Broad color tuning and Eu3+-related photoemission enhancement via controllable energy transfer in the La2MgGeO6:Eu3+,Bi3+ phosphor
Broad color tuning and Eu3+-related photoemission enhancement via controllable energy transfer in the La2MgGeO6:Eu3+,Bi3+ phosphor
复制标题
DOI：
10.1039/c8qi00126j
复制
发表时间：
2018-05
影响因子：
7
通讯作者：
W. Xie;Mo Youwei;C. Zou;Fengwen Kang;Guohuan Sun
中科院分区：
文献类型：
--
作者：
W. Xie;Mo Youwei;C. Zou;Fengwen Kang;Guohuan Sun
近年来，如何采用一种可行的策略来设计具有调色性能和增强光电发射性能的新型荧光粉已成为一个热门的研究课题。在这里，我们报道了一系列紫外光转换的Eu3+，Bi3+掺杂的La2MgGeO6荧光粉，它可以同时实现广泛的颜色调谐和Eu3+相关的荧光增强。结构分析表明，所有样品均为三方晶系，空间群为R3(146)，Eu3+和Bi3+离子倾向于取代La3+离子，而不是Mg2+和Ge4+离子。光致发光(PL)结果表明，在紫外区(如248 nm、292 nm和393 nm)的激发使Bi3+掺杂的La2MgGeO6荧光粉呈现出单一的蓝色发射带(即412 nm)，对应于Bi3+离子和Eu3+离子的特征3P1→1S0跃迁，并显示出与Eu3+离子的5D0→7FJ(J=1，2，3和4)跃迁相对应的尖锐的发射线。此外，我们还研究了Bi3+到Eu3+离子之间的能量传递机制，基于荧光光谱的结果和理论计算，我们揭示了这种能量传递过程是通过偶极-四极(d-q)相互作用发生的，并且可以增强Eu3+相关的荧光强度，从而导致298 nm激发时颜色从蓝色调谐到红色。为了更清楚地说明我们的实验观测结果，我们还建立了一个基于Bi3+和Eu3+离子的能量转移和简化的光谱能级的机制轮廓。这项研究不仅为紫外光转换可调谐荧光粉家族增加了新的成员，而且为发现更多的单相荧光粉提供了新的见解，这些单相荧光粉利用能量转移相互作用同时增强了发光和发射颜色。
Recently, how to employ a feasible strategy to design novel phosphors with color-tuning properties and enhanced photoemission has become a hot research subject. Herein, we report a series of UV-converted Eu3+, Bi3+-doped La2MgGeO6 phosphors, which enable broad color tuning and Eu3+-related fluorescence enhancement simultaneously. Structural analysis shows that all samples crystallize in a trigonal structure with the space group R3 (no. 146), and Eu3+ and Bi3+ ions tend to substitute La3+ ions rather than Mg2+ and Ge4+ ions. Photoluminescence (PL) results show that excitation in the UV spectral region (e.g., 248 nm, 292 nm, and 393 nm) enables the Bi3+-doped La2MgGeO6 phosphors to exhibit a single blue emission band (i.e., 412 nm) that corresponds to the characteristic 3P1 → 1S0 transition of Bi3+ ions and Eu3+-doped La2MgGeO6 phosphors to show sharp emission lines that correspond to the characteristic 5D0 → 7FJ (J = 1, 2, 3, and 4) transitions of Eu3+ ions. In addition, we studied the energy transfer mechanism from Bi3+ to Eu3+ ions, and on the basis of the PL results and theoretical evaluations, we revealed that this energy transfer process occurred via a dipole–quadrupole (d–q) interaction and could enhance Eu3+-related fluorescence intensity and thus led to color tuning from blue to red upon excitation at 298 nm. To illustrate our experimental PL observations more clearly, a mechanistic profile based on the energy transfer and simplified spectral energy levels of Bi3+ and Eu3+ ions is also established. This study not only adds a new member into the family of UV-converted tunable phosphors, but also provides new insights into the discovery of more single-phase phosphors with simultaneous PL enhancement and emission color tuning for UV-converted wLEDs using the energy transfer interaction.