Photoluminescence of as an indication of crystal structure and particle size in nanoparticles synthesized by flame spray pyrolysis

Dosev, Dosi; Guo, Bing; Kennedy, Ian M.

doi:10.1016/j.jaerosci.2005.08.009

Cited by 116 publications

(72 citation statements)

References 38 publications

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“…The Gibbs-Thomson effect favors crystallization of nanoparticles in high-pressure polymorphs due to additional hydrostatic pressure P (Dosev et al, 2006;Skandan et al, 1992) 4…”

Section: Non-optical Effects Of Reduced Particle Sizementioning

confidence: 99%

Nanophosphor Coatings: Technology and Applications, Opportunities and Challenges

Kubrin

2014

KONA

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The particle size of conventional commercial phosphor powders used in lighting and displays is in the range from several micrometers to tens of micrometers and it is known that submicrometer-sized phosphors can facilitate a decrease in their consumption and improved resolution of phosphor screens. When the particle size becomes comparable to wavelengths of light, the optical properties of phosphor powders undergo remarkable qualitative changes so that the luminescence performance of nanophosphor screens, along with a very pronounced influence of the particle size, becomes dependent on several additional parameters such as packing density of nanoparticles, refractive index and chemical composition of the medium between them. This brings about both advantages and disadvantages which are discussed in this review of recent literature on the synthesis, deposition, and applications of nanophosphors.

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“…The Gibbs-Thomson effect favors crystallization of nanoparticles in high-pressure polymorphs due to additional hydrostatic pressure P (Dosev et al, 2006;Skandan et al, 1992) 4…”

Section: Non-optical Effects Of Reduced Particle Sizementioning

confidence: 99%

Nanophosphor Coatings: Technology and Applications, Opportunities and Challenges

Kubrin

2014

KONA

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“…The void time is the time required for filling the solution into the channel completely and the elution time is a time required to get the particles of interest to the channel exit. So the retention ratio can be derived experimentally as (7) where V 0 is a void volume, V e is an elution volume, t 0 is a void time, and t e is an elution time. This equation is valid when the flow is a constant fluid flow with time.…”

Section: Micro Efff Theoretical Backgroundmentioning

confidence: 99%

“…The uniformity of size of nanoparticles, within some practical limits, is therefore a precondition to their use. Although some methods for particle synthesis offer good monodispersity, other methods may yield broader size distributions [7]. In the latter case, methods for particle size separation are needed.…”

Section: Introductionmentioning

confidence: 99%

ζ-Potential analyses using micro-electrical field flow fractionation with fluorescent nanoparticles

Chang

Dosev

Kennedy

2007

Sensors and Actuators B: Chemical

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Increasingly growing application of nanoparticles in biotechnology requires fast and accessible tools for their manipulation and for characterization of their colloidal properties. In this work we determine the zeta-potentials for polystyrene nanoparticles using micro electrical field flow fractionation (μ-EFFF) which is an efficient method for sorting of particles by size. The data obtained by μ-EFFF were compared to zeta potentials determined by standard capillary electrophoresis. For proof of concept, we used polystyrene nanoparticles of two different sizes, impregnated with two different fluorescent dyes. Fluorescent emission spectra were used to evaluate the particle separation in both systems. Using the theory of electrophoresis, we estimated the zeta-potentials as a function of size, dielectric permittivity, viscosity and electrophoretic mobility. The results obtained by the μ-EFFF technique were confirmed by the conventional capillary electrophoresis measurements. These results demonstrate the applicability of the μ-EFFF method not only for particle size separation but also as a simple and inexpensive tool for measurements of nanoparticles zeta potentials.

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“…[20,21] SP involves extreme synthesis conditions occurring at the level of a micrometer-sized aerosol droplet in a disperse system, thus enabling the synthesis of metastable structures, as previously reported. [21,22] There are certain process parameters, such as high heating and cooling rates, short residence times, and an additional thermal treatment, which may affect the yield of either thermodynamically (YAG, YAM) or kinetically (YAP) stable phases. [12] The introduction of organic components into the solution is becoming increasingly popular, since these components provide the retention of the proper stoichiometry during the process, and the reaction that occurs in the solution leads to volume precipitation and the formation of dense particles.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Cerium‐Activated Yttrium Aluminate Based Fine Phosphors by an Aerosol Route

et al. 2012

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Polycrystalline fine powders of yttrium aluminate doped with Ce3+ were synthesised by spray pyrolysis of a polymeric precursor, which was obtained by dissolving the corresponding nitrates in a solution of ethylenediaminetetraacetic acid (EDTA) in ethylene glycol (EG). Aerosol decomposition was performed at 550 °C followed by an additional thermal treatment (900–1100 °C). The yield of either a single yttrium aluminium perovskite (YAP) phase or a single yttrium aluminium garnet (YAG) phase was investigated as a function of the predefined yttrium/aluminium ratio, the cerium doping concentration, the processing temperature, and the thermal‐treatment regime, which included the variation of the heating and cooling rates (dT/dt), the residence time (τ), and the atmosphere. Changes in the composition and structure of the precursor during thermal decomposition were investigated by thermogravimetric and differential thermal analysis (TGA/DTA) and FTIR spectroscopy. The particle morphology and structure were analysed by a combination of scanning electron microscopy and energy‐dispersive X‐ray spectroscopy (SEM/EDS) and by high‐resolution transmission electron microscopy (HR‐TEM). The structural refinement was based on the phase identification performed by X‐ray powder diffraction (XRPD). The emission spectra were recorded within the range 325–800 nm by applying excitation wavelengths of 297 (YAP) and 450 nm (YAG). The employed synthesis conditions assured the formation of spherical, non‐agglomerated particles with well‐developed surfaces and diameters between 200 and 800 nm. For a predefined Y/Al ratio of 1:1, lower processing temperatures combined with longer heat treatments under stationary conditions resulted in a multiphase system, composed of YAP, YAG, and monoclinic yttrium aluminate (YAM) phases. However, a short heat treatment with a high heating rate (200 °C/min) at higher temperatures results in the formation of a kinetically favoured pure YAP hexagonal phase. On the other hand, for a predefined Y/Al ratio of 3:5, the generation of a thermodynamically favoured pure YAG phase has been confirmed, regardless of the applied heat‐treatment conditions. Although incomplete, Ce3+ introduction into the host matrix has been detected by XRPD and luminescence measurements.

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Photoluminescence of as an indication of crystal structure and particle size in nanoparticles synthesized by flame spray pyrolysis

Cited by 116 publications

References 38 publications

Nanophosphor Coatings: Technology and Applications, Opportunities and Challenges

Nanophosphor Coatings: Technology and Applications, Opportunities and Challenges

ζ-Potential analyses using micro-electrical field flow fractionation with fluorescent nanoparticles

Synthesis of Cerium‐Activated Yttrium Aluminate Based Fine Phosphors by an Aerosol Route

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