Effects of Sc3+ ions on local crystal structure and up-conversion luminescence of layered perovskite NaYTiO4: Yb3+/Er3+

This work focused on influences of Sc 3+ dopants on local site symmetry and ligand field of Er 3+ activators as well as its up-conversion luminescence performances sensitized by Yb 3+ ions in NYTiO 4 (NYT). The structure analysis and Judd-Ofelt calculation confirmed that doping Sc 3+ ions could lower site symmetry as well changed the ligand field around Er 3+ ions. The introduction of Sc 3+ ions induced variations of crystal lattices , regulated distances between Er 3+ ions and Er 3+ or Yb 3+ ions, and thus influenced the up-conversion luminescence properties . Besides, time-resolved decay curves figured out the great enhancement of lifetime and luminescence quantum efficiency for both green and red emissions due to Sc 3+ dopants. For optical temperature sensitivity, thermally coupled levels (TCLs) for blue emission 4 F 5/2 / 4 F 7/2 → 4 I 15/2 was studied for the first time. Besides, TCLs for violet emission 4 G 11/2 / 2 H 9/2 → 4 I 15/2 as well as green emission 2 H 11/2 / 4 S 3/2 → 4 I 15/2 were also recorded. By tri-doping Sc 3+ ions into NYT: Yb/Er, both absolute sensitivity and relative sensitivity of above three TCLs were improved with temperature uncertainty decreasing.