Preparation of nonaggregated Y<sub>2</sub>O<sub>3</sub> : Eu phosphor particles by spray pyrolysis method

Kang, Yun Chan; Park, Seung Bin; Lenggoro, I. Wuled; Okuyama, Kikuo

doi:10.1557/jmr.1999.0349

Cited by 98 publications

(76 citation statements)

References 11 publications

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“…4(a). This value is considerably higher than that of sub micron phosphor prepared by the spray pyrolysis of metal nitrate precursors, 4) even though spray pyrolysis operated at higher temperatures (above 1400 C) and produced particles of larger sizes (in submicrometer). Most of the previous liter atures on the synthesis of Y 2 O 3 :Eu 3{ particles do not provide the comparison with the commercial phosphor.…”

Section: Results and Discussion Fesem Pictures Shown Inmentioning

confidence: 76%

“…spray pyrolysis, which has the peak at Eu/Y 0.06 mol/mol. 4) A reduction in the intensity when Eu/Y 0.07 mol/mol might be understood in terms of concentration quenching.…”

Section: Results and Discussion Fesem Pictures Shown Inmentioning

confidence: 99%

“…1),2) Convention ally, a few micrometer sized phosphor particles are pre pared via a breakdown route, such as solidstate synthesis. There have been a number attempts to synthesis submicron order or sub100 nm of Y 2 O 3 :Eu 3{ phosphors particles by a variety of methods, including gas phase, 3) spray pyrolysis, 4), 5) and wetchemical routes. 6)10) However, the challenge is to de velop a fast method, where the produced ne (submicron and sub100 nm) phosphor particles with highly crystallinity, and emitting a high luminescence intensity.…”

Section: Introductionmentioning

confidence: 99%

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Novel Processing for Softly Agglomerated Luminescent Y2O3: Eu3+ Nanoparticles Using Polymeric Precursors

Abdullah

Lenggoro

Xia

et al. 2005

J. Ceram. Soc. Japan

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Synthesis of europium ion doped yttrium oxide (Y 2 O 3 :Eu 3{ ) phosphor nanoparticles using a relatively high molecular weight polyethylene glycol is reported. Y 2 O 3 : Eu 3{ materials could be prepared by simply heating in air provided that, watersoluble polymer be added into solutions containing metal nitrates. The polymer was ex pected to form carbonaceous materials around the produced primary particles to reduce the tendency of those particles to agglomerate. The carbonaceous materials could be removed by heating at higher temperatures, resulting in softlyagglomerated particles in the size range of 20100 nm. The eect of synthesis parameters on particle morphology, crystallinity, and photoluminescence properties was investigated.

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Section: Results and Discussion Fesem Pictures Shown Inmentioning

confidence: 76%

“…spray pyrolysis, which has the peak at Eu/Y 0.06 mol/mol. 4) A reduction in the intensity when Eu/Y 0.07 mol/mol might be understood in terms of concentration quenching.…”

Section: Results and Discussion Fesem Pictures Shown Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel Processing for Softly Agglomerated Luminescent Y2O3: Eu3+ Nanoparticles Using Polymeric Precursors

Abdullah

Lenggoro

Xia

et al. 2005

J. Ceram. Soc. Japan

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“…Although they also found a second Gaussian profile at the high energy side of the CT-band, the absorption of this second band is low and deconvolution has almost no effect on the E CT . As already mentioned in the introduction, Kang et al 5 a much smaller spread; this spread is assumed to be mainly caused by small calibration errors of the spectrometers of about 1 nm. Since we have synthesized and annealed all samples in exactly the same way leading to identical particle size and surface morphology as shown in Figure 1, it is assumed that we have ruled out the afore mentioned source of spread: in other words, the observed redshift of the E CT is an intrinsic property of (Y 1−x Eu x ) 2 O 3 upon increasing x.…”

Section: Figsmentioning

confidence: 93%

“…2-10 Upon increasing the Eu 3+ concentration between 1 and 15 Mol % a redshift of the E CT of about 6 nm has been observed, [2][3][4] whereas Kang et al 5 did not observe a change of E CT in increasing the Eu 3+ dope from 2 to 10 Mol %. Some peculiar observations were reported on the effect of the particle size of Y 2 O 3 :Eu 3+ .…”

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confidence: 99%

Red Shift of CT-Band in Cubic Y₂O₃:Eu³⁺upon Increasing the Eu³⁺Concentration

Engelsen

Ireland

Dhillon

et al. 2016

ECS J. Solid State Sci. Technol.

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In this article we describe the redshift of the charge transfer band of nanosized cubic (Y 1−x Eu x ) 2 O 3 upon increasing the Eu 3+ concentration. This redshift amounts to 0.43 eV (25 nm) in going from 0.1 Mol % Eu 3+ to 100 Mol % (which is pure Eu 2 O 3 ). The charge transfer band consists of two broad sub-bands; both shift almost parallel with the Eu 3+ concentration and are related to the two symmetry sites for the cation, C 2 and C 3i , in the bixbyite-type lattice. The area ratio of the bands is 3:1 and is the first direct evidence for the population of the two lattice sites by the Eu 3+ cations being in accord with the crystal structure ratio. A model is presented that quantitatively describes the redshift of the charge transfer band of (Y The red luminescent phosphor Y 2 O 3 :Eu 3+ has been studied extensively, because of its rather high efficiency and high stability to electron bombardment, UV-irradiation and ion bombardment. These attributes led cubic Y 2 O 3 :Eu 3+ to be widely employed in cathode ray tubes (projection tubes) and it is still used in fluorescent lamps. Many properties of this phosphor have been studied by photoluminescence (PL) and cathodoluminescence (CL) spectrometry and have been well documented, because of its industrial applications. Notwithstanding the extensive literature on Y 2 O 3 :Eu 3+ , voids still exist in our knowledge on this phosphor. One of these voids is related to the position of the charge transfer (CT) band in the excitation spectrum, although this subject has been widely studied. In the present study we shall focus on the position of the CT-band, which is located at 253 nm in Y 2 O 3 when doped with 0.1 Mol % Eu 3+ . 1 The wavelength of the maximum of the CT-band in Y 2 O 3 :Eu 3+ , indicated by the E CT in this study and expressed in nanometers (nm) or electron-volts (eV) depends on the concentration of the Eu 3+ dopant and the size of the phosphor particles.2-10 Upon increasing the Eu 3+ concentration between 1 and 15 Mol % a redshift of the E CT of about 6 nm has been observed, [2][3][4] whereas Kang et al. 5 did not observe a change of E CT in increasing the Eu 3+ dope from 2 to 10 Mol %. Some peculiar observations were reported on the effect of the particle size of Y 2 O 3 :Eu 3+ . Igarashi et al. 6 reported a blueshift of the E CT of 6 nm in reducing the particle size from 2.1 μm to 56 nm; Fu et al.7 measured a blueshift of 5 nm in reducing the particle size from 2.1 μm down to 10 nm. The opposite trend was found by others. Jia et al.8 measured a redshift of the E CT of 6 nm upon particle size reduction from 2-3 μm to 7 nm. Shang et al. 9 and Zhang et al. 10 reported large red shifts, 11 nm and 7 nm, in reducing the size of Y 2 O 3 :Eu 3+ nanoparticles from 40 nm to 9 nm and from 40 nm to 5 nm respectively. Semiconductor particles are expected to show a blueshift of their absorption peaks in reducing the particle size from 15 to 5 nm because of quantum confinement.11 The observed opposite trend indicates that quantum confinement cannot explain the reported ...

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Modeling of spray pyrolysis—why are the synthesized Y₂O₃ microparticles hollow?

et al. 2007

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in Wiley InterScience (www.interscience.wiley.com).There are some major advantages to be gained in processing micronic europium doped yttrium oxide Y 2 O 3 particles for phosphor applications using spray pyrolysis. To better understand the influence of the operating conditions and also why hollow particles are formed, a complete one-dimensional modeling of the pure evaporation then evaporation/precipitation steps of micronic water/Y(NO 3 ) 3 droplets has been performed. Among the main results, it appears that no concentration gradient exists inside droplets during the pure evaporation stage and that the evaporation/precipitation stage, occurring in less than 10 23 s, leads to compact particles theoretically formed of a coherent porous medium of Y(NO 3 ) 3 Á5H 2 O. But the analysis of phenomena occurring during the thermolysis step between 95 and 3008C has revealed that a partial liquefaction of the hydrated yttrium nitrate occurs with concomitant release of gas. As a consequence, a crust of lightly hydrated yttrium nitrate probably appears, followed by particle inflation and leading to the formation of broken hollow particles.

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Preparation of nonaggregated Y₂O₃ : Eu phosphor particles by spray pyrolysis method

Cited by 98 publications

References 11 publications

Novel Processing for Softly Agglomerated Luminescent Y2O3: Eu3+ Nanoparticles Using Polymeric Precursors

Novel Processing for Softly Agglomerated Luminescent Y2O3: Eu3+ Nanoparticles Using Polymeric Precursors

Red Shift of CT-Band in Cubic Y₂O₃:Eu³⁺upon Increasing the Eu³⁺Concentration

Modeling of spray pyrolysis—why are the synthesized Y₂O₃ microparticles hollow?

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Preparation of nonaggregated Y2O3 : Eu phosphor particles by spray pyrolysis method

Cited by 98 publications

References 11 publications

Novel Processing for Softly Agglomerated Luminescent Y2O3: Eu3+ Nanoparticles Using Polymeric Precursors

Novel Processing for Softly Agglomerated Luminescent Y2O3: Eu3+ Nanoparticles Using Polymeric Precursors

Red Shift of CT-Band in Cubic Y2O3:Eu3+upon Increasing the Eu3+Concentration

Modeling of spray pyrolysis—why are the synthesized Y2O3 microparticles hollow?

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Preparation of nonaggregated Y₂O₃ : Eu phosphor particles by spray pyrolysis method

Red Shift of CT-Band in Cubic Y₂O₃:Eu³⁺upon Increasing the Eu³⁺Concentration

Modeling of spray pyrolysis—why are the synthesized Y₂O₃ microparticles hollow?