Structural investigation and luminescence of nanocrystalline lanthanide doped NaNbO{sub 3} and Na{sub 0.5}K{sub 0.5}NbO{sub 3}

Journal Article · Sat Dec 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2012.08.003· OSTI ID:22149903

Pin, Sonia ^[1]; Piccinelli, Fabio ^[2]; Upendra Kumar, Kagola ^[3]; Enzo, Stefano ^[4]; Ghigna, Paolo ^[5]; Cannas, Carla; Musinu, Anna ^[6]; Mariotto, Gino ^[7]; Bettinelli, Marco ^[2]; Speghini, Adolfo ^[2]

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1. Paul Scherrer Institute, General Energy Research (ENE), Laboratory for Bioenergy and Catalysis, CH-5232 Villigen PSI (Switzerland)
2. Dipartimento di Biotecnologie, Universita di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37134 Verona (Italy)
3. Grupo de Fotonica e Fluidos Complexos, Instituto de Fisica, Universidade Federal de Alagoas (UFAL), Maceio-AL (Brazil)
4. Dipartimento di Chimica, Universita di Sassari, 07100 Sassari (Italy)
5. Dipartimento di Chimica, Universita di Pavia, V.le Taramelli 16, I-27100 Pavia (Italy)
6. Dipartimento di Scienze Chimiche, Universita di Cagliari, Cittadella Universitaria Monserrato, I-09042 Cagliari (Italy)
7. Dipartimento di Informatica, Universita di Verona, Strada Le Grazie 15, I-37134 Verona (Italy)

Nd{sup 3+} and Eu{sup 3+} doped NaNbO{sub 3} and Na{sub 0.5}K{sub 0.5}NbO{sub 3} nanostructured multiferroics (nanoparticles or nanorods) were prepared by a sol-gel route. X-Ray powder diffraction results evidence that the sodium and mixed sodium-potassium niobates show orthorhombic (Pmc2{sub 1} space group), and monoclinic structure (Pm space group), respectively, confirmed by the Raman spectra. The local structure around the trivalent lanthanides was investigated with Extended X-ray Absorption Fine Structure spectroscopy at the Ln-K edge and luminescence spectroscopy. The Ln{sup 3+} ions enter the structure by substituting the alkali metals, with a 12-fold oxygen coordination, and inducing a large amount of static disorder. The visible emission bands of the Eu{sup 3+} ions indicate that multiple sites exist for the lanthanide ions, in agreement with the EXAFS results showing the largest amount of static disorder in these samples. A possible indication of clustering of oxygen vacancies around the Ln{sub Na} Double-Prime defect is obtained by VBS calculations. - Graphical Abstract: Ln{sup 3+} doped NaNbO{sub 3} and Na{sub 0.5}K{sub 0.5}NbO{sub 3} nanoparticles or nanorods can be prepared by a simple sol-gel procedure. The synergy of X-ray diffraction, EXAFS and luminescence spectroscopy gives important information on the Ln{sup 3+} local environment. Highlights: Black-Right-Pointing-Pointer Nd{sup 3+} and Eu{sup 3+} doped NaNbO{sub 3} and Na{sub 0.5}K{sub 0.5}NbO{sub 3} nanoparticles or nanorods are prepared by sol-gel. Black-Right-Pointing-Pointer EXAFS indicates that the Ln{sup 3+} ions substitutes the Na{sup +} and K{sup +} ions, inducing a large amount of static disorder. Black-Right-Pointing-Pointer The visible emission bands of the Eu{sup 3+} ions confirm that multiple sites exist for the lanthanide ions.

• OSTI ID: 22149903
• Journal Information: Journal of Solid State Chemistry, Vol. 196, Issue Complete; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
CRYSTALS
DOPED MATERIALS
EUROPIUM IONS
LUMINESCENCE
NANOSTRUCTURES
NEODYMIUM IONS
ORTHORHOMBIC LATTICES
POTASSIUM IONS
RAMAN SPECTRA
RARE EARTHS
SODIUM
SODIUM IONS
SOL-GEL PROCESS
SPACE GROUPS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY