Visible and infrared luminescence properties of Er{sup 3+}-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.01.001· OSTI ID:21494238

Ting, Chu-Chi ^[1]; Chiu, Yi-Shan; Chang, Chia-Wei; Chuang, Liang-Chih ^[1]

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1. Graduate Institute of Opto-Mechatronics Engineering, National Chung Cheng University, 168 University Rd., Min-Hsiung, Chia-Yi, Taiwan, ROC (China)

Er{sup 3+}-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals were fabricated by the sol-gel method. While the annealing temperature exceeds 757 {sup o}C, amorphous pyrochlore phase Er{sub x}Y{sub 2-x}Ti{sub 2}O{sub 7} transfers to well-crystallized nanocrystals, and the average crystal size increases from {approx}70 to {approx}180 nm under 800-1000 {sup o}C/1 h annealing. Er{sub x}Y{sub 2-x}Ti{sub 2}O{sub 7} nanocrystals absorbing 980 nm photons can produce the upconversion (526, 547, and 660 nm; {sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2}, and {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2}, respectively) and Stokes (1528 nm; {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}) photoluminescence (PL). The infrared PL decay curve is single-exponential for Er{sup 3+} (5 mol%)-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals but slightly nonexponential for Er{sup 3+} (10 mol%)-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals. For 5 and 10 mol% doping concentrations, the mechanism of up-converted green light is the two-photon excited-state absorption. Much stronger intensity of red light relative to green light was observed for the sample with 10 mol% dopant. This phenomenon can be attributed to the reduced distance between Er{sup 3+}-Er{sup 3+} ions, resulting in the enhancement of the energy-transfer upconversion and cross-relaxation mechanisms. -- Graphical Abstract: Emission fluorescence spectra of the Er{sup 3+} (3, 5, 7, or 10 mol%)-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals annealed at 800 {sup o}C for 1 h under 980 nm pumping. The Er{sup 3+}-doped Y{sub 2}Ti{sub 2}O{sub 7} nanocrystals absorbing 980 nm photons can produce the upconversion (526, 547, and 660 nm; {sup 2}H{sub 11/2}{yields}{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}{yields}{sup 4}I{sub 15/2}, and {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2}, respectively) and Stokes (1528 nm; {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2}) photoluminescence. Display Omitted Research highlights: {yields} Er{sub 0.05}Y{sub 0.95}Ti{sub 2}O{sub 7} nanocrystals annealed at 800 {sup o}C exhibit the crystalline pyrochlore structure. {yields} Er{sub 0.05}Y{sub 0.95}Ti{sub 2}O{sub 7} nanocrystals possess the maximum upconversion and Stokes PL intensities. {yields} The upconversion mechanism of Er{sub 0.05}Y{sub 0.95}Ti{sub 2}O{sub 7} are the two-photon excited-state absorption.

• OSTI ID: 21494238
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 3; Other Information: DOI: 10.1016/j.jssc.2011.01.001; PII: S0022-4596(11)00002-8; 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
ABSORPTION
ANNEALING
DOPED MATERIALS
ERBIUM IONS
FLUORESCENCE SPECTROSCOPY
NANOSTRUCTURES
PHOTOLUMINESCENCE
PYROCHLORE
SOL-GEL PROCESS
TEMPERATURE RANGE 0400-1000 K
TITANATES
VISIBLE RADIATION
YTTRIUM COMPOUNDS
CHARGED PARTICLES
ELECTROMAGNETIC RADIATION
EMISSION
EMISSION SPECTROSCOPY
HEAT TREATMENTS
IONS
LUMINESCENCE
MATERIALS
MINERALS
OXYGEN COMPOUNDS
PHOTON EMISSION
RADIATIONS
SORPTION
SPECTROSCOPY
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS