Extraordinary Enhancement Research Articles

Reaching the Limits of Enhancement in (Sub)Nanometer Metal Structures

Plasmonic enhancement has had remarkable success in optical coupling to the nanometer scale, enabling feats such as Raman spectroscopy with single molecule sensitivity. Here it is argued that much greater enhancements are possible in the near future by combining the gains of plasmonic resonances, directivity, subnanometer gaps, and permittivity near-zero materials. The pursuit of such extraordinary enhancements promises to bring new physics such as peering into the world of quantum optomechanics. It also promises new applications such as quantitative single molecule Raman spectroscopy and low photon number nonlinear optical switching. In addition, by pushing the limits of plasmonic enhancement, it is expected that the community will gain a greater appreciation of how physical phenomena such as nonlocality, surface scattering, and quantum tunneling each play a role in determining the ultimate performance.

Limiting clutches for “turn-on” and “turn-off” chemosensors of 1,2-bis((E)-9-anthracenyl) methyleneamino)-9,10-anthraquinone

A simple and facile synthesis of 1,2-bis((E)-9-anthracenyl)methyleneamino)-9,10-anthraquinone, BAMAAQ (L) has been achieved by the Schiff's base condensation of 1,2-diamino-9,10-anthraquinone (a primary aromatic 1,2-diamine) and anthracene-9-carboxaldehyde (an aldehyde) under reflux condition. The structure of the product obtained from spectra was characterized by FT-IR, 1H and 13C NMR and LC-MS techniques. The UV-absorption and fluorescent emission spectra were carried out for its sensing behavior towards the different metal ions for their “turn-on” and “turn-off” observations. The extraordinary enhancement and extraordinary quenching of the synthesized organic probe (L) by its chemo-sensation were observed for Cu2+ ion and Fe3+ ion, respectively. L-Cu2+ and L-Fe3+ modules were subjected for concentration-dependent (by emission spectra), pH-dependent (by absorption spectra) behaviors and the effective removal of the metal-binding probe by a chelating agent (EDTANa2) making the system attractive by their “on-off” response. FE-SEM with elemental color mapping and EDS analyses were also studied to understand their relative presence of constituted atoms for the subjected modules. The Cytotoxicity and IC50 value measurement were made for the different concentration of the ligand probe, L. And the live cell imaging techniques for the selected two modules were carried out with HepG2 cell line. The computational studies also have been carried out for the better understanding of the ligand probe (L) towards their optimized structure, Mulliken atomic charge (MPA), Natural atomic charge (NPA), surface analysis, Frontier's molecular orbitals (FMOs) and the calculation of molecular descriptors or global reactivity descriptors. The optical property of the ligand probe also investigated theoretically by NLO properties effectively by “polar” energy job.

Extraordinary Field Enhancement of TiO2 Porous Layer up to 500‐Fold

AbstractTitanium dioxide (TiO2) is known as a very important material for photocatalysts, the photoelectrode for hydrogen evolution reaction, and the porous layer of perovskite solar cells. Their properties as well as device performances such as photoconversion efficiencies are significantly enhanced if integration of TiO2 providing a large field enhancement of light is made possible. However, the field enhancement has not been revealed for TiO2 materials, and then increased device performances have not been reported either so far. Here, extraordinary field enhancement of a porous TiO2 layer, mesoscopic film, prepared by a facile wet process in conjunction with ball milling and drop casting is shown. The field enhancement is investigated with respect to the fluorescence intensity of a dye molecule and an enhancement factor (EF) of up to 500 is achieved, which corresponds to the largest EF for a semiconductor. Furthermore, EF is up to 30 000 after numerical corrections. The large EF is realized for a porous TiO2 layer composed of a specific particle size of 550 nm, which is consistent with the results of fluorescence intensity, scattering intensity, and two different theoretical calculations based on Mie scattering theory, with respect to particle size. A special advantage of the current system is the mesoscopic porous layer giving many hot spots among TiO2 particles of the specific size.

DNAzyme-embedded hyperbranched DNA dendrimers as signal amplifiers for colorimetric determination of nucleic acids.

A DNAzyme-embedded hyperbranched DNA dendrimer is used as a colorimetric signal amplifier in an ultrasensitive detection scheme for nucleic acids. The hyperbranched DNA dendrimers were constructed by single-step autonomous self-assembly of three structure-free DNA monomers. A cascade of self-assembly reactions between the first and second strands leads to the formation of linear DNA concatemers containing overhang flank fragments. The third strand, which bears a peroxidase-mimicking DNAzyme domain, serves as a bridge to trigger self-assembly between the first and second strands across the side chain direction. This results in a chain branching growth of the DNAzyme-embedded DNA dendrimer. This signal amplifier was incorporated into the streptavidin-biotin detection system which comprises an adaptor oligonucleotide and a biotinylated capture probe. The resulting platform is capable of detecting a nucleic acid target with an LOD as low as 0.8 fM. Such sensitivity is comparable if not superior to most of the reported enzyme-free (and even enzyme-assisted) signal amplification strategies. The DNA dendrimer based method is expected to provide a universal platform for extraordinary signal enhancement in detecting other nucleic acid biomarkers by altering the respective sequences of adaptor and capture probe. Graphical abstract Schematic of an assembly of a DNAzyme-embedded hyperbranched DNA dendrimer which operates as a signal amplifier for nucleic acids detection. The nanostructure is constructed by autonomous self-assembly of three DNA monomers. Colored letters represent each domain, and complementary domains aremarked by asterisk. Domain d represents the DNAzyme sequence.

Cheetah chase algorithm (CCA): a nature-inspired metaheuristic algorithm

In recent years, appreciable attention among analysts to take care of the extraordinary enhancement issues utilizing metaheuristic algorithms in the domain area of Swarm Intelligence. Many metaheuristic algorithms have been developed by inspiring various nature phenomena’s. Exploration and exploitation are distinctive capacities and confine each other, along these lines, customary calculations require numerous parameters and bunches of expenses to accomplish the adjust, and furthermore need to modify parameters for various enhancement issues. In this paper, another populace based algorithm, the Cheetah Chase Algorithm (CCA), is presented. Distinctive features of Cheetah and their characteristics has been the essential motivation for advancement of this optimization algorithm. Cheetah Chase Algorithm (CCA) has awesome capacities both in exploitation and exploration, is proposed to address these issues. To start with, CCA endeavours to locate the optimal solution in the assigned hunt territory. It at that point utilizes history data to pursue its prey. CCA can, hence, decide the situation of the worldwide ideal. CCA accomplishes solid exploitation and exploration with these highlights. Additionally, as indicated by various issues, CCA executes versatile parameter change. The self-examination and analysis of this exploration show that each CCA capacity can have different beneficial outcomes, while the execution correlation exhibits CCAs predominance over conventional metaheuristic algorithms. The proposed Cheetah Chase Algorithm is developed by the process of hunting and chasing of Cheetah to capture its prey with the parameters of high speed, velocity and greater accelerations.

Transformation of the Employees into Brand Advocates through Employer Branding

In the social media era, the extra ordinary enhancement in communication power of employee aroused the challenge for organizations how to effectively manage the benefits and risks which associated with employees thoughts sharing about their employer with external stakeholders, thus the employee’s communication power about their brand has made employee brand advocacy a buzzword in internal marketing literature. The limitation and restriction for branding is no longer for only products even organizations resorting to branding for attracting and retaining the best talent, now time changed the people more trust on the organization based on the existing employees word of mouth in recruitment which means talent attraction also dependent on employee brand advocacy. Existing literature indicates the clear gap as employee brand advocacy not studied as a pure focal concept. Hence, the present study conceptualised the employer branding relationship with employee brand advocacy.

Extraordinary Enhancement of Quadrupolar Transitions Using Nanostructured Graphene

Surface plasmons supported by metallic nanostructures interact strongly with light and confine it into subwavelength volumes, thus forcing the corresponding electric field to vary within nanoscale distances. This results in exceedingly large field gradients that can be exploited to enhance the quadrupolar transitions of quantum emitters located in the vicinity of the nanostructure. Graphene nanostructures are ideally suited for this task, since their plasmons can confine light into substantially smaller volumes than equivalent excitations sustained by conventional plasmonic nanostructures. Furthermore, in addition to their geometric tunability, graphene plasmons can also be efficiently tuned by controlling the doping level of the nanostructure, which can be accomplished either chemically or electrostatically. Here, we provide a detailed investigation of the enhancement of the field gradient in the vicinity of different graphene nanostructures. Using rigorous solutions of Maxwell’s equations, as well as an...

Extraordinary Enhancement of UV Absorption in TiO2 Nanoparticles Enabled by Low-Oxidized Graphene Nanodots

Titanium oxide (TiO2) exhibits intrinsically strong absorption of ultraviolet (UV) light, which has been utilized in a variety of applications, such as environmental purification/sterilization, hea...

Plasmonic Heterodimers with Binding Site-Dependent Hot Spot for Surface-Enhanced Raman Scattering.

A novel plasmonic heterodimer nanostructure with a controllable self-assembled hot spot is fabricated by the conjugation of individual Au@Ag core-shell nanocubes (Au@Ag NCs) and varisized gold nanospheres (GNSs) via the biotin-streptavidin interaction from the ensemble to the single-assembly level. Due to their featured configurations, three types of heterogeneous nanostructures referred to as Vertice, Vicinity, and Middle are proposed and a single hot spot forms between the nanocube and nanosphere, which exhibits distinct diversity in surface plasmon resonance effect. Herein, the calculated surface-enhanced Raman scattering enhancement factors of the three types of heterodimers show a narrow distribution and can be tuned in orders of magnitude by controlling the size of GNSs onto individual Au@Ag NCs. Particularly, the Vertice heterodimer with unique configuration can provide extraordinary enhancement of the electric field for the single hot spot region due to the collaborative interaction of lightning rod effect and interparticle plasmon coupling effect. This established relationship between the architecture and the corresponding optical properties of the heterodimers provides the basis for creating controllable platforms which can be exploited in the applications of plasmonic devices, electronics, and biodetection.

Resonance enhancement of Faraday rotation in double-periodic gyromagnetic layers analyzed by the method of integral functionals

Extraordinary enhancement of the Faraday rotation (over 1000 times) for a perfect electric conductor (PEC)-like layer with square-shaped apertures filled with yttrium iron garnet (YIG) and its smaller enhancement (17 times) for a YIG layer perforated with square-shaped air apertures are revealed at the grating-mode resonance frequencies. At the same time, the periodic perforation of a PEC-like layer with C-shaped apertures filled with YIG does not influence the Faraday effect. For our theoretical study, we develop the full-wave solution for the three-dimensional (3D) problem of the plane wave scattering from a double-periodic gyromagnetic layer obtained by the method of integral functionals. The method is based on the 3D volume integral equations for the electric and magnetic polarization currents on the periodic layer.

Nanoplasmonic Alloy of Au/Ag Nanocomposites on Paper Substrate for Biosensing Applications.

Plasmonic alloy has attracted much interest in tailoring localized surface plasmon resonance (LSPR) for recent biosensing techniques. In particular, paper-based plasmonic substrates allow capillary-driven lateral flow as well as three-dimensional metal nanostructures, and therefore they become actively transferred to LSPR-based biosensing such as surface-enhanced Raman spectroscopy (SERS) or metal-enhanced fluorescence (MEF). However, employing plasmonic alloy nanoislands on heat-sensitive substrate is still challenging, which significantly inhibits broad-range tailoring of the plasmon resonance wavelength (PRW) for superior sensitivity. Here we report paper-based plasmonic substrate with plasmonic alloy of Au/Ag nanocomposites for highly sensitive MEF and SERS biosensing applications. The nanofabrication procedures include concurrent deposition of Au and Ag below 100 °C without any damage on cellulose fibers. The Au/Ag nanocomposites feature nanoplasmonic alloy with single plasmon peak as well as broad-range tunability of PRW by composition control. This paper-based plasmonic alloy substrate enables about twofold enhancement of fluorescence signals and selective MEF after paper chromatography. The experimental results clearly demonstrate extraordinary enhancement in SERS signals for picomolar detection of folic acid as a cancer biomarker. This new method provides huge opportunities for fabricating plasmonic alloy on heat-sensitive substrate and biosensing applications.

Extraordinary Light-Trapping Enhancement in Silicon Solar Cell Patterned with Graded Photonic Super-Crystals

Light-trapping enhancement in newly discovered graded photonic super-crystals (GPSCs) with dual periodicity and dual basis is herein explored for the first time. Broadband, wide-incident-angle, and polarization-independent light-trapping enhancement was achieved in silicon solar cells patterned with these GPSCs. These super-crystals were designed by multi-beam interference, rendering them flexible and efficient. The optical response of the patterned silicon solar cell retained Bloch-mode resonance; however, light absorption was greatly enhanced in broadband wavelengths due to the graded, complex unit super-cell nanostructures, leading to the overlap of Bloch-mode resonances. The broadband, wide-angle light coupling and trapping enhancement mechanism are understood to be due to the spatial variance of the index of refraction, and this spatial variance is due to the varying filling fraction, the dual basis, and the varying lattice constants in different directions.

Fast vertical mode expansion method for the simulation of extraordinary terahertz field enhancement in an annular nanogap

This paper is concerned with electromagnetic wave scattering of an annular nanogap in the terahertz regime. We present an efficient vertical mode expansion method (VMEM) to solve the scattering problem, and study the extraordinary optical transmission and field enhancement for the nanostructure with various configurations. The VMEM expands the electromagnetic field in and outside the nanogap along the invariant direction by the one-dimensional modes, where the expansion coefficients satisfy scalar two-dimensional Helmholtz equations on the cross-sectional plane. The continuity conditions of electromagnetic fields on the vertical boundaries of neighboring regions are then employed to establish the linear system for the unknown coefficients. Based on the numerical simulations, we investigate the field enhancement in the nanogap. In particular, we investigate the nanostructure with a series of gap sizes and push the gap width limit to 1 nm in the numerical simulation. The normal and oblique incidence cases and the transverse electric (TE) and transverse magnetic (TM) polarization cases are considered.

Extraordinary toughness enhancement of poly(lactic acid) by incorporating very low loadings of noncovalent functionalized graphene-oxide via masterbatch-based melt blending

In this work, poly(lactic acid) (PLA)/graphene oxide nanocomposites were prepared by pre-incorporating noncovalently functionalized GO (f-GO) with didodecyldimethylammonium bromide (DDAB) into PLA via solvent-mixing and subsequently masterbatch-based melt blending. The introduction of only 0.2 wt% f-GO into PLA achieved an extraordinarily 26.6-fold increase in elongation-at-break relative to PLA without sacrificing strengths. Such an extraordinary improvement in toughness was attributed to the excellent exfoliation of GO sheets and appropriate level of interfacial adhesion between PLA and modified GO nanosheets, thus facilitating the yielding of the matrix.

Broadband enhancement of dielectric light trapping nanostructure used in ultra-thin solar cells

A dielectric fishnet nanostructure is designed to increase the light trapping capability of ultra-thin solar cells. The complex performance of ultra-thin cells such as the optical response and electrical response are fully quantified in simulation through a complete optoelectronic investigation. The results show that the optimized light trapping nanostructure can enhances the electromagnetic resonance in active layer then lead to extraordinary enhancement of both absorption and light-conversion capabilities in the solar cell. The short-circuit current density increases by 49.46% from 9.40 mA/cm2 to 14.05 mA/cm2 and light-conversion efficiency increases by 51.84% from 9.51% to 14.44% compared to the benchmark, a solar cell with an ITO-GaAs-Ag structure.

Evidence for lattice softening of the Fe-Ga magnetostrictive alloy: Stress-induced local martensites

The over tenfold magnetostriction enhancement by soluting nonmagnetic Ga into body centered cubic (BCC) Fe has been ascribed to crystal lattice softening, which indicates that the Fe-Ga solid solution lies in the crossover of martensitic transformation. Identifying the martensitic phase then becomes essential. Here we report the stress-induced local six-layer modulated monoclinic (6M) martensites in a Fe79Ga21 alloy solution-treated at 1373K. Although X-ray diffraction (XRD) and magnetic measurements reveal that the bulk sample exhibits BCC average structure, the transmission electronic microscopy (TEM) characterizations however show that the mechanically grinded foil sample contains local 6M phase. First principal calculations suggest that low formation energy barrier between the ordered D03 and the 6M phases are responsible for the stress-induced structural transformation. Our work provides evidence for the lattice softening of Fe-Ga solid solution, adding important insight into understanding the origin of its extraordinary magnetostriction enhancement.

Cavity Antiresonance Spectroscopy of Dipole Coupled Subradiant Arrays.

An array of N closely spaced dipole coupled quantum emitters exhibits super- and subradiance with characteristic tailorable spatial radiation patterns. Optimizing the emitter geometry and distance with respect to the spatial profile of a near resonant optical cavity mode allows us to increase the ratio between light scattering into the cavity mode and free space emission by several orders of magnitude. This leads to distinct scaling of the collective coherent emitter-field coupling vs the free space decay as a function of the emitter number. In particular, for subradiant states, the effective cooperativity increases much faster than the typical linear ∝N scaling for independent emitters. This extraordinary collective enhancement is manifested both in the amplitude and the phase profile of narrow collective antiresonances appearing at the cavity output port in transmission spectroscopy.

Rhamnolipids: Highly Compatible Surfactants for the Enzymatic Hydrolysis of Waste Frying Oils in Microemulsion Systems

In this work, we explore a novel application for rhamnolipid (RHL) biosurfactants as emulsifiers for water-in-oil microemulsions, focused on enhancing the state of the art of oil hydrolysis in emulsion systems. We show that RHL can form microemulsions with a stability comparable to that provided by the widely used synthetic surfactant bis(2-ethylhexil) sulfosuccinate (AOT). In addition, we test RHL-based microemulsions as reaction media for the enzymatic hydrolysis of waste frying oil (WFO) to produce added-value products. To this aim, we analyze the influence on the hydrolysis degree of several key parameters, such as the amount of cosurfactant, the water/surfactant molar ratio, and the oil volume fraction in the organic phase. Remarkably, under the same conditions RHL leads to a hydrolysis degree 35% higher than that of AOT. Furthermore, RHL also increases the average hydrolysis rate and shows an extraordinary enhancement of the enzyme stability in comparison to that of AOT. Our results demonstrate that...

Metal–Dielectric Hybrid Dimer Nanoantenna: Coupling between Surface Plasmons and Dielectric Resonances for Fluorescence Enhancement

Dimers made of noble metal particles possess extraordinary field enhancements but suffer from large dissipation, whereas low-loss dielectric dimers are limited by relatively weak optical confinement. Hybrid systems could take advantages from both worlds. In this contribution, we study the mode coupling in a hybrid dimer with rigorous dipole–dipole interaction theory and explore its potential in fluorescence enhancement. We first discovered that the direct coupling between metal surface–plasmon resonance and dielectric electric–dipole mode creates a hybridized mode due to the strong electric–electric dipole–dipole interaction between the constituent nanoparticles, whereas the dielectric magnetic–dipole mode can only indirectly couple to the plasmons on the basis of the induced electric–magnetic dipole–dipole interaction. When an electric/magnetic quantum emitter couples to the hybrid dimer, the emitter selectively excites the electric/magnetic (magnetic/electric) resonant modes of the dimer for emitter ori...

Back Cover: Formation Mechanism of NF4+ Salts and Extraordinary Enhancement of the Oxidizing Power of Fluorine by Strong Lewis Acids (Angew. Chem. Int. Ed. 27/2017)

Back Cover: Formation Mechanism of NF₄⁺ Salts and Extraordinary Enhancement of the Oxidizing Power of Fluorine by Strong Lewis Acids (Angew. Chem. Int. Ed. 27/2017)