Radiation-induced reduction of Eu3+ doped in SrAl2O4

Abstract In this letter, we report radio-photoluminescence (RPL) properties of Eu-doped SrAl2O4. The RPL is a phenomenon in which a new luminescence center is generated by ionizing radiation. The material was synthesized via the solid-state reaction. The synthesized sample shows photoluminescence (PL) due to the 4f-4f transition of Eu3+ and the 4f65d1 → 4f7 transition of Eu2+. After X-ray irradiation, the former emission intensity decreases while the latter one increases, and the extent of the change depends on the radiation dose. The change in the RPL is attributed to a reduction of Eu3+ by trapping an X-ray generated electron (Eu3+→Eu2+). In addition, a heat-treatment effectively reverses the above reaction by detrapping an electron from the Eu2+ center.