Luminescence of some lanthanides in synthetic yttrium gagarinite (NaCaYF6)

NaCaYF₆ is the formula for gagarinite. Noting the lack of luminescence studies in this material, we synthesized it using the hydrothermal method and investigated the luminescence of several lanthanides. Characteristic luminescence of Eu${}^{3+}$, Dy${}^{3+}$, Sm${}^{3+}$ and Tb${}^{3+}$ was observed. Detailed results on photoluminescence emission and excitation spectra, lifetime, chromaticity coordinates and concentration dependence of emission intensity are presented. Except for Tb${}^{3+}$, which exhibits f-d excitation, the luminescence of other activators got quenched at 1$$mol % concentration. Eu${}^{3+}$ emission in this host was peculiar, in that the emissions from higher ⁵D states were observed. Luminescence characteristics are explained using the known energy level diagrams for the lanthanide activators.