Luminescent nanocrystals in the rare-earth niobate–zirconia system formed via hydrothermal method

Journal Article · Thu Aug 15 04:00:00 EDT 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.06.016· OSTI ID:22280724

Hirano, Masanori; Dozono, Hayato

Luminescent nanocrystals based on the rare-earth niobates (Ln{sub 3}NbO{sub 7}, Ln=Y, Eu) and zirconia (ZrO{sub 2}) that were composed of 50 mol% Ln{sub 3}NbO{sub 7} and 50 mol% ZrO{sub 2}, were hydrothermally formed as cubic phase under weakly basic conditions at 240 °C. The lattice parameter of the as-prepared nanoparticles corresponding to the composition of Y{sub 3−x}Eu{sub x}NbO{sub 7}–4ZrO{sub 2} that was estimated as a single phase of cubic gradually increased as the content of europium x increased. The existence of small absorbance peaks at 395 and 466 nm corresponding to the Eu{sup 3+7}F{sub 0}→{sup 5}L{sub 6}, and {sup 7}F{sub 0}→{sup 5}D{sub 2} excitation transition, respectively, was clearly observed in the diffuse reflectance spectra of the as-prepared samples containing europium. The optical band gap of the as-prepared samples was in the range from 3.5 to 3.7 eV. The photoluminescence spectra of the as-prepared nanocrystals containing europium showed orange and red luminescences with main peaks at 590 and 610 nm, corresponding to {sup 5}D{sub 0}→{sup 7}F{sub 1} and {sup 5}D{sub 0}→{sup 7}F{sub 2} transitions of Eu{sup 3+}, respectively, under excitation at 395 nm Xe lamp. The emission intensity corresponding to {sup 5}D{sub 0}→{sup 7}F{sub 2} transition increased as heat-treatment temperature rose from 800 to 1200 °C. - Graphical abstract: This graphical abstract shows the excitation and emission spectra and a transmission electron microscopy image of nanocrystals (with composition based on the rare-earth niobates (Ln{sub 3}NbO{sub 7}, Ln=Y, Eu) and zirconia (ZrO{sub 2}) that were composed of 50 mol% Ln{sub 3}NbO{sub 7} and 50 mol% ZrO{sub 2}) formed via hydrothermal route. Display Omitted - Highlights: • Nanocrystals composed of 50 mol% Y{sub 3−x}Eu{sub x}NbO{sub 7} and 50 mol% ZrO{sub 2} was directly formed. • The nanocrystals were hydrothermally formed under weakly basic conditions at 240 °C. • The Y{sub 3}NbO{sub 7} showed an UV-blue and broad-band emission under excitation at 240 nm. • The emission is originated from the niobate octahedral group [NbO{sub 6}]{sup 7−}. • The nanocrystals showed orange and red luminescences ({sup 5}D{sub 0}→{sup 7}F{sub 1} and {sup 5}D{sub 0}→{sup 7}F{sub 2} , Eu{sup 3+})

• OSTI ID: 22280724
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 204; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
77 NANOSCIENCE AND NANOTECHNOLOGY
EMISSION SPECTRA
EUROPIUM
EUROPIUM IONS
EXCITATION
HEAT TREATMENTS
HYDROTHERMAL SYNTHESIS
LATTICE PARAMETERS
NANOSTRUCTURES
NIOBATES
PARTICLES
PEAKS
PHOTOLUMINESCENCE
TRANSMISSION ELECTRON MICROSCOPY
ZIRCONIUM OXIDES