中文摘要：

稀土上转换发光纳米材料具有极好的生物应用前景，但其应用的前提是能制备出水溶性、发光效率高的稀土纳米材料。以乙二醇为溶剂、稀土氯化物和NaF为反应物，采用简易的溶剂热法一步制备出水溶性的NaYF4：Yb，Er纳米颗粒。NaYR：Yb，Er样品以粒径为25-40nm的球形颗粒为主，同时含有少量直径为25～40nm、长度为50～100nm的虫状纳米颗粒。该样品具有立方相结构，样品表面上的乙二醇配体使其能够很好地分散于水中。在980nm激光器激发下，NaYF4：Yb，Er纳米颗粒水溶液展现了强的黄绿色上转换发光。因此该样品拥有良好的生物应用潜力。

英文摘要：

Rare-earth upconverting nanophosphors have great superiority as luminescent labeling materials for biological applications. A prerequisite for their biological applications is to gain access to prepare water-soluble nanoparticles with appropriate functional groups and high luminescent efficiencies. The water-soluble NaYF4 ： Yb,Er nanoparticles are prepared by a simple solvothermal method, using ethylene glycol as a solvent, rare earth chloride and NaF as reactants. The resulting NaYF4 ： Yb, Er nanoparticles are mainly spherical particles with diameter of 25-40nm, and including a small quantity of nano-worms with diameter of 25-40nm and length of 50-100nm. They exhibit cubic-phase structure, and the presence of ethylene glycol ligands on their surface confers high solubility in water. Under continuous-wave excitation of 980nm laser, aqueous solution of NaYF4 ： Yb,Er nanoparticles exhibits strongly yellow- green upconverting luminescence. Therefore, the present NaYF4 ： Yb,Er nanoparticles are potential candidates in biological applications.