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1

Gd_{2}O_{3}:Eu^{3+}/PMMA Composite: Thermal and Luminescence Properties

100%

Antić Ž., Krsmanović R., Marinović-Cincović M., Dramićanin M.

Acta Physica Polonica A

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2010

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vol. 117

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issue 5

831-836

EN

In recent years there is an increasing interest in obtaining and investigating composite materials that comprise nanoparticles as fillers and polymers as matrix. Such composites may display combined features of both components, and sometimes even novel properties resulting from their mutual interactions. It is important that both unique size-dependent properties of nanoparticles and favorable properties of polymer material remain preserved in the composite. In this research we investigated the possibility of obtaining composite material using as polymer matrix poly (methyl methacrylate) - PMMA and Gd_{2}O_{3}:Eu^{3+} nanopowder as filler. Three samples, containing 1, 3 and 5 mass % of Gd_{2}O_{3}:Eu^{3+}, are prepared with a dispersion casting method. The composites exhibited characteristic red emission coming from the ^{5}D_{0} → ^{7}F_{2} transition of Eu^{3+} ion in Gd_{2}O_{3}:Eu^{3+}. The observed lifetime values, around 1.1 ms, are quite high and suggest successful encapsulation of dopant ions in polymer through gadolinium oxide host. Experimental intensity parameters, transition rates and quantum efficiency of the ^{5}D_{0} emission are calculated from emission spectra using Judd-Ofelt theory. Influence of Gd_{2}O_{3}:Eu^{3+} filler on the modification of glass transition and thermo-degradable properties of the polymer matrix is also investigated. Thermal analyses give evidence of unchanged thermal stability of polymer phase in the composites.

2

LaYO_{3}:Sm^{3+} Nanocrystalline Phosphor: Preparation and Emission Properties

88%

Đorđević V., Nikolić M., Antić Ž., Mitrić M., Dramićanin M.

Acta Physica Polonica A

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2011

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vol. 120

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issue 2

303-305

EN

Samarium doped LaYO_{3} nanocrystalline phosphor powders are obtained by polymer complex solution method. Stoichiometric quantities of La_{2}O_{3}, Y_{2}O_{3} and for dopant ions Sm_{2}O_{3} were dissolved in hot nitric acid. Polyethylene glycol was added in solutions in 1:1 mass ratio to corresponding metal nitrates to form gel. The gel is combusted and annealed at 800°C for two hours to form nanopowder samples. Crystalline structure and phase purity is checked by X-ray diffraction and show that this material is synthesized in cubic bixbyite type structure for the first time. Luminescence properties of Sm^{3+} doped LaYO_{3} exhibited characteristic orange-red emission coming from the intra-4f-shell ^{4}G_{5/2}→^{6}H_{J} electron transitions with emission decay of 1.5 ms. Energy level positions are derived from emission and excitation spectra.

3

Optical Properties of Y_2O_3:Eu^{3+} Red Emitting Phosphor Obtained via Spray Pyrolysis

88%

Antić Ž., Krsmanović R., Ðorđević V., Dramićanin T., Dramićanin M.

Acta Physica Polonica A

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2009

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vol. 116

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issue 4

622-624

EN

In the present work we explored the possibility of obtaining Y_2O_3:Eu^{3+} μm-size particles by an ultrasonic spray pyrolysis method. As-prepared sample constitutes of spherical, hollow particles with an average size of 1 to 2 μm. Pure, well crystalline, cubic Y_2O_3 is formed after additional thermal treatment at 800°C for 2 h. A detailed optical investigation has been done with photoluminescence measurements in the energy and time domains. Experimental intensity parameters, transition rates and quantum efficiency of the ^{5}D_0 emission are evaluated on the basis of Judd-Ofelt theory.

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3 Acta Physica Polonica A

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3 Antić Ž.

3 Dramićanin M.

2 Krsmanović R.

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1 Marinović-Cincović M.

1 Mitrić M.

1 Nikolić M.

1 Ðorđević V.

1 Đorđević V.

Gd_{2}O_{3}:Eu^{3+}/PMMA Composite: Thermal and Luminescence Properties

LaYO_{3}:Sm^{3+} Nanocrystalline Phosphor: Preparation and Emission Properties

Optical Properties of Y_2O_3:Eu^{3+} Red Emitting Phosphor Obtained via Spray Pyrolysis