Self-Assembled Metal Nanohole Arrays with Tunable Plasmonic Properties for SERS Single-Molecule Detection (original) (raw)
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Plasmonic Sensing Characteristics of Single Nanometric Holes
Nano Letters, 2005
The optical response of isolated holes in 20 nm thin gold is probed as a function of alkanethiol CH 3 (CH 2) x SH (x ∈ 1−15) and protein adsorption using dark-field spectroscopy. We establish that the plasmon excitations of single and short-range ordered 60 nm holes exhibit similar E-field decay lengths δ ≈ 10−20 nm and that a single hole can be used to resolve the successive adsorption of a protein (biotin-BSA) and its interaction partner (neutravidin). The data confirm the localized character of the hole plasmon and demonstrate that its applicability for bio/ chemosensing is similar to that of particle plasmons.
Actuated Plasmonic Nanohole Arrays for Sensing and Optical Spectroscopy Applications
Nanoscale, 2020
Herein, we report a new approach to rapidly actuate the plasmonic characteristics of thin gold films perforated with nanohole arrays that are coupled with arrays of gold nanoparticles. The near-field interaction between the localized and propagating surface plasmon modes supported by the structure was actively modulated by changing the distance between the nanoholes and nanoparticles and varying the refractive index symmetry of the structure. This approach was applied by using a thin responsive hydrogel cushion, which swelled and collapsed by a temperature stimulus. The detailed experimental study of the changes and interplay of localized and propagating surface plasmons was complemented by numerical simulations. We demonstrate that the interrogation and excitation of the optical resonance to these modes allow the label-free SPR observation of the binding of biomolecules, and is applicable for in situ SERS studies of low molecular weight molecules attached in the gap between the nanoholes and nanoparticles. † Electronic supplementary information (ESI) available. See
Advanced Functional Materials, 2010
The discovery of EOT has stimulated a signifi cant amount of work aimed at the development of possible applications that takes full advantage of its properties. Surface plasmon resonance (SPR) chemical sensors based on PANHs platforms, for instance, provide several advantages relative to the commercial prism coupling device. [ 4,5 ] These include a smaller footprint, making them more suitable for miniaturization and integration in microfl uidics devices, and a simplifi ed optical geometry for normal transmission measurements, which enables high density multiplexing and imaging SPR. [ 6-9 ] Another area of application where PANHs can make an impact is on plasmonicenhanced photovoltaics. [ 10-12 ] The SPR of gold nanostructures allow an increase in the effi ciency of the photo-conversion process in the red-region, a range notorious poor for the current commercial solar cells. [ 13 ] Despite all these promising applications, most of the work with PANHs reported so far was realized using samples fabricated by either focused ion beam (FIB) milling or e-beam lithography. [ 14 ] These techniques allow precise tuning of the geometric parameters of the arrays. They also provide a high degree of control and sample-to-sample reproducibility of the fabricated structures. These properties make them ideal for proof-of-concepts and for systematic investigations that require fi ne control over the geometric parameters of the nanostructures. However, these nanofabrication techniques are suitable to pattern only small areas, and, as essentially serial methods, they are not practical for mass production. Hence, any possible implementation of applications based on EOT using PANHs requires a methodology for large area nanopatterning. Moreover, the distribution of PANHs on the substrate area would depend on the type of application. A large perforated area would be required for applications in photovoltaic, but microarrays of PANHs would be more suitable for biomedical applications, since it allows for multiplexing detection of bio-markers. [ 15,16 ] Several research groups have been dedicated to the development of methodologies for large area nanopatterning [ 17 ] and their application for the fabrication of PANHs. Among the
Plasmonics, 2006
Small metal nanostructures, especially gold and silver nanoparticles, are known for their interesting optical properties caused by plasmonic effects. Molecular plasmonics, a combination of these optically active nanostructures with the molecular world, opens new possibilities for bioanalytics and (bio-) nanophotonics. Isotropic or anisotropic, homogeneous or heterogeneous metal nanoparticles provide a platform for different, highly defined functional units with interesting optical properties such as plasmon waveguides or molecular beacons. Nanohole arrays in metal layers are another promising component for nanophotonics. New photonic materials were realized from combinations of single metal nanoparticles with individual nanoholes in metals. Atomic force microscopic imaging was used to determine the particle location as well as the lateral dimensions and the topography of the resulting structures. Besides ultramicroscopic characterization of the nanoarrangements, such as nanoparticles positioned in nanoholes, far-field optical methods were also applied to investigate their optical properties.
Chemosensors, 2019
Unconventional lithography (such as nanosphere lithography (NSL) and colloidal lithography (CL)) is an attractive alternative to sequential and very expensive conventional lithography for the low-cost fabrication of large-area nano-optical devices. Among these, nanohole (NH) arrays are widely studied in nanoplasmonics as transducers for sensing applications. In this work, both NSL and CL are implemented to fabricate two-dimensional distributions of gold NHs. In the case of NSL, highly ordered arrays of gold NHs distributed in a hexagonal lattice onto glass substrates were fabricated by a simple and reproducible approach based on the self-assembling of close-packed 500 nm diameter polystyrene particles at an air/water interface. After the transfer onto a solid substrate, the colloidal masks were processed to reduce the colloidal size in a controllable way. In parallel, CL was implemented with short-range ordered gold NH arrays onto glass substrates that were fabricated by electrostat...
Position Dependent Plasmonic Interaction Between a Single Nanoparticle and a Nanohole Array
Plasmonics, 2014
The interaction of surface plasmons supported on a nanohole array and a single nanoparticle affixed to an atomic force microscopy (AFM) probe was studied for optimizing gap mode enhancement of the plasmonic field. Scanning probe microscopy controlled the AFM probe position, and the location specific interaction of the single nanoparticle (SNP) probe-nanohole array surface plasmons, was measured by darkfield spectroscopy. Raster-scanned darkfield imaging of the surface plasmons on the nanohole array is demonstrated, as well as image formation from measuring the SNP interaction at various (X, Y) locations relative to the nanohole. Coupling of the nanoparticle to the nanohole array exhibited maximal coupling when the SNP resided within a nanohole, resulting in a maximum SPR wavelength shift of 17 nm and an increase in scatter intensity of 137×. This technique may be expanded to mapping nanostructure coupling across three dimensions to determine optimal coupling conditions for applications in biosensing and surface enhanced spectroscopy. This contribution presents the first empirical observations of scanning probe microscopy (SPM) controlled gap mode enhancement of more complex nanostructures, a method for positioning optimization prior to sensing applications and experimental evidence for optimal lateral SNPnanohole array positioning.
May 17-18, 2017 Istanbul (Turkey), 2017
The possibility to limit and manipulate photons at nanometer scales attracted a lot of interest for exciting applications from subwavelength in biosensors and optoelectronics devices, the sensor optical properties, however; are complex due to two resonances through propagating and localized surface plasmons. The optical properties of surface plasmons(SPs) at the resonant wavelength is depending on the geometrical nanostructure of materials. In this articles, we used different geometry of nanoholes array, 4 and 9 nanoholes array in a metallic film gold nanoparticles with different thickness (20,50,100) nm on SiO2 substrate with refractive index 1.46, we designed two different geometries; 4-holes: hole radius r1=200 nm, period p1=600 nm; and 9-holes : r2=100 nm, period p2=300 nm. Transmission and reflection spectrum have been calculated and simulated by FDTD Lumerical program. From results are observed the effect of thickness is interesting, transmission is increased at (t=20nm) for two arrays. Furthermore, the number of hole and its area has an influence on optical transmission and other parameters (E, H ,Ref) which are characteristics of design of metallic nanostructure. We can see that there is a peak value of the wavelength at 519 nm approximately to 73% strong light transmission with 4-NHA in the other hand wavelength of 519 nm transmission is 45% with 9-NHA. strong light transmission is hopeful for many applications(Biosensors devices).
The surface plasmon resonance of metal-film nanohole arrays
Solid State Communications, 2008
In this paper we investigated the enhanced transmission and surface plasmon resonance through a thin gold film with a periodic array of subwavelength nanoholes. Both freestanding gold-film nanohole arrays and gold-film nanohole arrays deposited on a gallium arsenide (GaAs) substrate are considered. Periodic arrays of nanoholes exhibit two different surface plasmon resonance features: localized waveguide resonance and the well-recognized photonic crystal resonance. The tangential electric field component E y is nonzero only in the hole region for a freestanding gold-film nanohole array, but it can exist in the hole region and in the metallic region for a gold-film nanohole array deposited on a GaAs substrate.