Ostwald Ripening of the InAsSbP/InAs(100) Quantum Dots in the Framework of the Modified LSW Theory

2017 ◽  
Vol 9 (2) ◽  
pp. 02025-1-02025-6
Author(s):  
B. V. Ivanskii ◽  
◽  
R. D. Vengrenovich ◽  
V. I. Kryvetskyi ◽  
Yu. M. Kushnir ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ostwald Ripening ◽  
Lsw Theory

AQUEOUS SYNTHESIS OF HIGH QUANTUM YIELD AND MONODISPERSED THIOL-CAPPED CdxZn1-xTe QUANTUM DOTS BASED ON ELECTROCHEMICAL METHOD

NANO ◽  
2012 ◽  
Vol 07 (02) ◽  
pp. 1250011 ◽  
Author(s):  
JUNWEI LI ◽  
YANG JIANG ◽  
YUGANG ZHANG ◽  
DI WU ◽  
ANQI LUO ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Electrochemical Method ◽  
Large Scale ◽  
Ostwald Ripening ◽  
Visible Absorption ◽  
Aqueous Synthesis ◽  
Transmission Electron

A facile green approach has been developed to control the growth regime in the aqueous synthesis of CdxZn1-xTe semiconductor quantum dots (QDs) based on the electrochemistry method. The Low growth temperature and slow injection of Te precursor are used to prolong the diffusion controlled stage and thus suppress Ostwald ripening during the nanocrystal growth. The experimental results showed that a low concentration of Te precursor will definitely influence the growth procedure. The UV–visible absorption spectra, as well as transmission electron microscopy (TEM) shows the QDs a good monodispersity at any interval of the reaction procedure. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs have high crystallinity and cubic structure. The size and composition-dependent fluorescent emission wavelength of the resultant CdxZn1-xTe alloyed QDs can be tuned from 460 to 610 nm, and their photoluminescent quantum yield can reach up to 70%. Especially in the wavelength range of 510–578 nm, the overall PL QYs of the as-prepared CdxZn1-xTe QDs were above 50%. The current work suggests that electrochemical method is an attractive approach to the synthesis of high-quality II-VI ternary alloyed semiconductor QDs at large-scale with a prominent cost advantage.

Narrowing the Photoluminescence of Aqueous CdTe Quantum Dots via Ostwald Ripening Suppression Realized by Programmed Dropwise Precursor Addition

2018 ◽  
Vol 122 (20) ◽  
pp. 11109-11118 ◽  
Author(s):  
Xiaodan Huang ◽  
Lihong Jing ◽  
Stephen V. Kershaw ◽  
Xiaojun Wei ◽  
Haoran Ning ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ostwald Ripening ◽  
Cdte Quantum Dots

scholarly journals Combination of Cation Exchange and Quantized Ostwald Ripening for Controlling Size Distribution of Lead Chalcogenide Quantum Dots

2017 ◽  
Vol 29 (8) ◽  
pp. 3615-3622 ◽  
Author(s):  
Changwang Zhang ◽  
Yong Xia ◽  
Zhiming Zhang ◽  
Zhen Huang ◽  
Linyuan Lian ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cation Exchange ◽  
Size Distribution ◽  
Ostwald Ripening ◽  
Lead Chalcogenide

Size distribution of InAsSbP/InAs(100) quantum dots in the frames of modified for surface LSW theory

2014 ◽  
Vol 49 (4) ◽  
pp. 158-164 ◽  
Author(s):  
R. D. Vengrenovich ◽  
B. V. Ivanskii ◽  
I. I. Panko ◽  
Yu. M. Kushnir ◽  
V. I. Kryvetskyi
Keyword(s):  
Quantum Dots ◽  
Size Distribution ◽  
Lsw Theory

Synthesis of Highly Luminescent CdSe/ZnCdS Quantum Dots with Deep-Red Emissions

2016 ◽  
Vol 848 ◽  
pp. 466-471
Author(s):  
Jing Tan ◽  
Jian Quan Guo ◽  
Wei Na Wu ◽  
Qian Shi ◽  
Wei Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ostwald Ripening ◽  
Ripening Process ◽  
Emission Efficiency ◽  
Xrd Diffraction ◽  
Zinc Blende ◽  
Bio Imaging ◽  
Zinc Blende Structure

CdSe cores with larger radius were prepared by means of two-steps injection of the Cd precursor. Efforts were made to avoid the Ostwald ripening process during the quantum dots grown up. The prepared CdSe cores showed zinc-blende structure with size exceeded over 7 nm. The emission efficiency of prepared quantum dots were 15%, while it increased drastically up to 43% after the formation of ZnCdS shells on the CdSe cores. Morphologies and structures of the quantum dots were characterized by HR-TEM and XRD diffraction. The obtained quantum dots with emission wavelengths more than 660 nm were expected to find their applications in bio-imaging and plant illuminations.

Statistical Mechanics of Phase Coarsening

1983 ◽  
Vol 21 ◽  
Author(s):  
M.E. Glicksman ◽  
P.W. Voorhees
Keyword(s):  
Statistical Mechanics ◽  
Particle Distribution ◽  
Ostwald Ripening ◽  
Volume Fraction ◽  
High Volume ◽  
Distribution Functions ◽  
Average Particle ◽  
Two Phase ◽  
Phase Coarsening ◽  
Lsw Theory

ABSTRACTPhase coarsening, also termed Ostwald ripening, is generally thought to be a slow, diffusion-controlled process which occurs subsequent to phase separation under extremely small under- or over-saturation levels. The theory due to Lifshitz, Slyzov, and Wagner (LSW), which predicts the coarsening kinetics and the particle distribution function is applicable to dilute systems only, in which particle-particle interactions are unimportant. Most practical systems, however, have large enough volume fractions of the dispersed phase to violate the essential assumptions of LSW theory. Recent progress will be described on simulating Ostwald ripening in randomly dispersed, high volume fraction systems. A fast algorithm for solving the multiparticle diffusion problem (MDP) will be described, permitting simulation of coarsening dynamics by cyclic time-stepping and updating the diffusion solution for large random particle arrays. The rate constants, controlling the growth of the average particle, and the particle distribution functions were obtained by numerical simulations up to a volume fraction of 0.55. A new statistical mechanics theory has now been developed which reproduces the MDP simulation data accurately, and finally makes clear how the linear mean-field approximations employed by LSW theory must be modified to describe real systems. The new theory provides a comprehensive approach to understanding microstructural coarsening in two-phase systems.

scholarly journals Ostwald Ripening of the Platinum Nanoparticles in the Framework of the Modified LSW Theory

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
R. D. Vengrenovich ◽  
B. V. Ivanskii ◽  
I. I. Panko ◽  
S. V. Yarema ◽  
V. I. Kryvetskyi ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Reaction Rate ◽  
Ostwald Ripening ◽  
Pt Nanoparticles ◽  
Parallel Mechanisms ◽  
Wagner Model ◽  
Lsw Theory ◽  
Chemical Reaction Rate ◽  
Rate Comparison

An analysis of the experimental data related to the mechanism of Pt particles sintering has been carried out using the modified LSW theory. The size distribution for the Pt nanoparticles at the stage of Ostwald ripening fits the generalized Lifshitz-Slyozov-Wagner model calculated with the assumption of two parallel mechanisms involved in the nanoparticles growth (dissolution): diffusion and Wagner’s (controlled by the chemical reaction rate). Comparison between the experimental histograms and the curves calculated theoretically proves the governing role of the Wagner’s mechanism (chemical reaction) in the Pt nanoparticles growth.

Small-Angle X-ray Scattering Size Parameters and Higher Moments of the Particle-Size Distribution Function in the Asymptotic Stage of Ostwald Ripening

1995 ◽  
Vol 28 (5) ◽  
pp. 553-560 ◽  
Author(s):  
J. Möller ◽  
R. Kranold ◽  
J. Schmelzer ◽  
U. Lembke
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Ostwald Ripening ◽  
Distribution Functions ◽  
Higher Moments ◽  
X Ray ◽  
Diffusion Limited ◽  
X Ray Scattering ◽  
Lsw Theory ◽  
Kinetics Of

Small-angle X-ray scattering (SAXS) is a powerful tool to study the kinetics of phase separation in materials. A simple procedure is presented that allows one to prove if the particle-size distribution established in a system in the late stages of phase separation corresponds to the predictions of the classical Lifshitz–Slyozov–Wagner (LSW) theory for the asymptotic stage of Ostwald ripening. The method is based on the correlations between certain SAXS size parameters and the higher moments of the LSW size distribution functions for diffusion-limited or reaction-limited ripening. It is suggested that the use of these size parameters, which can be obtained with high accuracy from the scattering curve, is frequently more advantageous than a direct comparison of the experimentally obtained size distributions with the asymptotic size-distribution functions predicted by the LSW theory. The method is applicable if the suppositions made in the LSW theory that the precipitated particles should be homogeneous spheres with volume fraction tending to zero are fulfilled. The method is applied to a photochromic glass; although the silver-halide precipitates contained in the glass develop according to the power law of diffusion-limited Ostwald ripening, their size distribution is shown not to correspond to the features of the LSW size distribution. Consequently, in this case the LSW theory cannot describe quantitatively the kinetics of ripening.

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