Luminescence response and CL degradation of combustion synthesized spherical SiO{sub 2}:Ce nanophosphor
- Department of Physics, University of the Free State, P. O. Box 339, Bloemfontein ZA9300 (South Africa)
Highlights: Black-Right-Pointing-Pointer A simple combustion reaction and post annealing process were adopted to generate SiO{sub 2}:Ce nanocrystalline phosphor. Black-Right-Pointing-Pointer The annealing under reductive carbon-oxygen environment rendered a partial conversion of Ce{sup 4+} to Ce{sup 3+} ions. Black-Right-Pointing-Pointer Excellent spectroscopic behavior of SiO{sub 2}:Ce{sup 3+} under various excitation stimuli is evaluated and discussed. Black-Right-Pointing-Pointer The long term columbic aging and luminescence output are monitored under a continuous 2 kV accelerated electron flux. Black-Right-Pointing-Pointer Simultaneous presence of Ce{sup 3+} and Ce{sup 4+} states in SiO{sub 2} host has been resolved using X-ray photoelectron spectroscopy (XPS). Black-Right-Pointing-Pointer The formation of a sub-stoichiometric SiO{sub x(x<2)} layer is responsible for CL degradation. -- Abstract: This study was aimed to systematically investigate the luminescence response of SiO{sub 2}:Ce{sup 3+} nanophosphors with different excitation sources. The powders were synthesized by using an urea assisted combustion method. SiO{sub 2}:Ce{sub 1m%} samples were also annealed at 1000 Degree-Sign C for 1 h in a charcoal environment to reduce incidental Ce{sup 4+} to partial Ce{sup 3+} ions. High resolution transmission electron microscopy (HRTEM) images of the as synthesized and annealed powder samples confirmed that the particles were spherical and in the size range of 3-8 nm in diameter. X-ray diffraction (XRD) and electron dispersion spectroscopy (EDS) results showed that the SiO{sub 2} was crystalline and pure. Diffused reflectance, photoluminescence (PL) and cathodoluminescence (CL) results of the SiO{sub 2}:Ce{sup 3+} samples were obtained and compared with each other. The CL degradation and the surface reactions on the surface of the SiO{sub 2}:Ce{sup 3+} were studied with X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A clear improvement in the chemical stability of the SiO{sub 2}:Ce{sup 3+} annealed at 1000 Degree-Sign C were obtained.
- OSTI ID:
- 22212350
- Journal Information:
- Materials Research Bulletin, Vol. 46, Issue 12; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
77 NANOSCIENCE AND NANOTECHNOLOGY
ANNEALING
AUGER ELECTRON SPECTROSCOPY
CATHODOLUMINESCENCE
CERIUM IONS
CRYSTALS
NANOSTRUCTURES
PHOTOLUMINESCENCE
SILICA
SILICON OXIDES
SURFACE PROPERTIES
SURFACES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY