通过水热法制备了碱金属离子(Li+、Na+、K+)共掺的MgSc2O4∶Er3+/Yb3+ 纳米晶,获得类球状纳米晶的平均尺寸约为35 nm。通过改变碱金属离子的种类和数量,获得了增强上转换发光。发现K+离子共掺MgSc2O4∶Er3+/Yb3+纳米晶发光强度最佳,并且随着K+掺杂量的不断增加,纳米晶的发射强度逐渐增强,这是由于K+离子引入了最大的晶体场不对称性。随后,通过调控Yb3+和Er3+的掺杂浓度,发现发光强度最强样品为K+离子共掺MgSc2O4∶1%Er3+/5%Yb3+纳米晶。研究了在980 nm激光激发下,MgSc2O4纳米晶中Yb3+与Er3+离子之间的能量传递以及上转换发光机制。

The alkali ions(Li+/Na+/K+) co-doped MgSc2O4∶Er3+/Yb3+ nanocrystals have been synthesized by hydrothermal method. The average size of obtained spheroid nanocrystals is about 35 nm. The upconversion luminescence intensity can be strengthened by adjusting alkali ions types and contents. The K+ ions co-doped MgSc2O4∶Er3+/Yb3+ nanocrystals display the strongest luminescence. As K+ content increasing, emission intensity can be enhanced gradually due to the large asymmetry of crystal field created by K+ ions. The spectral properties of K+ ions co-doped MgSc2O4∶Er3+/Yb3+ nanocrystals are described in detail as a function of Er3+ and Yb3+ concentrations. The MgSc2O4∶1%Er3+/5%Yb3+ nanocrystal was optimized for the strongest upconversion luminescence. Then, the upconversion mechanism and energy transfer processes between Yb3+ ions and Er3+ ions in K+ ions co-doped MgSc2O4∶Er3+/Yb3+ nanocrystals were investigated under the 980 nm excitation．