Abstract Terbium doped calcium fluoride (CaF2:Tb3+) and cerium co-doped CaF2:Tb3+ (CaF2:Ce3+, Tb3+) nanoparticles were synthesized by the hydrothermal method by using citric acid (Cit) as surfactant. The as-synthesized nanoparticles have good dispersibility in water to form an aqueous transparent dispersion at a concentration of 20 mg/mL. The nanoparticles have the CaF2-type cubic structures. Photoluminescence (PL) investigation showed that energy transfer can be occurred effectively from Ce3+ ions to Tb3+ ions in Cit/CaF2: Ce3+, Tb3+ nanoparticles. And the PL intensity of Cit/CaF2: Ce3+, Tb3+ nanoparticles is very strong at a low concentration of 1 mg/mL, which is 16-fold as high as that of Cit/CaF2: Tb3+ nanoparticles. The strong green emission from Cit/CaF2: Ce3+, Tb3+ nanoparticles can selectively be quenched by Cu2+ ions in comparison to other metal ions and its detection limit is 1.02 × 10−5 M in an aqueous solution. The PL quenching is reversible by the addition of ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) with the recovery of almost 80% of the original PL. The results revealed that Cit/CaF2: Ce3+, Tb3+ nanoparticles could find a promising application for the detection of Cu2+ ions in an aqueous solution.

中文翻译：

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高发光 Cit/CaF2：Ce3+、Tb3+ 纳米颗粒和 Cu2+ 离子检测

摘要 以柠檬酸(Cit)为表面活性剂，采用水热法合成了铽掺杂氟化钙(CaF2:Tb3+)和铈共掺杂CaF2:Tb3+(CaF2:Ce3+,Tb3+)纳米颗粒。合成的纳米颗粒在水中具有良好的分散性，以 20 mg/mL 的浓度形成透明的水分散体。纳米颗粒具有CaF2 型立方结构。光致发光 (PL) 研究表明，在 Cit/CaF2: Ce3+、Tb3+ 纳米粒子中，能量可以有效地从 Ce3+ 离子转移到 Tb3+ 离子。并且Cit/CaF2:Ce3+、Tb3+纳米粒子的PL强度在1mg/mL的低浓度下非常强，是Cit/CaF2:Tb3+纳米粒子的16倍。Cit/CaF2: Ce3+ 的强烈绿色发射，与其他金属离子相比，Tb3+ 纳米粒子可以被 Cu2+ 离子选择性淬灭，其检测限为 1.02 × 10-5 M 在水溶液中。通过添加乙二胺四乙酸二钠盐 (EDTA-2Na)，PL 猝灭是可逆的，几乎可以恢复 80% 的原始 PL。结果表明，Cit/CaF2:Ce3+、Tb3+ 纳米颗粒可用于检测水溶液中的 Cu2+ 离子。