Impact of organic additives on synthesis and upconversion luminescence properties in Ln3+, Yb3+ (Ln3+=Er3+/Tm3+/Ho3+) doped CaSc2O4 nanocrystals via hydrothermal method

The influence of organic additives (Cit-3Na、EDTA、CTAB et al.) on structure, crystallinity, morphology and upconversion properties for CaSc2O4 nanocrystals was investigated by hydrothermal synthesis. Via adding organic additives, we obtain rod-like and square-like CaSc2O4 nanocrystals. The sample choosing Cit-3Na as organic additive exhibits the best uniformity, monodispersity, narrowest size distribution and strongest red emission, which is enhanced by a factor of 2.5, in comparison with no adding the organic additives. Simultaneously, the upconversion luminescence properties and mechanism of Ln3+/Yb3+ (Ln3+ = Er3+/Tm3+/Ho3+) doped CaSc2O4 nanocrystals were investigated by the spectra distribution and power dependence. The emitting color of CaSc2O4 nanocrystals can be tuned from blue to green and red. The results reveal that CaSc2O4: Er3+/Yb3+ nanocrystals is a perfect red emission material and CaSc2O4 is an ideal host for upconversion luminescence.