Bai Cheng Normal College

Baicheng, China

Bai Cheng Normal College

Baicheng, China

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Fu C.-B.,Tong Hua Normal College | Dong H.-J.,Bai Cheng Normal College | Liu C.-Y.,Tong Hua Normal College | Wang Y.-P.,Tong Hua Normal College
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2010

Series of green CaAl2O4:Tb3+ phosphors were first prepared by the Self-Propagating Combustion Synthesis (SPCS) methods. The unit cell of CaAl2O4:Tb3+ was confirmed monoclinic system with a space group P21/n by XRD analysis. Lattice constant refinement was a = 8.6831Å, b = 8.0728 Å, c = 15.1890 Å, β = 90.1647°, Z = 12. The completely precise peaks were observed in surprise from excitation and emission spectra. Rare excitation absorption of Tb3+ coming from 4f8→4f75d1 appeared in excitation spectra at 220-320nm. Emission spectra indicated that emission peaks were attributed to 5D4→7FJ (J = 6, 5, 4, 3, 2, 1, 0) at 500nm-700nm and 5D3→7FJ at 380nm-500nm. Vibration feature of products were investigated by FT-IR spectra. SEM revealed products had smooth surface, the better crystallization.


Zhang X.-Y.,Bai Cheng Normal College | Dong H.-J.,Bai Cheng Normal College | Mei Z.-M.,Bai Cheng Normal College
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2010

Series of high-purity CaAl2O4:Sm3+ phosphors were first successfully prepared by the Self-Propagating Combustion Synthesis (SPCS) methods. The unit cell of CaAl2O4:Sm3+ was confirmed monoclinic system with a space group P21/n by XRD analysis. Lattice constant refinement was a = 0.8699nm, b = 0.8212 nm, c = 1.5207nm, β = 90.1584°, Z=12. Emission peaks attributed to 4G5/2→6HJ (J = 5/2, 7/2, 9/2, 11/2) transitions at 568nm, 603nm, 655nm and 715nm, respectively, and Sm3+ ions mainly took up symmetry center lattice. Excitation peaks belonged to f→f configuration transition absorption of at 406nm, 379nm, 367nm and 349nm, which maybe attributed to 6H5/2→(4F7/2, 4L13/2), (4D1/2, 6P7/2), 4F9/2, 4K15/2, respectively. Vibration feature of products was investigated by FT-IR spectra. SEM revealed products had smooth surface, the better crystallization.


Composite CaAl 2O 4-2CaAl 4O 7: Re 3+ (Re 3+ = Tb 3+, Sm 3+) phosphors were prepared by the SPCS technique, which were studied via XRD, SEM, FT-IR spectra and luminescent spectra. The results show that the crystal lattice structure of them needs slight distortion to improve luminescence properties. They exhibit wider near-UV excitation band around 380 nm. Upon exciting with 380 nm, CaAl 2O 4-2CaAl 4O 7: Tb 3+ shows a strong green-light at 548 nm corresponding to a 5D 4 → 7F 5 transition of Tb 3+ ions, and CaAl 2O 4-2CaAl 4O 7: Sm 3+ presents strong red-light at 604 nm corresponding to a 4G 5/2 → 6H 7/2 transition of Sm 3+ ions. The product fired at 900 oC exhibit high quality crystallinity and with a size of that is approximately 1-3 μm. All the above characteristics of the products are beneficial for phosphors for white LEDs.


Dong H.J.,Bai Cheng Normal College
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2011

Composite CaAl 2O 4-2CaAl 4O 7:Eu 3+ phosphor is prepared by the SPCS technique. The study results of XRD and FT-IR spectrum show that crystal lattice structure of that engenders slight distortion to improve luminescence properties. Luminescence spectrum indicates that CaAl 2O 4-2CaAl 4O 7:Eu 3+ shows strong red-light at 618 nm corresponding to electric dipole transition 5D 0- 7F 2 of Eu 3+ ions, upon exciting with 382 nm. SEM micrographs reveal that the products fired at 900 °C exhibit high quality crystallinity and the size of that is approximately 1-3 μm. All above characteristics of the CaAl 2O 4-2CaAl 4O 7:Eu 3+ is beneficial to phosphors applying to white LEDs.

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