CAJ | 학술논문

采用高温固相法合成了白光LED用Ca_8Mg(SiO_4)_4Cl_2:Eu和Ca_8Mg(SiO_4)_4Cl_2:Eu,Dy绿色发光粉.研究发现:共掺Dy可以明显地提高Ca_8Mg(SiO_4)_4Cl_2:Eu发光粉的发光性能,表明Dy~(3+)和Eu~(2+)之间存在着能量传递过程.当Dy~(3+)的最佳掺杂摩尔分数为0.02时,发光粉505 nm处绿光发射的强度约提高12%.通过对Dy~(3+)和Eu~(2+)光谱特性的分析,Dy~(3+)和Eu~(2+)之间的能量传递机制可归因于无辐射交叉弛豫.
채용고온고상법합성료백광LED용Ca_8Mg(SiO_4)_4Cl_2:Eu화Ca_8Mg(SiO_4)_4Cl_2:Eu,Dy록색발광분.연구발현:공참Dy가이명현지제고Ca_8Mg(SiO_4)_4Cl_2:Eu발광분적발광성능,표명Dy~(3+)화Eu~(2+)지간존재착능량전체과정.당Dy~(3+)적최가참잡마이분수위0.02시,발광분505 nm처록광발사적강도약제고12%.통과대Dy~(3+)화Eu~(2+)광보특성적분석,Dy~(3+)화Eu~(2+)지간적능량전체궤제가귀인우무복사교차이예.
Calcium magnesium chlorosilicate [Ca_8Mg(SiO_4)_4Cl_2] doped with Eu~(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 [Ca_8Mg(SiO_4)_4Cl_2] green phosphors, doped with Eu~(2+) or co-doped with Eu~(2+) and Dy~(3+), 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~(3+) and Eu~(2+), were investigated. The significant enhancement of Ca_8Mg(SiO_4)_4Cl_2:Eu~(2+) green emission was obtained by co-doping with Dy~(3+), and the 505 nm emission intensity of Eu~(2+) is increased by 12% with an optimum Dy~(3+) content of 0.02. Funthermore, the concentration quenching process was also discovered, and the luminescent intensity of Ca_8Mg (SiO_4)_4Cl_2:Eu~(2+), Dy~(2+) phosphor decreases with further increasing the concentration of Dy~(3+). In this paper, It is suggested to be an energy transfer process between Dy~(3+) and Eu~(2+) on the basis of spectral characteristics of Dy~(3+) and Eu~(2+). On account of the relatively low intensity of Dy~(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~(3+) is much longer than that of the 5d-4f transitions of Eu~(2+). Thus, the most likely energy transfer mechanism between Dy~(3+) and Eu~(2+) can be attributed to nonradiative cross relaxation process.