Interparticle Gap Geometry Effects on Chiroptical Properties of Plasmonic Nanoparticle Assemblies

2021 ◽  
Author(s):  
Feng Li ◽  
Skandan Chandrasekar ◽  
Aftab Ahmed ◽  
Anna Klinkova
Keyword(s):  
Rational Design ◽  
Incident Light ◽  
Structure Property ◽  
Large Area ◽  
Chiroptical Properties ◽  
Plasmonic Nanoparticle ◽  
Face To Face ◽  
Nanoparticle Assemblies ◽  
Systematic Understanding ◽  
Difference Time

Abstract Chiral linear assemblies of plasmonic nanoparticles with chiral optical activity often show low asymmetry factors. Systematic understanding of the structure-property relationship in these systems must be improved to facilitate rational design of their chiroptical response. Here we study the effect of large-area interparticle gaps in chiral linear nanoparticle assemblies on their chiroptical properties using a tetrahelix structure formed by a linear face-to-face assembly of nanoscale Au tetrahedra. Using finite-difference time-domain and finite element methods, we performed in-depth evaluation of the extinction spectra and electric field distribution in the tetrahelix structure and its dependence on various geometric parameters. The reported structure supports various plasmonic modes, one of which shows a strong incident light handedness selectivity that is associated with large face-to-face junctions. This works highlights the importance of gap engineering in chiral plasmonic assemblies to achieve g-factors greater than 1 and produce structures with a handedness-selective optical response.

scholarly journals Optical properties of silver nanocube surfaces obtained by silane immobilization

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Virginia Merk ◽  
Alexander Nerz ◽  
Sebastian Fredrich ◽  
Ulrich Gernert ◽  
Sören Selve ◽  
...  
Keyword(s):  
Electric Fields ◽  
Finite Difference Time Domain ◽  
Simple Approach ◽  
Nano Particle ◽  
Face To Face ◽  
On Demand ◽  
Silver Nanocubes ◽  
Enhancement Factors ◽  
Glass Surfaces ◽  
Difference Time

AbstractSilver nanocubes were synthesized by the polyol method and immobilized on a surface in a simple approach using an aminopropyltriethoxysilane (APTES). The optical and structural properties of the polyvinylpyrrolidone (PVP) stabilized nanocubes were investigated in solution and on glass surfaces. The SERS enhancement factors at two excitation wavelengths for crystal violet were compared with electric fields arising in different nano¬particle configurations using finite-difference time-domain simulations. They are in agreement with the preferred face-to-face orientation in the nanoaggregates on the surfaces. The facile immobilization enables on-demand preparation and use of the nanocubes in real analytical applications.

scholarly journals Hydroxycinnamic Acid Antioxidants: An Electrochemical Overview

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
José Teixeira ◽  
Alexandra Gaspar ◽  
E. Manuela Garrido ◽  
Jorge Garrido ◽  
Fernanda Borges
Keyword(s):  
Rational Design ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Phenoxyl Radical ◽  
Free Radical Scavenger ◽  
Hydroxycinnamic Acid ◽  
Hydroxycinnamic Acids ◽  
Radical Scavenger ◽  
Redox Potentials ◽  
Structure Property

Hydroxycinnamic acids (such as ferulic, caffeic, sinapic, andp-coumaric acids) are a group of compounds highly abundant in food that may account for about one-third of the phenolic compounds in our diet. Hydroxycinnamic acids have gained an increasing interest in health because they are known to be potent antioxidants. These compounds have been described as chain-breaking antioxidants acting through radical scavenging activity, that is related to their hydrogen or electron donating capacity and to the ability to delocalize/stabilize the resulting phenoxyl radical within their structure. The free radical scavenger ability of antioxidants can be predicted from standard one-electron potentials. Thus, voltammetric methods have often been applied to characterize a diversity of natural and synthetic antioxidants essentially to get an insight into their mechanism and also as an important tool for the rational design of new and potent antioxidants. The structure-property-activity relationships (SPARs) correlations already established for this type of compounds suggest that redox potentials could be considered a good measure of antioxidant activity and an accurate guideline on the drug discovery and development process. Due to its magnitude in the antioxidant field, the electrochemistry of hydroxycinnamic acid-based antioxidants is reviewed highlighting the structure-property-activity relationships (SPARs) obtained so far.

Three-Dimensional Finite-Difference Time-Domain Method Modeling of Nanowire Optical Probe

2014 ◽  
Vol 602-605 ◽  
pp. 3359-3362
Author(s):  
Chun Li Zhu ◽  
Jing Li
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Incident Light ◽  
Near Field ◽  
Three Dimensional ◽  
Polarization Direction ◽  
Near Field Imaging ◽  
Difference Time ◽  
Field Imaging

In this paper, output near fields of nanowires with different optical and structure configurations are calculated by using the three-dimensional finite-difference time-domain (3D FDTD) method. Then a nanowire with suitable near field distribution is chosen as the probe for scanning dielectric and metal nanogratings. Scanning results show that the resolution in near-field imaging of dielectric nanogratings can be as low as 80nm, and the imaging results are greatly influenced by the polarization direction of the incident light. Compared with dielectric nanogratings, metal nanogratings have significantly enhanced resolutions when the arrangement of gratings is perpendicular to the polarization direction of the incident light due to the enhancement effect of the localized surface plasmons (SPs). Results presented here could offer valuable references for practical applications in near-field imaging with nanowires as optical probes.

Structural modification strategies for the rational design of red/NIR region BODIPYs

2014 ◽  
Vol 43 (13) ◽  
pp. 4778-4823 ◽  
Author(s):  
Hua Lu ◽  
John Mack ◽  
Yongchao Yang ◽  
Zhen Shen
Keyword(s):  
Rational Design ◽  
Structural Modification ◽  
Photophysical Properties ◽  
Structure Property ◽  
Structure Property Relationships

The structure–property relationships of red/NIR region BODIPY dyes is analyzed, so that trends in their photophysical properties can be readily compared.

scholarly journals Numerical simulation of a plasmonic lens for laser light focusing

2021 ◽  
Vol 2103 (1) ◽  
pp. 012174
Author(s):  
E S Kozlova ◽  
V V Kotlyar
Keyword(s):  
Focal Spot ◽  
Laser Light ◽  
Incident Light ◽  
Lens Design ◽  
Light Wavelength ◽  
Optimal Parameters ◽  
Plasmonic Lens ◽  
Radial Polarization ◽  
Incident Light Wavelength ◽  
Difference Time

Abstract In this paper, the design of a plasmonic lens in gold and silver thin films for focusing the light with radial polarization is presented. Using the finite difference time domain method the optimal parameters of the plasmonic lens design are found. It was shown that the silver plasmonic lens produces a tight focal spot with a full width at half maximum of 0.38 of the incident light wavelength.

Dynamically tunable plasmon-induced transparency effect based on graphene metasurfaces

2021 ◽  
Author(s):  
Shuxian Chen ◽  
Junyi Li ◽  
Zicong Guo ◽  
Li Chen ◽  
Kunhua Wen ◽  
...  
Keyword(s):  
Modulation Depth ◽  
Incident Light ◽  
Polarization Angle ◽  
Refractive Index Sensitivity ◽  
Coupled Mode ◽  
Terahertz Devices ◽  
Index Sensitivity ◽  
Induced Transparency ◽  
Difference Time ◽  
Plasmon Induced Transparency

Abstract Plasmon-induced transparency (PIT) is theoretically explored with a graphene metamaterial using finite-difference time-domain numerical simulations and coupled-mode-theory theoretical analysis. In this work, the proposed structure is consisted of one rectangular cavity and three strips to generate the PIT phenomenon. The PIT window can be regulated dynamically by adjusting the Fermi level of the graphene. Importantly, the modulation depth of the amplitude can reach 90.4%. The refractive index sensitivity of the PIT window is also investigated, and the simulation result shows that a sensitivity of 1.335 THz/RIU is achieved. Additionally, when the polarization angle of the incident light is changed gradually from 0˚ to 90˚, the performances of the structure are greatly affected. Finally, the proposed structure is particularly enlightening for the design of dynamically tuned terahertz devices.

Stable perovskite solar cells with efficiency exceeding 24.8% and 0.3-V voltage loss

Science ◽  
2020 ◽  
Vol 369 (6511) ◽  
pp. 1615-1620 ◽  
Author(s):  
Mingyu Jeong ◽  
In Woo Choi ◽  
Eun Min Go ◽  
Yongjoon Cho ◽  
Minjin Kim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Noncovalent Interactions ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Structure Property ◽  
Large Area ◽  
Long Term Stability ◽  
Voltage Loss ◽  
Hole Transporting ◽  
Hole Transporting Material

Further improvement and stabilization of perovskite solar cell (PSC) performance are essential to achieve the commercial viability of next-generation photovoltaics. Considering the benefits of fluorination to conjugated materials for energy levels, hydrophobicity, and noncovalent interactions, two fluorinated isomeric analogs of the well-known hole-transporting material (HTM) Spiro-OMeTAD are developed and used as HTMs in PSCs. The structure–property relationship induced by constitutional isomerism is investigated through experimental, atomistic, and theoretical analyses, and the fabricated PSCs feature high efficiency up to 24.82% (certified at 24.64% with 0.3-volt voltage loss), along with long-term stability in wet conditions without encapsulation (87% efficiency retention after 500 hours). We also achieve an efficiency of 22.31% in the large-area cell.

scholarly journals Estimating Underwater Light Regime under Spatially Heterogeneous Sea Ice in the Arctic

2018 ◽  
Vol 8 (12) ◽  
pp. 2693 ◽  
Author(s):  
Philippe Massicotte ◽  
Guislain Bécu ◽  
Simon Lambert-Girard ◽  
Edouard Leymarie ◽  
Marcel Babin
Keyword(s):  
Sea Ice ◽  
Water Column ◽  
Attenuation Coefficient ◽  
Vertical Profile ◽  
Light Field ◽  
Incident Light ◽  
Single Point ◽  
The Arctic ◽  
Large Area ◽  
Average Irradiance

The vertical diffuse attenuation coefficient for downward plane irradiance ( K d ) is an apparent optical property commonly used in primary production models to propagate incident solar radiation in the water column. In open water, estimating K d is relatively straightforward when a vertical profile of measurements of downward irradiance, E d , is available. In the Arctic, the ice pack is characterized by a complex mosaic composed of sea ice with snow, ridges, melt ponds, and leads. Due to the resulting spatially heterogeneous light field in the top meters of the water column, it is difficult to measure at single-point locations meaningful K d values that allow predicting average irradiance at any depth. The main objective of this work is to propose a new method to estimate average irradiance over large spatially heterogeneous area as it would be seen by drifting phytoplankton. Using both in situ data and 3D Monte Carlo numerical simulations of radiative transfer, we show that (1) the large-area average vertical profile of downward irradiance, E d ¯ ( z ) , under heterogeneous sea ice cover can be represented by a single-term exponential function and (2) the vertical attenuation coefficient for upward radiance ( K L u ), which is up to two times less influenced by a heterogeneous incident light field than K d in the vicinity of a melt pond, can be used as a proxy to estimate E d ¯ ( z ) in the water column.

scholarly journals Combining Defects in a Single Nanographene: A Fully Helical Saddle Ribbon

Synlett ◽  
2019 ◽  
Vol 30 (09) ◽  
pp. 997-1002 ◽  
Author(s):  
Carlos Cruz ◽  
Silvia Castro-Fernández ◽  
Ermelinda Maçôas ◽  
Alba Millán ◽  
Araceli Campaña
Keyword(s):  
Organic Synthesis ◽  
Carbon Nanostructures ◽  
Nonlinear Optical ◽  
Photophysical Properties ◽  
Structure Property ◽  
Chiroptical Properties ◽  
Curved Structures ◽  
Structure Property Relationships ◽  
Linear And Nonlinear ◽  
Controlled Preparation

The controlled preparation of well-defined distorted nanographenes by a bottom-up approach based on organic synthesis permits the direct establishment of unprecedented structure–property relationships in carbon nanostructures. The simultaneous incorporation of various defects in nanographenes affords highly curved structures with novel or enhanced photophysical properties. In this sense, we recently reported a fully helical and saddle-shaped nanographene ribbon containing the first undecabenzo[7]helicene unit. Both its linear and nonlinear optical properties are enhanced in comparison with those of other partially π-extended [7]helicenes. Moreover, the new superhelicene exhibits the highest emission dissymmetry factor (g lum) reported to date for a homochiral nanographene. The combination of both nonlinear and chiroptical properties in nanographenes opens up new possible future applications for those distorted nanostructures.1 Introduction2 Synthesis of Embedded Seven-Membered Rings3 Combination of Defects: Seven-Membered Rings and π-Extended Helicenes4 Conclusions and Outlook

Atomically dispersed M–N–C catalysts for the oxygen reduction reaction

2020 ◽  
Vol 8 (44) ◽  
pp. 23187-23201 ◽  
Author(s):  
Hao Xu ◽  
Dan Wang ◽  
Peixia Yang ◽  
Anmin Liu ◽  
Ruopeng Li ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Rational Design ◽  
Reduction Reaction ◽  
Structure Property

The systematic summarization of synthesis–structure–property–mechanism correlations provides guidance for the rational design of an atomically dispersed M–N–C catalyst for the ORR.

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