Structural characterization, continuous-wave optically stimulated luminescence, and correlation between thermoluminescence and EPR of Ce-doped Ca2Al2SiO7 phosphor synthesized by a solid-state reaction method. (November 2022)

• Record Type: Journal Article
• Authors: Cano, Nilo F.; Gonsalez-Vasquez, Amador J.; Gundu Rao, T.K.; Turpo-Huahuasoncco, Klinton V.; Canaza-Mamani, Edwar A.; Lopez-Gonzales, Alejandro H.; Javier-Ccallata, Henry S.; Ayala-Arenas, Jorge S.; Rocca, René R.; Silva-Carrera, Noemi B.; Chubaci, José F.D.; Watanabe, Shigueo
• Is Part Of: Journal of physics and chemistry of solids. Volume 170(2022)
• Publication Date: 2022-11
• Subjects: Calcium aluminosilicate (Ca2Al2SiO7) -- Thermoluminescence -- Optically stimulated luminescence -- Electron paramagnetic resonance -- Defect centers; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2022.110928
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: A calcium aluminum silicate (Ca2 Al2 SiO7 ) phosphor doped with different concentrations of cerium has been prepared by a solid-state reaction method. From X-ray diffraction (XRD) data and using the Rietveld refinement method, the phase, structure, and average crystalline size have been determined. Luminescence emissions have been investigated by optically stimulated luminescence (OSL) and thermoluminescence (TL) methods. TL studies reveal a broad peak centered at 220 °C with an emission band at 410 nm. The TL intensity of a sample doped with 0.1 mol% Ce proved to be 115 times stronger than that of an undoped sample. Electron paramagnetic resonance (EPR) has been utilized to detect the defect centers responsible for the TL process in Ce-doped Ca2 Al2 SiO7 phosphor. The observed EPR spectrum results from a superposition of three defect centers. Center I with a g -value of 2.0090 is assigned to an O − ion and exhibits hyperfine interaction with a nearby nucleus with spin 3/2. This center relates to the TL peak at 220 °C. Center II with an isotropic g -value of 2.0073 is also ascribed to an O − ion and correlates with the dominant 220 °C TL peak. Center III has a g -value of 2.0076 and is identified as an F + center (singly-ionized oxygen vacancy). Highlights: By solid-state reaction synthesis, Ca2 Si2 SiO7 :Ce 3+ powder phosphors obtained. Prepared phosphor was well characterized using XRD, TL, OSL, and EPR spectroscopy. Effect of dopant concentration, annealing temperature and γ-radiation is discussed. Ce-doped phosphor has shown a broad glow peak at 220 °C with high TL sensitivity, and with an emission band at 410 nm. The EPR signals due to the O − ion are associated with the TL peak at 220 °C.