ESR and TL/OSL/PL studies of radiation-induced defects in SrAl₂O₄:Ce³ ⁺ phosphor with high luminescent sensitivity

Cano N.F.; López-Flores B.J.; Canaza E.A.; Mosqueira-Yauri J.; Ayala-Arenas J.S.; Rocca R.R.; Chubaci J.F.D.; Rao T.K.G.; Benavente J.F. · Journal of Alloys and Compounds (2026) · DOI: 10.1016/j.jallcom.2026.190590

Resumen

The SrAl₂O₄:Ce³⁺ phosphor was synthesized via a solid-state reaction. Photoluminescence (PL) studies revealed an emission peak centered at 425 nm with excitation at 352 nm. The thermoluminescence (TL) glow curve exhibited peaks at 90, 142, and 223 °C, with light emission centered at 425 nm. The phosphor exhibited a linear dose response in the ranges of 70 − 800 mGy for TL and 90 − 1500 mGy for optically stimulated luminescence (OSL). The kinetic parameters of the TL peaks were evaluated by deconvolution, and the OSL decay curve was decomposed into three exponential components corresponding to different trap depths. A correlation was found between the PL, TL, and OSL responses. Electron spin resonance (ESR) studies enabled the identification of four defect centers induced by ionizing radiation. Center I, with a four-line hyperfine splitting, is tentatively attributed to an O⁻ ion and is linked to the TL peak at 223 °C. Center II, with an eight-line spectrum and a g-value of 2.0105, is also tentatively attributed to an O- ion and is associated with the TL peak at 142 °C. Centers III and IV are tentatively attributed to F⁺ centers, corresponding to oxygen vacancies. The correlation between ESR and luminescence constitutes the main contribution of this work, as it allowed us to establish a charge transfer mechanism in SrAl₂O₄:Ce³⁺.

Instituciones: Universidad Nacional de San Agustín de Arequipa