Tunable silica shell and its modification on photoluminescent properties of Y{sub 2}O{sub 3}:Eu{sup 3+}-SiO{sub 2} nanocomposites
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)
The core-shell rare earth (RE) doped nanophosphors are attracting current interests owing to their potential application in bio-images. Understanding the modification of core-shell structure on photoluminescent (PL) properties of RE ions is important in obtaining efficient nanophosphors. In this paper, Y{sub 2}O{sub 3}:Eu{sup 3+}-SiO{sub 2} composites with fixed cubic Y{sub 2}O{sub 3}:Eu{sup 3+} core ({approx}80 nm) and controllable thickness of silica shell ({approx}3-21 nm) were synthesized via a modified Stoeber method and characterized by x-ray diffraction patterns, transmission electronic microscope images, and Fourier-transform infrared absorption spectra. The dependences of PL properties of Y{sub 2}O{sub 3}:Eu{sup 3+} on the thickness of the silica shell and excitation power density were systemically studied under charge transfer excitation (254 nm) and {sup 7}F{sub J}-{sup 5}D{sub 2} inner-shell excitation (460-486 nm). It is interesting to observe that under {sup 7}F{sub J}-{sup 5}D{sub 2} excitation the intensity ratio of {sup 5}D{sub 0}-{sup 7}F{sub 2}/{sup 5}D{sub 0}-{sup 7}F{sub J} (J {ne} 2) for Eu{sup 3+} increases considerably with the increase of shell thickness and decreases with the increasing excitation power density, which confirms the variation of long-scale radiative energy transfer (RET) among Eu{sup 3+} ions and redistribution of {sup 5}D{sub 0}-{sup 7}F{sub J}(J = 0-4) transitions. And more, the radiative decay time of {sup 5}D{sub 0}-{sup 7}F{sub J} as a function of shell thickness demonstrates an optimum, which are assigned to the co-impacts of effective refractive index (n{sub eff}) and RET among Eu{sup 3+} ions.
- OSTI ID:
- 22038890
- Journal Information:
- Journal of Applied Physics, Vol. 111, Issue 6; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
77 NANOSCIENCE AND NANOTECHNOLOGY
ABSORPTION SPECTRA
CHARGE EXCHANGE
COMPOSITE MATERIALS
DOPED MATERIALS
ENERGY TRANSFER
EUROPIUM IONS
FOURIER TRANSFORMATION
INFRARED SPECTRA
INNER-SHELL EXCITATION
NANOSTRUCTURES
PHOTOLUMINESCENCE
REFRACTIVE INDEX
RHENIUM IONS
SILICON OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
YTTRIUM OXIDES