scholarly journals Light-Scattering Simulations from Spherical Bimetallic Core–Shell Nanoparticles

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 359
Author(s):  
Francesco Ruffino
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Bimetallic Nanoparticles ◽  
Dominant Role ◽  
Scattered Light ◽  
Specific Interaction ◽  
Surface Enhanced Raman Spectroscopy ◽  
Localized Surface Plasmon ◽  
Core Shell ◽  
The Core

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.

scholarly journals Modelling the Optical Properties of Soot Particles under Various Aging Conditions

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Kangwei Li ◽  
Mingming Yan ◽  
Jiandong Shen ◽  
Xin Zhang ◽  
Chunmei Geng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Species ◽  
Absorption Efficiency ◽  
Optical Characteristics ◽  
Core Shell ◽  
Mixing State ◽  
Coating Materials ◽  
Soot Particles ◽  
The Core ◽  
Aging Conditions

As atmospheric fresh soot particles age, they become coated with other chemical species. This transforms their physicochemical properties and affects their optical characteristics, which is of great importance to air quality, the environment and climate change. One of the predominantly occurring states of soot particles in the ambient environment is the core-shell mixing state. In this study, we used the core-shell model to calculate the optical absorption, scattering and extinction efficiency, absorption proportion and absorption exponent of coated soot particles. We then investigated the effects of different core sizes (D0), incident wavelengths (λ), coating materials and coating thicknesses on these optical characteristics. Absorption efficiency and absorption proportion of soot particles decreased as the coating became thicker, at core sizes of D0 = 20, 50 and 100 nm and λ = 405, 532 and 781 nm, regardless of the type of coating material. As the coating thickness increased, the absorption exponent (β) of inorganic-coated soot particles tended to rise and then fall, while the β value of organic-coated soot particles kept increasing. Our results advance our scientific understanding of the interaction of optical properties with chemical composition, mixing state, and aging processes of soot particles in the atmosphere.

Regulating the electronic and optical properties of GaN/InN core/shell nanowires: A first-principles study

2020 ◽  
Vol 34 (25) ◽  
pp. 2050214 ◽  
Author(s):  
Chang Liu ◽  
Enling Li ◽  
Tuo Peng ◽  
Kaifei Bai ◽  
Yanpeng Zheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Core Shell ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Gan Nanowires ◽  
The Core ◽  
Light Region ◽  
Calculation Results ◽  
Shell Nanowires

In this paper, electronic and optical properties of GaN/InN core/shell nanowires (CSNWs) have been theoretically investigated through the first principles calculations. The binding energy of In and N atoms on surface of six crystal planes along the [Formula: see text]-axis of GaN nanowires are all negative, which indicate that In and N atoms can be effectively deposited on the surface of GaN nanowires and preparing GaN/InN CSNWs is feasible theoretically. Calculation results of electronic properties indicate that the core/shell ratio and diameter of GaN/InN CSNWs have significant effect on the band structure, bandgap can be effectively adjusted when keeping the number of GaN layers unchanged and changing the number of InN layers. Moreover, with the increase in the number of InN layers, the absorption spectrum of GaN/InN CSNW has significant redshift and few weak absorption peaks appear in the visible light region.

scholarly journals Optical Characterization of Homogeneous and Heterogeneous Intralipid-Based Samples

2020 ◽  
Vol 10 (18) ◽  
pp. 6234
Author(s):  
Ines Delfino ◽  
Maria Lepore ◽  
Rosario Esposito
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Scattered Light ◽  
Industrial Applications ◽  
Point Of View ◽  
Turbid Media ◽  
Time Resolved ◽  
Propagation Of Light ◽  
First Time

Different scattering processes take place when photons propagate inside turbid media. Many powerful experimental techniques exploiting these processes have been developed and applied over the years in a large variety of situations from fundamental and applied research to industrial applications. In the present paper, we intend to take advantage of Static Light Scattering (SLS), Dynamic Light Scattering (DLS), and Time-Resolved Transmittance (TRT) for investigating all the different scattering regimes by using scattering suspensions in a very large range of scatterer concentrations. The suspensions were prepared using Intralipid 20%, a material largely employed in studies of the optical properties of turbid media, with concentrations from 10−5% to 50%. By the analysis of the angular and temporal dependence of the scattered light, a more reliable description of the scattering process occurring in these samples can be obtained. TRT measurements allowed us to obtain information on the reduced scattering coefficient, an important parameter largely used in the description of the optical properties of turbid media. TRT was also employed for the detection of inclusions embedded in Intralipid suspensions, by using a properly designed data analysis. The present study allowed us to better elucidate the dependence of scattering properties of Intralipid suspensions in a very large concentration range and the occurrence of the different scattering processes involved in the propagation of light in turbid media for the first time to our knowledge. In so doing, the complementary contribution of SLS, DLS, and TRT in the characterization of turbid media from an optical and structural point of view is strongly evidenced.

Ag2S/ZnS nanocomposites: Synthesis, structure and optical properties

2020 ◽  
pp. 2150033
Author(s):  
M. A. Ramazanov ◽  
S. G. Nuriyeva ◽  
H. A. Shirinova ◽  
A. H. Karimova ◽  
M. A. Nuriyev
Keyword(s):  
Optical Properties ◽  
Structural Investigation ◽  
Emission Spectra ◽  
Structural Features ◽  
Core Shell ◽  
Zns Nanoparticles ◽  
Sem Images ◽  
X Ray ◽  
The Core ◽  
Novel Method

Ag2S/ZnS nanocomposites were synthesized using a novel method, and their structural features and optical properties were also investigated. For the structural investigation of the core/shell-like nanocomposites, X-ray powder diffraction technique (XRD) and scanning electron microscopy (SEM) were used. Optical features of Ag2S/ZnS nanocomposites were studied by UV-Vis absorption and photoluminescence spectroscopy (PL). According to the SEM images, the sizes of the Ag2S, ZnS nanoparticles and Ag2S/ZnS core/shell-like nanocomposites are in the region of the 10–15; 25–50 and 15–80 nm, respectively. Furthermore, the absorption spectroscopy indicates that the bandgap of Ag2S/ZnS nanocomposites is approximately 2.4 eV. By comparison of the intensities of the emission spectra, it was clear that the intensity of Ag2S/ZnS is much lower than that of ZnS.

Insight into growth of Au–Pt bimetallic nanoparticles: anin situXAS study

2017 ◽  
Vol 24 (4) ◽  
pp. 825-835 ◽  
Author(s):  
Chandrani Nayak ◽  
D. Bhattacharyya ◽  
K. Bhattacharyya ◽  
A. K. Tripathi ◽  
R. D. Bapat ◽  
...  
Keyword(s):  
Bimetallic Nanoparticles ◽  
Energy Dispersive ◽  
Core Shell ◽  
One Pot ◽  
X Ray ◽  
The Core ◽  
One Pot Synthesis ◽  
X Ray Absorption ◽  
Insight Into

Au–Pt bimetallic nanoparticles have been synthesized through a one-pot synthesis route from their respective chloride precursors using block copolymer as a stabilizer. Growth of the nanoparticles has been studied by simultaneousin situmeasurement of X-ray absorption spectroscopy (XAS) and UV–Vis spectroscopy at the energy-dispersive EXAFS beamline (BL-08) at Indus-2 SRS at RRCAT, Indore, India.In situXAS spectra, comprising both X-ray near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) parts, have been measured simultaneously at the Au and PtL3-edges. While the XANES spectra of the precursors provide real-time information on the reduction process, the EXAFS spectra reveal the structure of the clusters formed in the intermediate stages of growth. This insight into the formation process throws light on how the difference in the reduction potential of the two precursors could be used to obtain the core–shell-type configuration of a bimetallic alloy in a one-pot synthesis method. The core–shell-type structure of the nanoparticles has also been confirmed byex situenergy-dispersive spectroscopy line-scan and X-ray photoelectron spectroscopy measurements within situion etching on fully formed nanoparticles.

Synthesis and Characterization of Environmentally Responsive Core-Shell Hydrogel Nanoparticles

2000 ◽  
Vol 662 ◽  
Author(s):  
Clinton D. Jones ◽  
Christina Baker ◽  
L. Andrew Lyon
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Light Scattering ◽  
Synthesis And Characterization ◽  
Core Shell ◽  
The Core ◽  
Environmentally Responsive ◽  
Responsive Hydrogels ◽  
Measured Phase

AbstractWe report the synthesis of environmentally responsive hydrogels as nano-sized particles with core-shell morphologies. Composed of co-polymers of N-isopropylacrylamide with various co-monomers, these materials can be designed to render the core and shell responsive to different stimuli or to different magnitudes of the same stimulus. The measured phase transitions reflect the degree to which the two materials interact and thereby modulate the responsivity of the particle as a whole. Characterization of these materials is accomplished via dynamic light scattering and electron microscopy.

Synthesis and Characterization of the Core-Shell CdTe/ZnS Quantum Dots

2009 ◽  
Vol 60-61 ◽  
pp. 165-169 ◽  
Author(s):  
Shi Chao Xu ◽  
Cui Cui Yao ◽  
Ji Mei Zhang ◽  
Zhao Dai ◽  
Guo Zheng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Colloidal Particles ◽  
Resonance Energy ◽  
Quantum Yields ◽  
Diagnostic Process ◽  
Core Shell ◽  
The Core ◽  
Average Size ◽  
Cdte Core

Core-shell quantum dots are colloidal particles consisting of a semiconductor core and a shell material as an outer coating layer. It can be utilized to develop sensitive methods for the detection of specific biological entities, such as microbial species, their transcription products, and single genes etc. The goal of current research is to synthesize CdTe and core-shell CdTe/ZnS quantum dots (QDs) with an improved process, and to investigate their properties. Well-dispersed CdTe core was prepared in aqueous phase with using 3-mercaptopropionic acid (MPA) as stabilizer under conditions of pH 9.1, temperature of 100 °C, refluxing for 6h, and mol ratio of Cd2+/Te2-/MPA is 1:0.5:2.4. Average size of 8 nm CdTe core was conformed via transmission electron microscopy (TEM). Core-shell CdTe/ZnS QDs were then synthesized to improve the optical properties and biocompatibility of CdTe core. Various conditions were researched to obtain the core-shell QDs with the best optical properties, such as quantum yields, fluorescence intensity etc. The results indicated that the core-shell qualified CdTe/ZnS was prepared under conditions of pH 9.0, temperature of 45 °C, refluxing for 1h, and mol ratio of CdTe/S2-/Zn2+ is 4/1/1. CdTe/ZnS with average size of 10 nm were achieved and conformed via TEM. Moreover, red shift of a maximum emission wavelength from 547 nm of CdTe to 587 of CdTe/ZnS was observed via fluorescence spectrum (FS), which inferred the growth of QDs and formation of ZnS shells. The achieved ZnS shell make CdTe core less toxic and more biocompatible, it will be useful in biological labeling, diagnostic process and biosensing system based on fluorescence resonance energy transition (FRET).

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