白光LED用Ca8Mg(SiO4)4Cl2: Eu(上标 2+)，Dy(上标 3+)发光粉的发光性能

Calcium magnesium chlorosilicate [Ca8Mg (SiO4) 4Cl2] doped with Eu(superscript 2+) can be used as a kind of green phosphor for white-light LED because of its effective excitation under NUV light source and bright green emission. However, according to the current research, the relative brightness of this green phosphor had to be improved. In this paper, calcium magnesium chlorosilicate [Ca8Mg (SiO4) 4Cl2] green phosphors, doped with Eu(superscript 2+) or co-doped with Eu(superscript 2+) and Dy3(superscript 2+), were synthesized by high-temperature solid-state reaction in reducing atmosphere. The luminescent properties of these phosphors, as well as the interaction mechanism between Dy(superscript 3+) and Eu(superscript 2+), were investigated. The significant enhancement of Ca8Mg (SiO4) 4Cl2: Eu(superscript 2+) green emission was obtained by co-doping with Dy(superscript 3+), and the 505 nm emission intensity of Eu(superscript 2+) is increased by 12% with an optimum Dy(superscript 3+) content of 0.02. Funthermore, the concentration quenching process was also discovered, and the luminescent intensity of Ca8Mg (SiO4) 4Cl2: Eu(superscript 2+), Dy(superscript 2+) phosphor decreases with further increasing the concentration of Dy(superscript 3+). In this paper, It is suggested to be an energy transfer process between Dy(superscript 3+) and Eu(superscript 2+) on the basis of spectral characteristics of Dy(superscript 3+) and Eu(superscript 2+). On account of the relatively low intensity of Dy(superscript 3+) 4f-4f emission, the energy transfer could be radiation reabsorption process. On the other hand, the energy transfer mechanism might be ascribed to resonant transfer process, for the radiative lifetime of the 4f-4f forbidden electric-dipole transition of Dy(superscript 3+) is much longer than that of the 5d-4f transitions of Eu(superscript 2+). Thus, the most likely energy transfer mechanism between Dy(superscript 3+) and Eu(superscript 2+) can be attributed to nonradiative cross relaxation process.