Facile modulation the sensitivity of Eu2+/Eu3+-coactivated Li2CaSiO4 phosphors through adjusting spatial mode and doping concentration

Abstract

Abstract Series of Eu 2+ /Eu 3+ -coactivated Li 2 CaSiO 4 phosphors were prepared by solid-state reaction technique. All the samples emitted the unique emissions of Eu 2+ and Eu 3+ ions when excited by 395 nm, while the strongest emission intensity was received when x = 0.03. On the basis of theoretical discussion, it is evident that crossover relaxation should be responsible for the thermal quenching mechanism which was further proved by the unchanged lifetime at elevated temperature. Besides, through analyzing the inconsistent responses of the emission intensities of the Eu 2+ and Eu 3+ ions to the temperature, the optical thermometric properties of the designed phosphors were studied. By selecting different emissions of Eu 3+ ions and combining with that of the Eu 2+ ions, adjustable sensitivities were realized in the resultant phosphors. Furthermore, the sensitivities of the studied compound were also found to be greatly affected by the doping concentration. The maximum absolute and relative sensitivities of the synthesized compounds were 0.0025 K −1 and 0.289% K −1 , respectively. These achieved results implied that the Eu 2+ /Eu 3+ -coactivated Li 2 CaSiO 4 phosphors were promising candidates for optical thermometry. Additionally, this work also provided promising methods to modulate the sensitivities of the luminescent compounds by adjusting spatial mode and doping concentration.

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