Controllable synthesis of tetragonal LiScF4:Yb3+, Er3+ nanocrystals and its upconversion photoluminescence properties

Tetragonal rare-earth ions codoped LiScF4 nanocrystals have been synthesized by a modified solvothermal method. The results revealed that the phase and morphology can be tailored through varying the synthesis conditions, such as reaction temperature and time. Meanwhile, the UC fluorescence emission spectra were measured. It turned out that the UC emission intensity can be significantly influenced by reaction temperature and time. Different from the NaYF4:20%Yb3+,2%Er3+ nanocrystals that usually emit green emission, yellow color emission can be observed in the LiScF4:20%Yb3+,2%Er3+ samples under 980 nm excitation, which illustrates that the obtained new phase LiScF4 is suitable as a promising host for efficient UC fluorescence generation and tunable UC emission spectra. Moreover, the UC mechanism was investigated in detail.