A series of monodisperse size-controllable amorphous Gd(OH)CO₃ spherical particles with good dispersity have been prepared by a simple homogeneous precipitation route with ethylene glycol (EG) as auxiliary solvent. The average diameters of precursor spheres can be tuned in the range of 70–220 nm by simply changing the volume ratios of EG/H₂O in the solvent. In general, the particle size of the spherical particles gradually increases by enhancing the proportion of H₂O for the mixing solvent of EG/H₂O. Moreover, the long flakes and sheet-like microstructures of the crystalline precursors [Gd₂O(CO₃)₂∙H₂O] are obtained by increasing reaction temperature or prolonging reaction time. Thus, the multiform precursors with tunable morphologies and particle sizes have been achieved by systematically adjusting the reaction conditions. It is worth pointing out that the corresponding gadolinium oxide (Gd₂O₃) products perfectly inherit the good morphology, unifomity, and dispersity of the precursor particles except for a shrinkage in diameters after an annealing process in air, resulting in the uniform and well-dispersed Gd₂O₃ spheres with tunable particle sizes (50–180 nm). The lanthanide ions (Ln³⁺) doped samples exhibit their corresponding characteristic down-conversion (DC) or up-conversion (UC) multicolor emissions under UV or NIR excitation. The size-dependent luminescence properties of the Ln³⁺-doped phosphors are also investigated in detail. The as-manufactured LED device prepared by the phosphor and LED chip can exhibit characteristic emission of activator ion, which directly prove the potential applications of the phosphors in LEDs and optoelectronics. Furthermore, the as-proposed synthesis strategy may provide some insight for the design and fabrication of other rare earth functional materials with controllable morphology and particle sizes.

以乙二醇(EG)为辅助溶剂，通过简单的均相沉淀路线制备了一系列具有良好分散性的单分散粒径可控无定形Gd(OH)CO ₃球形颗粒。通过简单地改变溶剂中 EG/H ₂ O的体积比，前体球体的平均直径可以在 70-220 nm 的范围内调整。一般来说，随着EG/H ₂ O混合溶剂中H ₂ O比例的增加，球形颗粒的粒径逐渐增大。此外，结晶前驱体[Gd ₂ O( CO ₃ ) ₂ ∙ H ₂O]是通过提高反应温度或延长反应时间获得的。因此，通过系统地调整反应条件，已经实现了具有可调形态和粒径的多形式前驱体。值得指出的是，相应的氧化钆 (Gd ₂ O ₃ ) 产品完美地继承了前驱体颗粒良好的形貌、均匀性和分散性，但在空气中退火处理后直径有所缩小，从而形成均匀良好的颗粒。 - 分散的 Gd ₂ O ₃球体，粒径可调（50-180 nm）。镧系离子（Ln ³⁺) 掺杂样品在 UV 或 NIR 激发下表现出相应的特征下转换 (DC) 或上转换 (UC) 多色发射。还详细研究了掺杂Ln ^{3+ 的}磷光体的尺寸依赖性发光特性。由荧光粉和LED芯片制备的LED器件可以表现出活化剂离子的特征发射，这直接证明了荧光粉在LED和光电子领域的潜在应用。此外，所提出的合成策略可以为其他具有可控形态和粒径的稀土功能材料的设计和制造提供一些见解。