NaMn_3F_(10)∶Yb/(Er,Tm,Ho)纳米颗粒的制备及光谱研究

由于具有毒性低、稳定性好、发光强度高等优点,稀土上转换纳米颗粒在细胞成像和标记方面具有十分广泛的应用前景。本文采用了常规的热分解法,制备了粒径均一、均匀分散的NaMn_3F_(10)∶Yb/(Er,Tm,Ho)上转换纳米颗粒。研究表明,制备的纳米颗粒的粒径都在10nm以下。NaMn_3F_(10)∶Yb/Er和NaMn_3F_(10)∶Yb/Tm纳米颗粒在980nm连续激光的激发下分别发射660nm和800nm的单色光,这主要归因于Mn2+离子4T1能级可以作为中间过渡能级,将Er~(3+)离子2H11/2能级和4S3/2能级上的光电子通过非辐射的方式转移到2F9/2能级上,降低2H11/2能级和4S3/2能级上的光电子数同时增加2F9/2能级上的光电子数,使2F9/2与4I15/2基态能级产生较大的粒子数反转,以产生较强的波长为660nm光辐射。通过对NaYF4∶Yb~(3+)20%,Er~(3+)2%纳米颗粒中掺杂Mn2+离子的研究发现,随着Mn2+离子掺杂浓度的提高,该纳米颗粒的发光颜色从绿色逐渐向红色转变,光谱中红绿光的强度比逐渐升高,在Mn掺杂浓度为58%时即可得到纯红光发射的上转换纳米颗粒。

Synthesis and Spectroscopic Study of NaMn3 F10∶Yb/(Er,Tm,Ho) Nanoparticles

Due to low toxicity, high stability and high photoluminescence, lanthanide doped upconversion nanoparticles has a promising appliment in bioimaging and boilable. Here, monodispersed and uniform NaMn3 F10∶Yb/( Er,Tm,Ho) nanoparticles were synthesized by common thermal decomposited method. The sizes of all synthesized nanoparticles were lower than 10 nm. It was found that the NaMn3 F10∶Yb/Er NaMn3 F10∶Yb/Tm radiated single 660 nm and 800 nm under the excitation of 980 nm continue wave laser, respectively. It mainly attribute to the act of the 4 T1 level of Mn2+ ions, which could act as the intermediate energy and facilitate the non-radiative energy transfer from the 2 H11/2 and 4 S3/2 levels to the 2 F9/2 level of Er3+ ions so that the intensity of 2 F9/2 level ( red emission) were enhanced and the intensity of 2 H11/2 and 4 S3/2 levels ( green emission) were suppressed. Finally, it was found by incorporating the Mn2+ ions into NaYF4 nanoparticles that the emission color and red/green ratio were enhanced gradually as imcreasing the Mn2+ concentration. The nanoparticles with pure red emission were obtained when the Mn2+ ions comcentration was up to 58%.