BaGd2(MoO4)4:Tb3+,Eu3+荧光粉的 发光特性与能量传递机理

利用高温固相法制备了BaGd_2(MoO_4)_4∶Tb~(3+)与BaGd_2(MoO_4)_4∶Tb~(3+),Eu~(3+)荧光粉,并借助于X射线衍射(XRD)、激发光谱、发射光谱及荧光衰减曲线对样品的结构及发光性能进行了表征。在290 nm激发下,BaGd_2(MoO_4)_4∶Tb~(3+)样品在550 nm处具有较强的绿光发射,表明该样品可用作绿色荧光粉。Tb~(3+)离子的最佳掺杂浓度为50%,电偶极间相互作用是引起浓度猝灭效应的主要原因。当在BaGd_2(MoO_4)_4∶Tb~(3+)荧光粉中共掺入Eu~(3+)离子后,可同时观测到Tb~(3+)与Eu~(3+)离子的特征发射峰。随Eu~(3+)掺杂浓度的升高,Tb~(3+)离子的发光强度逐渐下降,而Eu~(3+)离子的发光强度逐渐增加。根据BaGd_2(MoO_4)_4∶Tb~(3+),Eu~(3+)中Tb~(3+)离子的荧光寿命计算了Tb~(3+)与Eu~(3+)离子间的能量传递效率,并根据荧光寿命与激活离子掺杂浓度的关系证实了能量传递机制为电偶极间相互作用。

Luminescent Characters and Energy Transfer Mechanisms of BaGd2(MoO4)4:Tb3+,Eu3+ Phosphors

BaGd₂(MoO₄)₄:Tb³⁺ and BaGd₂(MoO₄)₄:Tb³⁺,Eu³⁺ phosphors were synthesized by high temperature solid state method and their structure and luminescent properties were analyzed by means of X-ray diffraction, excitation and emission spectra, and luminescent decay curves. Under excitation of 290 nm, BaGd₂(MoO₄)₄:Tb³⁺ phosphors give rise to a intense green emission at 550 nm, indicating the samples can be used as green-emitting phosphors. The optimum concentration of Tb³⁺ ions is 50%, and the dipole-dipole interaction is the main reason for the concentration quenching. As the Eu³⁺ ions were co-doped in BaGd₂(MoO₄)₄:Tb³⁺ phosphors, the characteristic emissions of both Tb³⁺ and Eu³⁺ ions can be observed. With the increasing concentration of Eu³⁺ ions, the emission intensities of Tb³⁺ ions decreased, while those for Eu³⁺ ions were enhanced. The energy transfer efficiencies between Tb³⁺ and Eu³⁺ ions were calculated on the basis of lifetimes of Tb³⁺ ions in BaGd₂(MoO₄)₄:Tb³⁺,Eu³⁺, and the energy transfer mechanism was confirmed to be dipole-dipole interaction according to the relations between lifetimes and activator concentrations.