques have been demonstrated to show good potential for enhanced detection of both fluorophores and auto-fluorescence from bio-molecules [12][13][14].…”