YAG:Ce,Tb磷光体中的能量传递现象

引言 Ce3+和Tb3+等稀土离子激活的YAG发光材料已引起人们的兴趣.我们对YAG:Ce,Tb磷光体的阴极射线发光性质已进行了研究.在进一步研究时,我们发现在紫外线激发下,能量从Tb3+离子传递到Ce3+离子的现象.在过去的一些报导中,能量多是从Ce3+离子传递给Tb3+离子的.这种反过来传递的过程还是不多见的.

ENERGY TRANSFER PHENOMENON IN YAG:Ce,Tb

Energy transfer between different kinds of rare earth ions has been studied in various hosts coactivated by Ces and Tb3+17-14. It has been found that in all cases the excitation energy transfers from Ce3+ to Tb3+. In investigating the. photoluminescence of YAG:Ce,Tb phosphors, however, excitation energy is found to transfer from Tb3+ to Ce3+. This is shown in Fig.5 and 6 where a new excitation band appears at 270nm for YAG: Ce,Tb when the intensity of Ce3+ emission at 520nm is monitored. This band excites Tb3+ luminescence quite efficiently in YAG:Tb3+ (Fig.3) but is almost ineffective for the Ce3+ 520nm emission in YAGsCe3+ (Fig.4), unless the latter is codoped with Tb3+. These results imply that the energy absorbed by Tb3+ ions transfers to Ce3+ ions.