Synthesis and luminescent properties of trivalent rare-earth (Eu³⁺, Tb³⁺) ions doped nanocrystalline AgLa(PO₃)₄ polyphosphates

Highlights: • AgLa(PO₃)₄:Eu³⁺, Tb³⁺ nanocrystalline phosphors were prepared by a sol–gel process. • The luminescent properties were studies by near-UV excitation. • The intense MD transition indicates the presence of high inversion symmetry site. • These results suggest that the compound is a good candidate for optical applications. - Abstract: The AgLa(PO₃)₄ phosphors activated with trivalent rare-earth (Eu³⁺, Tb³⁺) ions were prepared by a sol–gel synthesis method. The crystal structure of the compound was studied by X-ray diffraction patterns and found to be crystallized in the monoclinic system with a space group P2₁/c, indicating the calculated lattice parameters of a = 10.08 Å, b = 13.12 Å, and c = 7.314 Å. The Fourier-transform infrared spectrum, photoluminescence excitation/emission spectra, and decay curves were examined to study the optical properties. The analysis of the Eu³⁺ ions related emission spectrum revealed the presence of highly symmetric sites for the activator ions. The Tb³⁺ ions related emission spectrum exhibited a ⁵D₃ emission due to the prolonged calcination at high temperatures, which reduces the residual hydroxyl ions. The optical properties show that this host material is suitable for phosphor materials and laser crystals