Authors: X. Sun, X.Y. Hu, J. Fan, S.C. Zhan, Y. Wang, Z.Z. Wang, Q. Sun, Y.Y. Hao
Affilation: Northwest University, China
Pages: 164 - 167
Keywords: CaF2, hollow spheres, down-conversion, luminescence
Highly uniform and well-dispersed CaF2 microsphere and hollow spheres with tunable particles size (100nm-900nm) have been successfully synthesized by a facile hydrothermal process using ethylenediaminetetraacetic acid disodium as a complexing reagent. The XRD results indicated that the as-prepared microspheres were of cubic phases and had good crystallinity and purity. The TEM and SEM results reveal that the size of the CaF2 can be controlled from 100 nm to 900 nm by adjusting the pH value. Excitation and emission spectra are shown that the samples can absorb the ultraviolet light around a broad band from 200 nm to 350 nm with maximum peaks at 213 nm and 300 nm and a weaker band at 255nm, then emits light at 335 nm which corresponds to the transitions from 5D to 4F of Ce3+, 480 nm, 540 nm, 583 nm, 620 nm which corresponds to the transitions from 5D4 to 7F6、5、4、3 of Tb3+. It is clear that emission intensity of Ce3+ decreases with increasing Tb3+, it shows that efficient energy transfer from Ce3+ to Tb3+ may occur.