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1. chinaXiv:201703.00563 [pdf]

Vibronic photoexcitation spectra of irradiated spinel MgOAl2O3(n=2) at low temperatures

Abu Zayed Mohammad Saliqur Rahman; Xingzhong Cao; Long Wei; Baoyi Wang; Shuaishuai Sun; Ye Tao; Qiu Xu
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

A vibronic photoexcitation band at approximately 230 nm was found at 13 K in reactor neutron- and electron-irradiated magnesiumaluminate spinel ( MgOAl2O3). Vibronic structure was found to be temperature dependent and became obscure at over 120K. Huang Rhys factor S and Debye Temperature D were estimated from the temperature dependence of the 230 nm band bycurve-fitting method using Debye approximation. Origin of the vibronic photoexcitation band was suggested as F center.

submitted time 2017-03-26 Hits1299Downloads783 Comment 0

2. chinaXiv:201703.00561 [pdf]

Luminescence properties of samarium-doped SiO2-Na2SO4 composite

Abu Zayed Mohammad Saliqur Rahman; Xingzhong Cao; Long Wei; Baoyi Wang; Haichen Wu
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

The comprehensive structural and luminescence study of Sm-doped SiO2-Na2SO4 composite materials are reported. The samples were synthesized by melt-mixing mixture of Na2SO4 and SmF3 into the SiO2 matrix at 1050 C for 30 min. X-ray di raction (XRD) pattern shows the characteristic structure of the SiO2 and addition of 20% Na2SO4:Sm has no e ect on the basic crystal structure of the SiO2. Scanning electron microscopy (SEM) shows the clear di erence in morphological structure between the composite and host SiO2. From photoexcitation (PE) spectra of the as-synthesized composite, the highest excitation e ciency was observed at 402 nm. The photoluminescence (PL) spectra of as-synthesized composite phosphors obtained under 402 nm excitation consist of five narrow emission bands with peaks at 563, 598, 644, 704 and 784 nm. These are assigned to the 4G5=2 ! 6HJ (J=5/2, 7/2, 9/2, 11/2 and 13/2, respectively) transitions within 4f5 electronic configuration of Sm3+. Highest luminescence intensity was observed with SiO2-10%Na2SO4:Sm.

submitted time 2017-03-26 Hits1303Downloads780 Comment 0

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