Color-tunable emission and non-contact optical temperature sensing performance in NaY9Si6O26: Ce3+, Eu3+ phosphors

In this article, the tunable-color emission properties of Ce³⁺/Eu³⁺ in NaY₉Si₆O₂₆ phosphors were reported. Ce³⁺ and Eu³⁺ ions had effectively incorporated the sites of Na⁺ and Y³⁺ ions, which were revealed by Rietveld refinements. The site occupation preference of Ce³⁺ in cationic sites were discussed. The energy transfer from Ce³⁺ to Eu³⁺ ion under the 312 nm excitation was ascribed to dipole-dipole interaction mechanism based on Dexter's energy transfer theory of multipolar interaction, which makes NaY₉Si₆O₂₆: Ce³⁺, Eu³⁺ produce tunable-color emission. Additionally, the temperature dependent emission spectra of the powders were studied. Temperature sensing performances were reflected by the fluorescence intensity ratio based on different temperature dependent variation tendency of Ce³⁺ and Eu³⁺ ions. The maximum values of the absolute and relative sensor sensitivities of NaY₉Si₆O₂₆: Ce³⁺, Eu³⁺ phosphors were about 0.0328 K⁻¹ and 0.95 % K⁻¹, respectively. Above all, NaY₉Si₆O₂₆: Ce³⁺, Eu³⁺ phosphors show a promising prospect for optical thermometer applications.