Luminescent Properties of Yttrium–Scandium Phosphate Solid Solutions Doped with Europium Ions

The luminescent properties of Y 1 – x Sc x PO 4 : 0.5 mol % Eu 3+ ( x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) solid solutions are studied at the excitation by the radiations of ultraviolet and vacuum-ultraviolet ranges. The disordering of the solid-solution crystal structure is shown to influence the structure of the Eu 3+ luminescence spectra. The bandgap width is shown to nonlinearly depend on the solid solution composition. The model explaining this effect is proposed.