Multi-color Ca3Ga4O9: Pr3+phosphors for high-security-level optical information storage

Optical information storage phosphors with multicolor have attracted a lot of attention because it can increase the storage capacity and security. Herein, a series of Ca3-xGa4O9: xPr3+ phosphors with multicolor emission and multiple depth have been synthesized by high-temperature solid-state methods. The structure analysis shows the emitting center Pr3+ tends to occupy the lattice sites of Ca2+ due to their comparable ionic radius. When excited at a wavelength of 258 nm, the phosphors of Ca3-xGa4O9: xPr3+ exhibit bright white emission. The trap depths of the phosphors are calculated by thermoluminescence curves, and two distinct trap distribute at 0.67 and 0.97 eV, characterized by minimal interference. Typically, the Ca3-xGa4O9: xPr3+ phosphors are capable of recording optical information when exposed to 254 nm UV light or X-rays, and this stored information can later be retrieved through thermal stimulation. In addition to changes in luminescence intensity, the thermoluminescence color of Ca3-xGa4O9: xPr3+ also changes from white to red as the temperature increase from 298 K to 573 K, suggesting the prospective application in optical information security.