Structure and Photoluminescence Properties of Sm³⁺ Ion-Doped YInGe₂O₇ Phosphor

A new phosphor, Sm³⁺ ion-doped YInGe₂O₇, was synthesized using a planetary ball mill solid state reaction. The XRD patterns show that all of the peaks can be attributed to the monoclinic YInGe₂O₇ crystal structure when the Sm³⁺ ion concentration is increased up to 20 mol %. Under an excitation wavelength of 404 nm, the Sm³⁺ intra-4f transition appears in the emission spectrum including two stronger emission peaks located at 560-570 nm and 598 nm correspond to the ⁴G_5/2 → ⁶H_5/2 and ⁴G_5/2 → ⁶H_7/2 transitions, respectively, and another weak emission peak located at 645 nm is due to the ⁴G_5/2 → ⁶H_9/2 transition. The decay time decreases from 4.5 to 0.8 ms as Sm³⁺ ion concentrations increase from 1 to 20 mol %, and the decay mechanism of the ⁴G_5/2 → ⁶H_7/2 transition is a single decay component between Sm³⁺ ions only. The concentration quenching effect occurs when the Sm³⁺ ion concentration is higher than 3 mol %. The CIE color coordinate of Y_0.97Sm_0.03InGe₂O₇ phosphor is at x = 0.457 and y = 0.407, which is located in the orange-yellow light region.