A new route for the hydrothermal synthesis of Eu doped tin oxide nanoparticles

D. Tarabasanu-Mihaila1*, L. Diamandescu1, M. Feder1, S. Constantinescu1, V.S. Teodorescu1, S. Georgescu2, A. Banuta1

1 National Institute of Materials Physics, P.O. BOX MG-7, Bucharest, Romania 2 National Institute of Laser Plasma & Radiation Physics, P.O. BOX MG-36, Bucharest, Romania

A new route for the hydrothermal synthesis of Eu doped tin oxide nanoparticles

D. Tarabasanu-Mihaila1*, L. Diamandescu1, M. Feder1, S. Constantinescu1, V.S. Teodorescu1, S. Georgescu2, A. Banuta1

1 National Institute of Materials Physics, P.O. BOX MG-7, Bucharest, Romania 2 National Institute of Laser Plasma & Radiation Physics, P.O. BOX MG-36, Bucharest, Romania

STATE OF THE ART AND OBJECTIVESTATE OF THE ART AND OBJECTIVE

EXPERIMENTALEXPERIMENTAL

TEM / EDX

LUMINESCENCE

CONCLUSION Eu doped SnO2 nanoscaled powders were obtained in an extended solubility range (up to ~20 at.% Eu) directly, by a new hydrothermal route at moderate temperature (250 C); The nanocrystalline Eu:SnO2 powders have the cassiterite structure (rutile type);

The mean particle size is ~ 3-5 nm for as resulted hydrothermal samples and ~ 5-10 nm for the calcinated powders;

Eu+3 ions can substitute for Sn4+ or can enter interstitially in the SnO2 nanostructure. At Eu/Sn concentration ratio = 1/1 (50 at % Eu), well crystallized cubic Eu2Sn2O7 (compound

of interest in high temperature catalytic application) has been obtained.

Acknowledgements. This work was prepared with the support of the Romanian Ministry of Education and Research, under the Core Program PN09-450102. *Corresponding author: doinat@infim.ro

MÖSSBAUER SPECTROSCOPY ON 151Eu

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A 10-a editie a Seminarului National de nanostiinta si nanotehnologie

18 mai 2011 Biblioteca Academiei Romane

• SnO2 is an attractive semiconductor, host lattice for optical active rare earths ions owing to its chemical stability and electronic and optical properties (wide band gap of 3.6 eV, high transparency in the visible light region).

• SnO2 based luminescent materials (phosphors) have been synthetized by various methods: sol-gel, radio-frecvency sputtering, microwave assisted-solvothermal route, coprecipitation etc. [1-3].

• Eu+3 ions exhibit an intense red light emission arising from 5D07Fj transition; Eu+3 doped SnO2 emits an unique reddish-orange color.

• The solubility limit of Eu+3 in SnO2 is low (0,5-8 at%) because of the difference in the ionic radius and chemical valence state of Eu+3 and Sn+4. At higher doping concentration, the excess of Eu+3 may seggregate on the nanoparticle surface as separated phases.

 This study reports on the new route for the hydrothermal synthesis of Eu:SnO2

nanocrystalline oxides, extending the solubility range to 20 at % Eu, together with the structural and morphological characterization of the obtained nanostructures.

Luminescence spectra for the hydrothermal sample 3 at % Eu: SnO2, as resulted (a) and after calcination at 650 °C (b).

References

1.E. A. Morais, L. V. A. Scalvi, A. Tabata, “Photoluminescence of Eu3+ Ion in SnO2 Obtained by Sol–Gel”, J. Mater. Sci., 43, 1 (2008) 345–349.

2. T. H. Moon, S. T. Hwang, D. R. Jung, “Hydroxyl-Quenching Effects on the Photoluminescence Properties of SnO2:Eu3+ Nanoparticles”, J. Phys. Chem. C,111,11 (2007) 4164–4167.

3. D.H. Park, Y.H. Cho, Y.R. Do, B.T. Ahn, “Characterization of Eu- Doped SnO2 Thin Films Deposited by Radio-Frequency Sputtering for a Transparent Conductive Phosphor Layer,” J.Electrochem. Soc.,153, 4 (2006) H63–H67 .

TEM images and EDX spectrum of the sample with 6 at % Eu; the atomic ratio Eu/Sn given by EDX: 5.9/94.1 ↔ 6.8/93.2.

Hydrothermal synthesis routeHydrothermal synthesis route

Mössbauer spectrum on 151Eu for the hydrothermal sample at 6 at % Eu: SnO2 (left) in comparison with Eu2O3 Mössbauer spectrum (right) showing the presence of many inequivalent Eu sites in the SnO2 structure.

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