稀土发光材料(La_(1-x)Gd_x)OBr:Tb,Ce中的能量传递

Energy Transfer in (La1-x Gdx) OBr: Tb, Ce

在紫外光激发下,(La_(1-x)Gd_x)OBr:Tb_(0.0075),Ce_y中Gd^(5+)、Ce^(3+)、Tb^(3+)可各自吸收激发能。Ce^(3+)和Tb^(3+)发光,Ge^(3+)不发光,但可将能量传递给Ce^(3+)和Tb^(3+)发光。Ce^(3+)和Tb^(3+)之间可能有可逆的能量传递。Gd的存在改变晶场分布,使Ce^(3+)激发带长波端红移,有利于Tb^(3+)+5D_3→Ce^(3+)→Tb^(3+5)D_4的能量传递,敏化人眼敏感的绿光发射,也有利于Tb^(3+)和Ce^(3+)发光的温度稳定性。

Gd3+, Ce3 + and Tb3+ in (La1-x Gdx OBr: Tb0.0075, Cey can be excited with different wavelengths in ultra-violet region. Ce3+ and Tb3+ radiate. No Gd3+ characteristic luminescence has been observed, yet the energy of excited Gd3+transfers to Ce3 + and Tb3+, thus contributes to their radiations conssque-rtly. Energy transfer may be reversible to some extent between Ce3 + and Tb3+. The existance of Gd changes the crystal field distribution makes some red shift of the Ce3+ excited band and causes more Tb3 + 5D3→Ce3+→Tb3 + 5D4 energy transfer. These energy transfer processes result in the strengthen of greenish luminescence to which the naked eye is most sensitive, also result in the improvements of temperature stability of both Ce3+ and Tb3+ luminescence.