Red nanofluorescent materials based on CaWO4:Eu3+ were prepared by the molten salt method. Spherical CaWO4 particles with a size of 100 nm to 200 nm monodisperse sizes were prepared using different types of calcium salts. The KCl was chosen as the molten salt, under the same other experimental parameters, the obtained CaWO4:Eu3+ particles were more uniform, the diffraction properties were better. With a molar ratio of 15 for molten salt and Calcium salt, more spherical CaWO4:Eu3+ particles were produced small and sand homogeneous size. Using different amount of molten salt, it was found that the larger the amount of molten salt, the weaker the fluorescence property. Finally, by comparing the products obtained by the molten salt method with the solid state reaction method, it is found that the luminescence intensity of the products is 20% higher than that obtained by the solid state reaction method.
Novel CaWO 4 :Eu 3+ , Mn 2+ red phosphor is synthesized by solid-state reaction method in air. CaWO 4 :Eu 3+ , Mn 2+ phosphor with excitation 268 and 394 nm emits red light with chromaticity coordinates (x = 0.6403, y = 0.3593). The strongest emission bands peaking at ∼615 nm is attributed to 5 D 0 → 7 F 2 of Eu 3+ ion. Strong excitation band peaking at ∼394 nm indicates that the phosphor may be excited by near UV (∼394 nm) chip. Emission intensity of CaWO 4 :Eu 3+ , Mn 2+ phosphor with excitation 268 nm is ∼2 times stronger than that of CaWO 4 :Eu 3+ phosphor owing to energy transfer between Eu 3+ ion and Mn 2+ ion. Energy transfer from WO 4 2 − group and Eu 3+ ion to Mn 2+ ion in CaWO 4 :Eu 3+ , Mn 2+ phosphor may be explained via luminescence properties. Luminous mechanism is analyzed by energy level diagrams of WO 4 2 − group, Mn 2+ and Eu 3+ ion. The paper content is helpful to develop and research other novel phosphors.
Xiaoqing Guo,Shuangju Song,Xue Jiang,Xue Wang,Jiahui Guo,Qingwei Song,Yuanyuan Han,Liyong Wang
Eu 3+ activated CaWO 4 (CWO) phosphors were prepared via a modified hydrothermal process. In present work, the phosphors illustrated enhanced emission properties by the assistance of poly acrylic acid (PAA). The phase structure, micromorphology, photoluminescence properties and luminescence enhancement mechanism of the as-prepared samples were investigated. The as-prepared PAA assisted samples exhibited significantly enhanced red emission peaking at 595 nm and emission intensity increased by about 8 times. The results indicated that CWO: Eu 3+ samples could be a potential candidate of red phosphor for white light-emitting diodes (WLEDs).
危险品化学品经营许可证（带存储）