Publication Date:
2011-08-06
Description:
Rare earth ions ( Tb 3+ , Eu 3+ , Yb 3+ , Tm 3+ , Er 3+ , and Ho 3+ )-doped SrR 2 O 4 (R = Y and Gd ) were prepared by solid-state reaction, and their optical properties were investigated. Upon VUV–UV excitation, the SrY 1.99 O 4 :0.01 Tb 3+ exhibits a typical green emission of Tb 3+ with the dominant peak located at 543 nm. In the excitation spectrum of SrY 1.99 O 4 :0.01 Tb 3+ monitored at 543 nm, the f – d transition of Tb 3+ is observed and identified to lie in the much lower energy region compared with many other Tb 3+ -doped phosphors, which can be interpreted by a strong crystal field in SrY 2 O 4 structure. Upon X-ray excitation, SrY 1.99 O 4 :0.01 Eu 3+ displays an intense red fluorescence, whose strongest emission peak is situated at 611 nm, ascribed to 5 D 0 – 7 F 2 transition of Eu 3+ . Under 980 nm laser excitation, blue, green, and yellow emissions have been achieved in Yb 3+ – Tm 3+ , Yb 3+ – Er 3+ , and Yb 3+ – Ho 3+ co-doped SrGd 2 O 4 , respectively. An obvious intensity ratio enhancement of green emission to red one of Er 3+ was observed in Yb 3+ – Tm 3+ – Er 3+ tridoped SrGd 2 O 4 relative to Yb 3+ – Er 3+ co-doped samples, and the possible reason has been elucidated by a cross-relaxation process between Tm 3+ and Er 3+ . Laser power dependence of the up-converted emissions and the energy level diagrams were studied to understand the upconversion mechanisms.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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