摘要
本文利用纳秒技术和一般光谱学技术系统地研究了Ce^(3+),Tb^(3+)离子在LnBO_3(Ln=La,Gd和Y)中的发光特性和能量传递机制。发现在La_(1-x)Ce_xBO_3中Ce^(3+)离子的浓度在0.1mol以上才出现明显的浓度猝灭。故对敏化剂Ce^(3+)可以高浓度掺杂。本文对高掺杂下材料的发光特性,Ce^(3+)到Tb^(3+)能量传递的规律和机制进行了系统研究。给出了在正硼酸盐中绿色发光材料的最佳配比。
Fluorescence feature of Ce3+ and Tb3+ in LnBO3 and the energy transfer mechanism from Ce3+ to Tb3+ in borate have been systematically investigated.The quenching concentration of Ce3+ in borate can be very heavy, for example at 0.1 mol and above in LaBO3. The green emission intensity of Tb3+ is best when the concentration of Ce3+ and Tb3+ reaches 0.1 mol in LaBO3.The sensitization process of Tb3 + ions by Ce3+ ions in LnBO3 is mainly energy transfer from Ce3+ ions to Tb3+ ions (5D3 and 5D4) with nonradiative resonance process. Electrons at 5D3 level transit into 5D4 level of Tb3+ ion by cross relaxation. Thus the green emission (5D4-7F7, 544nm) intensity of Tb3+ reaches the maximum when the concentration of Tb3+ is at 0.1mol. In the case of heavy doping the blue emission (5D3-7F7) can not be seen.With surveying the fluorescence decay of Ce3+ in borate doped with different concentration of Tb3+ , it is found that the experimental results accord well with theoretical values. The mechanism of nonradiative resonance energy transfer is found to be dipole-dipole interaction. The critical transfer distance R0 is approximately 7.7A and 6.5 A in LaBO3 and GdBO3 respectively. The probability and efficiency of the energy transfer have also been calculated. The efficiency of the energy transfer from Ce3+ to Tb3+ might leach 90% and above in LaBO3 when the concentration of Ce3+ and Tb3+ is at 0.1 mol.Further research has indicated that energy diffuse within the sensitizer (Ce3+) affects the energy transfer process from Ce3+ ions to Tb3+ ions.
出处
《发光学报》
EI
CAS
CSCD
北大核心
1990年第2期96-103,共8页
Chinese Journal of Luminescence
基金
国家自然科学基金
