New long-afterglow phosphors: Yb2+-doped strontium aluminates

- New long-afterglow phosphors (Yb2+-doped strontium aluminates) were made.
- The phosphor Sr4Al14O25:Yb2+, Dy3+ shows a long afterglow property.
- Intensity of the afterglow is much weaker than the phosphor Sr4Al14O25:Eu2+, Dy3+.