Rare earth (RE) pentaborates, both α- and β-polymorphs, are good candidates for photoluminescent hosts suitable for various RE activators. Ce³⁺ acts not only as an activator itself, but also as a sensitizer to other rare earth activators, like in the case of commercial green phosphor CeMgAl₁₁O₁₉:Tb³⁺. In this work, two solid solutions of β-La_0.9–xCe_0.1Tb_xB₅O₉ (0 ≤ x ≤ 0.15) and β-La_0.9–yCe_0.1Dy_yB₅O₉ (0 ≤ y ≤ 0.07) were prepared by sol–gel method with high crystallinity, and the phase purity was confirmed with careful analyses on powder X-ray diffraction patterns. Energy transfers are expected due to the overlapping of Ce³⁺ emission with the Tb³⁺/Dy³⁺ excitation. Indeed, the steady photoluminescence spectra indicate the decrease of the Ce³⁺ emission and the increase of the Tb³⁺/Dy³⁺ emission, and the fluorescence decay curves exhibit the decrease of the average lifetime of Ce³⁺. The energy transfer efficiency is estimated to be 60% at x = 0.15 and 55% at y = 0.07, respectively. The mechanism is likely through the dipole–dipole electric interactions for both cases. With this rationale, the Tb³⁺ and Dy³⁺ emissions are greatly enhanced, in particular, the white emission of Dy³⁺ in β-La_0.85Ce_0.1Dy_0.05B₅O₉ is enhanced by 20 times.

稀土 (RE) 五硼酸盐，包括 α- 和 β- 多晶型物，是适用于各种 RE 活化剂的光致发光主体的良好候选者。Ce ³⁺本身不仅作为活化剂，而且作为对其他稀土活化剂的敏化剂，例如在商业绿色荧光粉CeMgAl ₁₁ O ₁₉ :Tb ³⁺的情况下。在这项工作中，β-La _{0.9– x} Ce _0.1 Tb _x B ₅ O ₉ (0 ≤  x  ≤ 0.15) 和 β-La _{0.9– y} Ce _0.1 Dy _y B ₅ O ₉ (0 ≤  y ≤ 0.07）通过溶胶-凝胶法制备具有高结晶度，并通过仔细分析粉末 X 射线衍射图确定相纯度。^{由于 Ce 3+}发射与 Tb ³⁺ /Dy ³⁺激发的重叠，预计能量转移。事实上，稳定的光致发光光谱表明Ce ³⁺发射减少，Tb ³⁺ /Dy ^{3+发射增加，荧光衰减曲线显示Ce 3+}平均寿命下降。能量转移效率在x  = 0.15时估计为 60%，在y时估计为 55% = 0.07，分别。对于这两种情况，该机制可能是通过偶极 - 偶极电相互作用。基于此原理，Tb ³⁺和Dy ³⁺发射大大增强，特别是β-La _0.85 Ce _0.1 Dy _0.05 B ₅ O _9中Dy ³⁺的白发射增强了20倍。