Nanomaterials

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12 pages, 6477 KiB

Open AccessArticle

Spatially-Localized Functionalization on Nanostructured Surfaces for Enhanced Plasmonic Sensing Efficacy

by Jean-François Bryche, Marlo Vega, Agnès Tempez, Thibault Brulé, Thomas Carlier, Julien Moreau, Marc Chaigneau, Paul G. Charette and Michael Canva

Nanomaterials 2022, 12(20), 3586; https://doi.org/10.3390/nano12203586 - 13 Oct 2022

Viewed by 1514

Abstract

This work demonstrates the enhancement in plasmonic sensing efficacy resulting from spatially-localized functionalization on nanostructured surfaces, whereby probe molecules are concentrated in areas of high field concentration. Comparison between SERS measurements on nanostructured surfaces (arrays of nanodisks 110 and 220 nm in diameter) [...] Read more.

This work demonstrates the enhancement in plasmonic sensing efficacy resulting from spatially-localized functionalization on nanostructured surfaces, whereby probe molecules are concentrated in areas of high field concentration. Comparison between SERS measurements on nanostructured surfaces (arrays of nanodisks 110 and 220 nm in diameter) with homogeneous and spatially-localized functionalization with thiophenol demonstrates that the Raman signal originates mainly from areas with high field concentration. TERS measurements with 10 nm spatial resolution confirm the field distribution profiles predicted by the numerical modeling. Though this enhancement in plasmonic sensing efficacy is demonstrated with SERS, results apply equally well to any type of optical/plasmonic sensing on functionalized surfaces with nanostructuring. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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20 pages, 5180 KiB

Open AccessArticle

Phyto-Capped Ag Nanoparticles: Green Synthesis, Characterization, and Catalytic and Antioxidant Activities

by Mohamed G. M. Kordy, Mohammed Abdel-Gabbar, Hanan A. Soliman, Ghadah Aljohani, Mohammad BinSabt, Inas A. Ahmed and Mohamed Shaban

Nanomaterials 2022, 12(3), 373; https://doi.org/10.3390/nano12030373 - 24 Jan 2022

Cited by 24 | Viewed by 4869

Abstract

Using a simple approach, silver nanoparticles (Ag NPs) were synthesized from green coffee bean extract. The optical color change from yellowish to reddish-brown of the green-produced Ag NPs was initially observed, which was confirmed by the UV-Visible spectrophotometer’s surface plasmonic resonance (SPR) bands [...] Read more.

Using a simple approach, silver nanoparticles (Ag NPs) were synthesized from green coffee bean extract. The optical color change from yellowish to reddish-brown of the green-produced Ag NPs was initially observed, which was confirmed by the UV-Visible spectrophotometer’s surface plasmonic resonance (SPR) bands at 329 and 425 nm. The functional groups of green coffee-capped Ag NPs (GC-capped Ag NPs) were studied using a Fourier transform infrared spectrometer, revealing that Ag NPs had been capped by phytochemicals, resulting in excellent stability, and preventing nanoparticle aggregation. The presence of elemental silver is confirmed by energy dispersive X-ray analysis. In addition to the measurement of the zeta potential of the prepared GC-capped Ag NPs, the size distribution is evaluated by the dynamic light scattering. Depending on the nano-morphological study, the particle diameter of Ag NPs is 8.6 ± 3.5 nm, while the particle size of GC-capped Ag NPs is 29.9 ± 4.3 nm, implying the presence of well-dispersed nanospheres with an average capsulation layer of thickness 10.7 nm. The phyto-capped Ag NPs were found to be crystalline, having a face-centered cubic (FCC) lattice structure and Ag crystallite size of ~7.2 nm, according to the XRD crystallographic analysis. The catalytic performance of phyto-capped Ag NPs in the removal of methylene blue dye by sodium borohydride (NaBH₄) was investigated for 12 min to reach a degradation efficiency of approximately 96%. The scavenging activities of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radicals are also examined in comparison to previously reported Ag-based nano-catalysts, demonstrating a remarkable IC₅₀ of 26.88 µg/mL, which is the first time it has been recorded. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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13 pages, 2906 KiB

Open AccessArticle

Combination of Capped Gold Nanoslit Array and Electrochemistry for Sensitive Aqueous Mercuric Ions Detection

by Cheng-Chuan Chen, Shu-Cheng Lo and Pei-Kuen Wei

Nanomaterials 2022, 12(1), 88; https://doi.org/10.3390/nano12010088 - 29 Dec 2021

Cited by 4 | Viewed by 1466

Abstract

Label-free surface plasmon resonance (SPR) detection of mercuric ions in various aqueous solutions, using capped gold nanoslit arrays combined with electrochemical (EC) sensing technique, is demonstrated. The nanoslit arrays are fabricated on flexible cyclo-olefin polymer substrates by a nanoimprinting lithography method. The EC [...] Read more.

Label-free surface plasmon resonance (SPR) detection of mercuric ions in various aqueous solutions, using capped gold nanoslit arrays combined with electrochemical (EC) sensing technique, is demonstrated. The nanoslit arrays are fabricated on flexible cyclo-olefin polymer substrates by a nanoimprinting lithography method. The EC and SPR signals for the investigation of current responses and transmission SPR spectra are simultaneously measured during metal ions electrodeposition. Glycerol–water solution is studied to evaluate the resonant peak wavelength sensitivity (480.3 nm RIU⁻¹) with a FOM of 40.0 RIU⁻¹ and the obtained intensity sensitivity is 1819.9%. The ferrocyanide/ferricyanide redox couple performs the diffusion controlled electrochemical processes (R² = 0.99). By investigating the SPR intensity changes and wavelength shifts of various mercuric ion concentrations, the optical properties are evaluated under chronoamperometric conditions. The sensors are evaluated in the detection range between 100 μM and 10 nM with a detection limit of 1 μM. The time dependence of SPR signals and the selectivity of 10 μM Hg²⁺ in the presence of 10 μM interfering metal ion species from Ca²⁺, Co²⁺, Ni²⁺, Na⁺, Cu²⁺, Pb^{2 +} and Mn²⁺ are determined. The capped gold nanoslit arrays show the selectivity of Hg²⁺ and the EC sensing method is effectively utilized to aqueous Hg²⁺ detection. This study provides a label-free detection technique of mercuric ions and this developed system is potentially applicable to detecting chemicals and biomolecules. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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14 pages, 3695 KiB

Open AccessArticle

Robust LSPR Sensing Using Thermally Embedded Au Nanoparticles in Glass Substrates

by Nuno M. Figueiredo, Ricardo Serra and Albano Cavaleiro

Nanomaterials 2021, 11(6), 1592; https://doi.org/10.3390/nano11061592 - 17 Jun 2021

Cited by 8 | Viewed by 2528

Abstract

The poor adhesion and chemical and thermal stability of plasmonic nanostructures deposited on solid surfaces are a hindrance to the longevity and long-term development of robust localized surface plasmon resonance (LSPR)-based systems. In this paper, we have deposited gold (Au) nanolayers with thicknesses [...] Read more.

The poor adhesion and chemical and thermal stability of plasmonic nanostructures deposited on solid surfaces are a hindrance to the longevity and long-term development of robust localized surface plasmon resonance (LSPR)-based systems. In this paper, we have deposited gold (Au) nanolayers with thicknesses above the percolation limit over glass substrates and have used a thermal annealing treatment at a temperature above the substrate’s glass transition temperature to promote the dewetting, recrystallization, and thermal embedding of Au nanoparticles (NPs). Due to the partial embedding in glass, the NPs were strongly adherent to the surface of the substrate and were able to resist to the commonly used cleaning procedures and mechanical adhesion tests alike. The reflectivity of the embedded nanostructures was studied and shown to be strongly dependent on the NP size/shape distributions and on the degree of NP embedding. Strong optical scattering bands with increasing width and redshifted LSPR peak position were observed with the Au content. Refractive index sensitivity (RIS) values between 150 and 360 nm/RIU (concerning LSPR band edge shift) or between 32 and 72 nm/RIU (concerning LSPR peak position shift) were obtained for the samples having narrower LSPR extinction bands. These robust LSPR sensors can be used following a simple excitation/detection scheme consisting of a reflectance measurement at a fixed angle and wavelength. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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12 pages, 2166 KiB

Open AccessEditor’s ChoiceArticle

An Inverted Honeycomb Plasmonic Lattice as an Efficient Refractive Index Sensor

by Javier Rodríguez-Álvarez, Lorenzo Gnoatto, Marc Martínez-Castells, Albert Guerrero, Xavier Borrisé, Arantxa Fraile Rodríguez, Xavier Batlle and Amílcar Labarta

Nanomaterials 2021, 11(5), 1217; https://doi.org/10.3390/nano11051217 - 04 May 2021

Cited by 1 | Viewed by 2492

Abstract

We present an efficient refractive index sensor consisting of a heterostructure that contains an Au inverted honeycomb lattice as a main sensing element. Our design aims at maximizing the out-of-plane near-field distributions of the collective modes of the lattice mapping the sensor surroundings. [...] Read more.

We present an efficient refractive index sensor consisting of a heterostructure that contains an Au inverted honeycomb lattice as a main sensing element. Our design aims at maximizing the out-of-plane near-field distributions of the collective modes of the lattice mapping the sensor surroundings. These modes are further enhanced by a patterned SiO₂ layer with the same inverted honeycomb lattice, an SiO₂ spacer, and an Au mirror underneath the Au sensing layer that contribute to achieving a high performance. The optical response of the heterostructure was studied by numerical simulation. The results corresponding to one of the collective modes showed high sensitivity values ranging from 99 to 395 nm/RIU for relatively thin layers of test materials within 50 and 200 nm. In addition, the figure of merit of the sensor detecting slight changes of the refractive index of a water medium at a fixed wavelength was as high as 199 RIU⁻¹. As an experimental proof of concept, the heterostructure was manufactured by a simple method based on electron beam lithography and the measured optical response reproduces the simulations. This work paves the way for improving both the sensitivity of plasmonic sensors and the signal of some enhanced surface spectroscopies. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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10 pages, 2416 KiB

Open AccessCommunication

SERS Biosensor Based on Engineered 2D-Aperiodic Nanostructure for In-Situ Detection of Viable Brucella Bacterium in Complex Matrix

by Massimo Rippa, Riccardo Castagna, Domenico Sagnelli, Ambra Vestri, Giorgia Borriello, Giovanna Fusco, Jun Zhou and Lucia Petti

Nanomaterials 2021, 11(4), 886; https://doi.org/10.3390/nano11040886 - 31 Mar 2021

Cited by 12 | Viewed by 2301

Abstract

Brucella is a foodborne pathogen globally affecting both the economy and healthcare. Surface Enhanced Raman Spectroscopy (SERS) nano-biosensing can be a promising strategy for its detection. We combined high-performance quasi-crystal patterned nanocavities for Raman enhancement with the use of covalently immobilized Tbilisi bacteriophages [...] Read more.

Brucella is a foodborne pathogen globally affecting both the economy and healthcare. Surface Enhanced Raman Spectroscopy (SERS) nano-biosensing can be a promising strategy for its detection. We combined high-performance quasi-crystal patterned nanocavities for Raman enhancement with the use of covalently immobilized Tbilisi bacteriophages as high-performing bio-receptors. We coupled our efficient SERS nano-biosensor to a Raman system to develop an on-field phage-based bio-sensing platform capable of monitoring the target bacteria. The developed biosensor allowed us to identify Brucella abortus in milk by our portable SERS device. Upon bacterial capture from samples (10⁴ cells), a signal related to the pathogen recognition was observed, proving the concrete applicability of our system for on-site and in-food detection. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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10 pages, 4777 KiB

Open AccessArticle

Tunable Split-Disk Metamaterial Absorber for Sensing Application

by Yusheng Zhang, Peng Lin and Yu-Sheng Lin

Nanomaterials 2021, 11(3), 598; https://doi.org/10.3390/nano11030598 - 27 Feb 2021

Cited by 49 | Viewed by 3386

Abstract

We present four designs of tunable split-disk metamaterial (SDM) absorbers. They consist of a bottom gold (Au) mirror layer anchored on Si substrate and a suspended-top SDM nanostructure with one, two, three, and four splits named SDM-1, SDM-2, SDM-3, and SDM-4, respectively. By [...] Read more.

We present four designs of tunable split-disk metamaterial (SDM) absorbers. They consist of a bottom gold (Au) mirror layer anchored on Si substrate and a suspended-top SDM nanostructure with one, two, three, and four splits named SDM-1, SDM-2, SDM-3, and SDM-4, respectively. By tailoring the geometrical configurations, the four SDMs exhibit different tunable absorption resonances spanning from 1.5 µm to 5.0 µm wavelength range. The resonances of absorption spectra can be tuned in the range of 320 nm, and the absorption intensities become lower by increasing the gaps of the air insulator layer. To increase the sensitivity of the proposed devices, SDMs exhibit high sensitivities of 3312 nm/RIU (refractive index unit, RIU), 3362 nm/RIU, 3342 nm/RIU, and 3567 nm/RIU for SDM-1, SDM-2, SDM-3, and SDM-4, respectively. The highest correlation coefficient is 0.99999. This study paves the way to the possibility of optical gas sensors and biosensors with high sensitivity. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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13 pages, 3067 KiB

Open AccessArticle

Highly Efficient Light Absorption of Monolayer Graphene by Quasi-Bound State in the Continuum

by Tian Sang, Sina Abedini Dereshgi, Wisnu Hadibrata, Ibrahim Tanriover and Koray Aydin

Nanomaterials 2021, 11(2), 484; https://doi.org/10.3390/nano11020484 - 14 Feb 2021

Cited by 48 | Viewed by 3846

Abstract

Graphene is an ideal ultrathin material for various optoelectronic devices, but poor light–graphene interaction limits its further applications particularly in the visible (Vis) to near-infrared (NIR) region. Despite tremendous efforts to improve light absorption in graphene, achieving highly efficient light absorption of monolayer [...] Read more.

Graphene is an ideal ultrathin material for various optoelectronic devices, but poor light–graphene interaction limits its further applications particularly in the visible (Vis) to near-infrared (NIR) region. Despite tremendous efforts to improve light absorption in graphene, achieving highly efficient light absorption of monolayer graphene within a comparatively simple architecture is still urgently needed. Here, we demonstrate the interesting attribute of bound state in the continuum (BIC) for highly efficient light absorption of graphene by using a simple Si-based photonic crystal slab (PCS) with a slit. Near-perfect absorption of monolayer graphene can be realized due to high confinement of light and near-field enhancement in the Si-based PCS, where BIC turns into quasi-BIC due to the symmetry-breaking of the structure. Theoretical analysis based on the coupled mode theory (CMT) is proposed to evaluate the absorption performances of monolayer graphene integrated with the symmetry-broken PCS, which indicates that high absorption of graphene is feasible at critical coupling based on the destructive interference of transmission light. Moreover, the absorption spectra of the monolayer graphene are stable to the variations of the structural parameters, and the angular tolerances of classical incidence can be effectively improved via full conical incidence. By using the full conical incidence, the angular bandwidths for the peak absorptivity and for the central wavelength of graphene absorption can be enhanced more than five times and 2.92 times, respectively. When the Si-based PCS with graphene is used in refractive index sensors, excellent sensing performances with sensitivity of 604 nm/RIU and figure of merit (FoM) of 151 can be achieved. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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10 pages, 3038 KiB

Open AccessArticle

Plasmonic Gold Nanohole Arrays for Surface-Enhanced Sum Frequency Generation Detection

by Wei Guo, Bowen Liu, Yuhan He, Enming You, Yongyan Zhang, Shengchao Huang, Jingjing Wang and Zhaohui Wang

Nanomaterials 2020, 10(12), 2557; https://doi.org/10.3390/nano10122557 - 19 Dec 2020

Cited by 7 | Viewed by 3163

Abstract

Nobel metal nanohole arrays have been used extensively in chemical and biological systems because of their fascinating optical properties. Gold nanohole arrays (Au NHAs) were prepared as surface plasmon polariton (SPP) generators for the surface-enhanced sum-frequency generation (SFG) detection of 4-Mercaptobenzonitrile (4-MBN). The [...] Read more.

Nobel metal nanohole arrays have been used extensively in chemical and biological systems because of their fascinating optical properties. Gold nanohole arrays (Au NHAs) were prepared as surface plasmon polariton (SPP) generators for the surface-enhanced sum-frequency generation (SFG) detection of 4-Mercaptobenzonitrile (4-MBN). The angle-resolved reflectance spectra revealed that the Au NHAs have three angle-dependent SPP modes and two non-dispersive localized surface plasmon resonance (LSPR) modes under different structural orientation angles (sample surface orientation). An enhancement factor of ~30 was achieved when the SPP and LSPR modes of the Au NHAs were tuned to match the incident visible (VIS) and output SFG, respectively. This multi-mode matching strategy provided flexible controls and selective spectral windows for surface-enhanced measurements, and was especially useful in nonlinear spectroscopy where more than one light beam was involved. The structural orientation- and power-dependent performance demonstrated the potential of plasmonic NHAs in SFG and other nonlinear sensing applications, and provided a promising surface molecular analysis development platform. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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14 pages, 3216 KiB

Open AccessArticle

Plasmonic-Layered InAs/InGaAs Quantum-Dots-in-a-Well Pixel Detector for Spectral-Shaping and Photocurrent Enhancement

by Jehwan Hwang, Zahyun Ku, Jiyeon Jeon, Yeongho Kim, Jun Oh Kim, Deok-Kee Kim, Augustine Urbas, Eun Kyu Kim and Sang Jun Lee

Nanomaterials 2020, 10(9), 1827; https://doi.org/10.3390/nano10091827 - 13 Sep 2020

Cited by 4 | Viewed by 2899

Abstract

The algorithmic spectrometry as an alternative to traditional approaches has the potential to become the next generation of infrared (IR) spectral sensing technology, which is free of physical optical filters, and only a very small number of data are required from the IR [...] Read more.

The algorithmic spectrometry as an alternative to traditional approaches has the potential to become the next generation of infrared (IR) spectral sensing technology, which is free of physical optical filters, and only a very small number of data are required from the IR detector. A key requirement is that the detector spectral responses must be engineered to create an optimal basis that efficiently synthesizes spectral information. Light manipulation through metal perforated with a two-dimensional square array of subwavelength holes provides remarkable opportunities to harness the detector response in a way that is incorporated into the detector. Instead of previous experimental efforts mainly focusing on the change over the resonance wavelength by tuning the geometrical parameters of the plasmonic layer, we experimentally and numerically demonstrate the capability for the control over the shape of bias-tunable response spectra using a fixed plasmonic structure as well as the detector sensitivity improvement, which is enabled by the anisotropic dielectric constants of the quantum dots-in-a-well (DWELL) absorber and the presence of electric field along the growth direction. Our work will pave the way for the development of an intelligent IR detector, which is capable of direct viewing of spectral information without utilizing any intervening the spectral filters. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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13 pages, 2516 KiB

Open AccessArticle

Study on Electron-Induced Surface Plasmon Coupling with Quantum Well Using a Perturbation Method

by Yifan Chen, Yulong Feng, Zhizhong Chen, Fei Jiao, Jinglin Zhan, Yiyong Chen, Jingxin Nie, Zuojian Pan, Xiangning Kang, Shunfeng Li, Qi Wang, Shulin Zhang, Guoyi Zhang and Bo Shen

Nanomaterials 2020, 10(5), 913; https://doi.org/10.3390/nano10050913 - 09 May 2020

Cited by 5 | Viewed by 2539

Abstract

Ag nanoparticles (NPs) are filled in a photonic crystal (PhC) hole array on green light emitting diodes (LEDs). The localized surface plasmon (LSP)–quantum well (QW) coupling effect is studied by measuring the cathodoluminescence (CL) spectra impinging at the specific spots on the Ag [...] Read more.

Ag nanoparticles (NPs) are filled in a photonic crystal (PhC) hole array on green light emitting diodes (LEDs). The localized surface plasmon (LSP)–quantum well (QW) coupling effect is studied by measuring the cathodoluminescence (CL) spectra impinging at the specific spots on the Ag NPs. Twenty-six percent and fifty-two percent enhancements of the CL intensities are obtained at the center and edge of the Ag NP, respectively, compared to the result that the electron-beam (e-beam) excites the QW directly. To illustrate the coupling process of the three-body system of e-beam–LSP–QW, a perturbation theory combining a three-dimensional (3D) finite difference time domain (FDTD) simulation is put forward. The effects of the polarization orientation of the dipole and the field symmetry of the LSP on the LSP–QW coupling are also discussed. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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Review

Jump to: Research

34 pages, 4360 KiB

Open AccessReview

Optical Interconnects Finally Seeing the Light in Silicon Photonics: Past the Hype

by Hosam Mekawey, Mohamed Elsayed, Yehea Ismail and Mohamed A. Swillam

Nanomaterials 2022, 12(3), 485; https://doi.org/10.3390/nano12030485 - 29 Jan 2022

Cited by 20 | Viewed by 6009

Abstract

Electrical interconnects are becoming a bottleneck in the way towards meeting future performance requirements of integrated circuits. Moore’s law, which observes the doubling of the number of transistors in integrated circuits every couple of years, can no longer be maintained due to reaching [...] Read more.

Electrical interconnects are becoming a bottleneck in the way towards meeting future performance requirements of integrated circuits. Moore’s law, which observes the doubling of the number of transistors in integrated circuits every couple of years, can no longer be maintained due to reaching a physical barrier for scaling down the transistor’s size lower than 5 nm. Heading towards multi-core and many-core chips, to mitigate such a barrier and maintain Moore’s law in the future, is the solution being pursued today. However, such distributed nature requires a large interconnect network that is found to consume more than 80% of the microprocessor power. Optical interconnects represent one of the viable future alternatives that can resolve many of the challenges faced by electrical interconnects. However, reaching a maturity level in optical interconnects that would allow for the transition from electrical to optical interconnects for intra-chip and inter-chip communication is still facing several challenges. A review study is required to compare the recent developments in the optical interconnects with the performance requirements needed to reach the required maturity level for the transition to happen. This review paper dissects the optical interconnect system into its components and explains the foundational concepts behind the various passive and active components along with the performance metrics. The performance of different types of on-chip lasers, grating and edge couplers, modulators, and photodetectors are compared. The potential of a slot waveguide is investigated as a new foundation since it allows for guiding and confining light into low index regions of a few tens of nanometers in cross-section. Additionally, it can be tuned to optimize transmissions over 90° bends. Hence, high-density opto-electronic integrated circuits with optical interconnects reaching the dimensions of their electrical counterparts are becoming a possibility. The latest complete optical interconnect systems realized so far are reviewed as well. Full article

(This article belongs to the Special Issue Plasmonic Nanostructures and Their Applications)

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