Perovskite-type SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} compounds: Synthesis, crystal structure and optical properties

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.02.017· OSTI ID:21494245

Maegli, Alexandra ^[1]; Yoon, Songhak ^[1]; Otal, Eugenio ^[1]; Karvonen, Lassi ^[1]; Mandaliev, Peter ^[1]; Weidenkaff, Anke ^[1]

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1. Empa - Swiss Federal Laboratories for Materials Science and Technology, Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland)

The synthesis, crystal structure, thermal stability and absorbance spectra of perovskite-type oxynitrides with the general formula SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} (x=0.05, 0.10, 0.20, 0.50, 0.80, 0.90, 0.95) have been investigated. Oxide samples were prepared by a polymerized complex synthesis route and post-treated under ammonia at 850 {sup o}C for 24 h to substitute nitrogen for oxygen. Synchrotron X-ray powder diffraction (XRD) evidenced that the mixed oxide phases were all transformed into oxynitrides with perovskite-type structure during a thermal ammonolysis. SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} with compositions x{<=}0.80 crystallized in a cubic and samples with x{>=}0.90 in a tetragonal structure. The Rietveld refinement indicated a continuous enlargement of the lattice parameters towards higher niobium content of the samples. Thermogravimetric analysis (TGA) and hotgas extraction revealed the dependence of the nitrogen incorporation upon the degree of niobium substitution. It showed that more nitrogen was detected in the samples with higher niobium content. Furthermore, TGA disclosed stability for all oxynitrides at T{<=}400 {sup o}C. Diffuse reflectance spectroscopy indicated a continuous decrease of the band gap's width from 3.24 eV (SrTi{sub 0.95}Nb{sub 0.05} (O,N){sub 3}) to 1.82 eV (SrTi{sub 0.05}Nb{sub 0.95}(O,N){sub 3}) caused by the increasing amount of nitrogen towards the latter composition. -- Graphical Abstract: The system SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} is described and the changes in crystal structure, nitrogen content and width of the band gap are discussed. Display Omitted Research highlights: {yields} Synthesis of SrTi{sub 1-x}Nb{sub x}(O,N){sub 3} perovskite-type oxynitrides via thermal ammonolysis. {yields} Co-substitution of Nb{sup 5+} enabled to adjust the amount nitrogen insertion. {yields} Tuning of the optical band gap through nitrogen.{yields} Changes of crystal structure from cubic to tetragonal with increasing niobium content.

• OSTI ID: 21494245
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 4; Other Information: DOI: 10.1016/j.jssc.2011.02.017; PII: S0022-4596(11)00071-5; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AMMONIA
AMMONOLYSIS
CRYSTAL STRUCTURE
EV RANGE 01-10
LATTICE PARAMETERS
NIOBIUM COMPOUNDS
NIOBIUM IONS
NITRIDES
OPTICAL PROPERTIES
OXIDES
PEROVSKITE
SPECTRA
SPECTROSCOPY
STRONTIUM COMPOUNDS
SYNTHESIS
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMAL GRAVIMETRIC ANALYSIS
TITANIUM COMPOUNDS
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
COHERENT SCATTERING
DECOMPOSITION
DIFFRACTION
ENERGY RANGE
EV RANGE
GRAVIMETRIC ANALYSIS
HYDRIDES
HYDROGEN COMPOUNDS
IONS
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXIDE MINERALS
OXYGEN COMPOUNDS
PEROVSKITES
PHYSICAL PROPERTIES
PNICTIDES
QUANTITATIVE CHEMICAL ANALYSIS
REFRACTORY METAL COMPOUNDS
SCATTERING
SOLVOLYSIS
TEMPERATURE RANGE
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS