Y_3Al_5O_(12)基质中Dy^(3+)的浓度猝灭机制

Mechanism of concentration self-quenching of Dy^(3+) ions in Y_3Al_5O_(12)

采用溶胶-凝胶/燃烧合成法制备不同掺杂浓度的Dy:Y3Al5O12(YAG)发光粉体。分析基质晶体结构、Dy3+掺量对Dy3+光致发光性能的影响,并探讨Dy3+在Y3Al5O12基质中的自身浓度猝灭机制。根据激发光谱,Dy:YAG的主激发峰位置在353 nm,对应Dy3+的6H15/2→6P7/2跃迁。在Dy:YAG晶体结构中,Dy3+取代Y3+的位置具有D2对称性,故Dy:YAG的蓝光发射强度要高于黄光发射强度,且Dy3+最佳摩尔分数为0.02;Dy3+的4F9/2→6H15/2、6H13/2跃迁发射的浓度猝灭机制均为相邻中心的电偶极-电偶极相互作用引起的交叉弛豫(4F9/2+6H15/2→6H9/2+6F3/2)所造成的。

Dy：YAG phosphors with different doping concentrations were synthesized by the sol-gel combustion method.The dependence of the host crystal structure,and the Dy3＋ concentration on the luminescent properties,and the mechanism of concentration self-quenching of Dy3＋ were analyzed.Results indicated that the strongest excitation peak located at 353 nm corresponding to the 6H15/2→6P7/2 transition of Dy3＋.In crystalline YAG,the Dy3＋ ions occupied Y3＋ sites whose point symmetry was D2 with an inversion center,so the maximum emission peak was 481 nm（blue luminescence）.According to the dependence of the concentration of Dy3＋ in Y3Al5O12 under the excitation of 353 nm,the optimum concentration for Dy3＋ in Y3Al5O12 was x（Dy）=0.02.It was confirmed that the mechanism of concentration self-quenching of Dy3＋ 4F9/2→6H15/2,6H13/2 transition was the cross relaxation（4F9/2＋6H15/2→6H9/2＋ 6F3/2） caused by the electric dipole-dipole interaction between Dy3＋ ions.