采用溶剂热法成功制备了Nd3+敏化的掺杂Ca2+的NaYF4∶Yb/Tm/Ca@NaGdF4∶Nd/Yb核-壳上转换纳米粒子。 针对Tm3+多光子过程中产生的蓝色及紫外上转换发光,研究了敏化剂Nd3+、Yb3+的含量以及激发功率等关键因素对荧光性能的影响,并用介孔二氧化硅(mSiO2)对其表面进行修饰,得到具有良好亲水性的上转换纳米粒子,通过TEM、XRD、FT-IR和荧光光谱对其形貌、结构和荧光性能进行表征。结果表明,制备的纳米粒子为纯六角相,表面均匀地包覆了一层mSiO2,在808 nm近红外光激发下,壳层中Nd3+和Yb3+的摩尔分数分别为50%和10%时表现出强烈的上转换蓝光(1D2→3F4,1G4→3H6)和紫外光(1I6→3F4,1D2→3H6),在光动力疗法和荧光成像方面具有潜在的应用价值。

The Nd3+-sensitized Ca2+-doped NaYF4∶Yb/Tm/Ca@NaGdF4∶Nd/Yb core/shell upconversion nanoparticles were successfully prepared by solvothermal method. The effects of key factors such as the content of sensitizers Nd3+ and Yb3+ and the excitation power on the fluorescence performance were studied for the blue light and UV up-conversion emission generated in the Tm3+ multi-photon process. To obtain up-converting nanoparticles with good hydrophilicity, the UCNPs surface was modified with mesoporous silica(mSiO2). Its morphology, structure and fluorescence properties were characterized by TEM, XRD, FT-IR and fluorescence spectroscopy. The results showed that the prepared nanoparticles were pure hexagonal phase, the surface was evenly modified with a layer of mSiO2. Then, under the excitation of 808 nm near infrared light, when the mole fraction of Nd3+ and Yb3+ in the shell was 50% and 10% respectively, it shows strong up-conversion blue light(1D2→3F4, 1G4→3H6) and ultraviolet light(1I6→3F4, 1D2→3H6). The research will have potential application prospects in photodynamic therapy and fluorescence imaging.