A series of barium-tungstate-based phosphors doped with different concentrations of Dy<sup>3+</sup> were synthesized by solid-state reaction method. Photoluminescence properties and decay lifetime of Dy<...A series of barium-tungstate-based phosphors doped with different concentrations of Dy<sup>3+</sup> were synthesized by solid-state reaction method. Photoluminescence properties and decay lifetime of Dy<sup>3+</sup>-doped BaWO<sub>4</sub> samples were studied. The results indicated that luminescent properties of BaWO<sub>4</sub>:Dy<sup>3+</sup> depended on the Dy<sup>3+</sup> concentration, and the inner energy could transfer from to Dy<sup>3+</sup>. The quality of the light was checked by estimating CIE parameters, and the results showed that BaWO<sub>4</sub>:Dy<sup>3+</sup> was a potential candidate as blue-green luminescent materials in white LED because of its excellent emission spectrum excited by UV light.展开更多
The study of boron structure is fascinating because boron has various allotropes containing boron icosahedrons under pressure. Here, we propose a new boron structure(space group Fm3m) that is dynamically stable at 1.4...The study of boron structure is fascinating because boron has various allotropes containing boron icosahedrons under pressure. Here, we propose a new boron structure(space group Fm3m) that is dynamically stable at 1.4 tera-Pascal(TPa)using density functional theory and an evolutionary algorithm. The unit cell of this structure can be viewed as a structure with a boron atom embedded in the icosahedron. This structure behaves as a metal, and cannot be stable under ambient pressure. Furthermore, we found electrons gather in lattice interstices, which is similar to that of the semiconductor Na or Ca_(2)N-Ⅱ under high pressure. The discovery of this new structure expands our comprehension of high-pressure condensed matter and contributes to the further development of high-pressure science.展开更多
文摘A series of barium-tungstate-based phosphors doped with different concentrations of Dy<sup>3+</sup> were synthesized by solid-state reaction method. Photoluminescence properties and decay lifetime of Dy<sup>3+</sup>-doped BaWO<sub>4</sub> samples were studied. The results indicated that luminescent properties of BaWO<sub>4</sub>:Dy<sup>3+</sup> depended on the Dy<sup>3+</sup> concentration, and the inner energy could transfer from to Dy<sup>3+</sup>. The quality of the light was checked by estimating CIE parameters, and the results showed that BaWO<sub>4</sub>:Dy<sup>3+</sup> was a potential candidate as blue-green luminescent materials in white LED because of its excellent emission spectrum excited by UV light.
基金Project supported by the Guangdong Natural Science Foundation of China (Grant Nos. 2017B030306003 and 2019B1515120078)the National Natural Science Foundation of China (Grant No. 11804057)。
文摘The study of boron structure is fascinating because boron has various allotropes containing boron icosahedrons under pressure. Here, we propose a new boron structure(space group Fm3m) that is dynamically stable at 1.4 tera-Pascal(TPa)using density functional theory and an evolutionary algorithm. The unit cell of this structure can be viewed as a structure with a boron atom embedded in the icosahedron. This structure behaves as a metal, and cannot be stable under ambient pressure. Furthermore, we found electrons gather in lattice interstices, which is similar to that of the semiconductor Na or Ca_(2)N-Ⅱ under high pressure. The discovery of this new structure expands our comprehension of high-pressure condensed matter and contributes to the further development of high-pressure science.
