Interparticle separation dependent dynamics in optical matter (Conference Presentation)

2018 ◽  
Author(s):  
Yuval Yifat ◽  
Delphine Coursault ◽  
Curtis W. Peterson ◽  
John Parker ◽  
Norbert F. Scherer
Keyword(s):  
Interparticle Separation

Optical Interactions and Photoluminescence Properties of Wide-Bandgap Nanocrystallites

2003 ◽  
Vol 789 ◽  
Author(s):  
Leah Bergman ◽  
Xiang-Bai Chen ◽  
Jesse Huso ◽  
Althea Walker ◽  
John L. Morrison ◽  
...  
Keyword(s):  
Free Exciton ◽  
Vacuum State ◽  
Mean Free Path ◽  
Wide Bandgap ◽  
Photoluminescence Properties ◽  
Interparticle Separation ◽  
Intensity Saturation ◽  
The Mean ◽  
The Impact ◽  
Excitonic Recombination

ABSTRACTThe UV-photoluminescence (PL) properties of GaN and ZnO nanocrystallites and nanocrystallite ensembles were studied utilizing micro-photoluminescence. We address the origin of the light emissions of the nanocrystallite as to whether it is due a bandgap or excitonic recombination process. The other topic presented here focuses on the interaction of the laser with a collective of crystallites; we address the phenomena of intensity saturation at a high density of laser excitations as well as the impact of the vacuum state on the PL characteristics. Our analysis indicates that the PL of both GaN and ZnO nanocrysallites is excitonic-like and very similar to the behavior of the free exciton in bulk materials. Additionally, we attribute the intensity saturation of GaN and ZnO to the laser heating and heat trapping which takes place in the enclosure of the nanocrystallite ensemble. In vacuum the PL energy was found to exhibit a strong PL energy redshift relative to the PL in air. We attribute the observed shift to a thermal effect and analyze it in terms of the conditions enabling a convective cooling in the ensemble: the mean free path of air in atmospheric pressure and in vacuum relative to the interparticle separation inside the ensemble.

Bonding state energy of metal nanoparticle dimer and its dependence on nanosphere size and interparticle separation

2018 ◽  
Vol 27 (02) ◽  
pp. 1850018 ◽  
Author(s):  
Margareta Vania Stephanie ◽  
Alexander A. Iskandar ◽  
May-On Tjia
Keyword(s):  
Integral Formula ◽  
Incident Light ◽  
Dielectric Medium ◽  
Metal Nanoparticle ◽  
Coupling Energy ◽  
Bonding State ◽  
Single Function ◽  
Interparticle Separation ◽  
Parallel Polarization ◽  
Energy Formula

A study is conducted regarding the effects of particle size [Formula: see text] and interparticle separation [Formula: see text] on the electromagnetic (plasmon) coupling in a dimer of two identical metal nanospheres. The dimer states are modeled as the hybridized bonding and antibonding states of two isolated plasmon states, with the associated energies given in terms of the isolated plasmon energy ([Formula: see text], the coupling energy ([Formula: see text] and the overlap integral ([Formula: see text] of the constituent plasmonic fields. The resonance absorption energies of the isolated plasmon and the dimer in certain dielectric medium are calculated according to the Mie theory for incident light of parallel polarization along the dimer axis. The results are fitted with the bonding state energies of both Au and Ag nanosphere dimers for [Formula: see text] ranging within 10–20[Formula: see text]nm and x varied within [Formula: see text]–200[Formula: see text]nm in compliance with the restricted consideration of dipole absorption spectra. The excellent fits of the bonding state energies [Formula: see text] for the ranges of [Formula: see text] and [Formula: see text] variations are consistently achieved with [Formula: see text] around 0.99 by a single function of the form [Formula: see text] where [Formula: see text] and [Formula: see text] vary with the nanosphere materials and the surrounding media considered. This result suggests the possible relation of the best fitted functional form [Formula: see text] with the underlying physical mechanism.

Calculation of Local Fields for Clusters of Ellipsoids Within the T-Katrix Approach

1990 ◽  
Vol 195 ◽  
Author(s):  
Manuel Gomez ◽  
Luis F. Fonseca ◽  
Luis Cruz ◽  
William Vargas
Keyword(s):  
Electric Fields ◽  
Interparticle Distance ◽  
Local Fields ◽  
Matrix Formalism ◽  
Exponential Relationship ◽  
Long Wavelength ◽  
Interparticle Separation ◽  
T Matrix ◽  
Angle Of Rotation

ABSTRACTA T-matrix formalism is used to calculate local electric fields around clusters of prolate ellipsoids in the long wavelength regime. The calculations are performed as a function of interparticle distance as well as angle of orientation. The observed red shifts in the resonant wavelengths of the characteristic peaks are shown to obey an exponential relationship as a function of interparticle separation and a sinusoidal relationship as a function of angle of rotation of the ellipsoid. The behavior of the cluster is discussed and the two effects, of separation and rotation, are compared.

scholarly journals Deposition of Silver Nanoparticles on Indium Tin Oxide Substrates by Plasma-Assisted Hot-Filament Evaporation

2020 ◽  
Author(s):  
Abtisam Hasan Hamood Al-Masoodi ◽  
Boon Tong Goh ◽  
Ahmed H.H. Al-Masoodi ◽  
Wan Haliza Binti Abd Majid
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ag Nanoparticles ◽  
Noble Metals ◽  
Quantum Confinement Effect ◽  
High Electron ◽  
Plasmon Excitation ◽  
Light Region ◽  
Interparticle Separation ◽  
Hot Filament

Nanoparticles of noble metals have unique properties including large surface energies, surface plasmon excitation, quantum confinement effect, and high electron accumulation. Among these nanoparticles, silver (Ag) nanoparticles have strong responses in visible light region due to its high plasmon excitation. These unique properties depend on the size, shape, interparticle separation and surrounded medium of Ag nanoparticles. Indium tin oxide (ITO) is widely used as an electrode for flat panel devices in such as electronic, optoelectronic and sensing applications. Nowadays, Ag nanoparticles were deposited on ITO to improve their optical and electrical properties. Plasma-assisted hot-filament evaporation (PAHFE) technique produced high-density of crystalline Ag nanoparticles with controlling in the size and distribution on ITO surface. In this chapter, we will discuss about the PAHFE technique for the deposition of Ag nanoparticles on ITO and influences of the experimental parameters on the physical and optical properties, and electronic structure of the deposited Ag nanoparticles on ITO.

Absorption length for photon propagation in highly dense colloidal dispersions

1998 ◽  
Vol 13 (12) ◽  
pp. 3463-3467 ◽  
Author(s):  
Rajeev Garg ◽  
Robert K. Prud'homme ◽  
Ilhan A. Aksay ◽  
Feng Liu ◽  
Robert R. Alfano
Keyword(s):  
Light Transmission ◽  
Continuous Phase ◽  
Colloidal Dispersions ◽  
Interparticle Spacing ◽  
Absorption Length ◽  
Photon Propagation ◽  
High Particle Concentration ◽  
High Particle ◽  
Interparticle Separation ◽  
The Difference

The absorption length for photon propagation in highly concentrated colloidal dispersions calculated from temporal intensity profiles of 100 femto-second pulses is much longer than the absorption length obtained from the measurements of static light transmission in the pure continuous phase fluid. The difference between these two values is explained on the basis of small interparticle spacing at high particle concentration and hence shorter paths traveled by photons through the absorbing medium relative to the total diffusive path in the dispersion. The two values are in good agreement when the absorption length is rescaled with the interparticle separation.

Role of cohesive energy on the interparticle coalescence behavior of dispersed nanoparticles subjected to energetic ion irradiation

2010 ◽  
Vol 25 (5) ◽  
pp. 814-820 ◽  
Author(s):  
Sayan Bayan ◽  
Dambarudhar Mohanta
Keyword(s):  
Cohesive Energy ◽  
Liquid Drop ◽  
Ion Irradiation ◽  
Nanoparticle Growth ◽  
Size Dependent ◽  
Interparticle Separation ◽  
Nanoparticle System ◽  
Particle Coalescence ◽  
Thermal Stability Of

The present work reports on the conditions of nanoparticle growth and splitting under energetic ion irradiation. Cohesive energy that determines the thermal stability of a given nanoparticle system was calculated by extending surface area difference (SAD) and liquid drop model (LDM). Based on the size-dependent cohesive energy calculations, the interparticle coalescence mechanism is discussed for a ZnS-based nanoparticle system with special reference to a variety of matrices. The interparticle separation is found to play key role in particle–particle coalescence leading to nanoparticle growth or partial evaporation that results in splitting.

On the interaction of colloidal particles IV. general mathematical theory for two identical particles

1951 ◽  
Vol 47 (1) ◽  
pp. 217-229 ◽  
Author(s):  
S. Levine
Keyword(s):  
Free Energy ◽  
Colloidal Particles ◽  
Double Layers ◽  
Interparticle Separation ◽  
Special Assumption ◽  
Energy Of Interaction ◽  
Set Up ◽  
Ionic Density ◽  
Further Development ◽  
General Mathematical Theory

AbstractA general theory of the interaction of two charged identical colloidal particles of arbitrary shape is developed. An expression for the Helmholtz free energy of the electric double layers is obtained by the methods of statistical mechanics. The condition that there is equilibrium between the ions adsorbed on the surfaces of the colloidal particles and those dissolved in the dispersion medium is accounted for by requiring that the free energy of the whole system be a minimum with respect to variation of the ionic density on the surfaces.The theory presented here is a further development of the work of Verwey and Overbeek. The conclusions of this paper are that in dilute sols, to which the present investigations are restricted, the results of these authors require extension in two directions. First, there is a correction to the mutual energy of two particles, due to the Coulomb interaction of the ions in the bulk of the solution. Secondly, no special assumption concerning the relation between the surface potential (or charge) and interparticle separation need be introduced. The equations set up to determine the free energy of interaction at the same time yield the ‘adsorption isotherm’ for the ion type which is common to the solution and the surface of the particle.

Inelastic X-ray scattering and high-frequency dynamics of molecular liquids

2004 ◽  
Vol 76 (1) ◽  
pp. 79-89 ◽  
Author(s):  
E. Pontecorvo ◽  
R. Di Leonardo ◽  
C. Masciovecchio ◽  
G. Ruocco ◽  
B. Ruzicka ◽  
...  
Keyword(s):  
High Temperature ◽  
Ambient Temperature ◽  
High Frequency ◽  
Molecular Liquids ◽  
Vibrational Dynamics ◽  
X Ray ◽  
X Ray Scattering ◽  
Interparticle Separation ◽  
Scattering Technique ◽  
Ray Scattering

The recently developed inelastic X-ray scattering technique opens a new kinematic region at the observation of molecular liquids vibrational dynamics over the lengthscales of the interparticle separation. We illustrate the capabilities of this powerful technique through the results obtained from liquid glycerol. A detailed analysis of the high-frequency vibrational dynamics of this system at ambient temperature is reported. New results in the study of structural relaxational dynamics in the high-temperature range (up to T = 560 K) are also discussed.

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