Structural, photoluminescence and thermoluminescence study of novel Li⁺ co-activated lanthanum oxide activated with Dy³⁺ and Eu³⁺ obtained by microwave-assisted solution combustion synthesis

Stimulated luminescence of novel La₂O₃ nanophosphors doped with Dy³⁺ and Eu³⁺ and co-activated with Li⁺, prepared by microwave-assisted solution combustion synthesis, was investigated for the very first time. X-ray diffraction results indicated hexagonal La₂O₃ crystalline phase. Lanthanide and Li⁺ doping did not affect the La₂O₃ crystal structure. Scanning electron microscopy images showed nanoparticle morphologies such as plates, rods and irregular shapes. Photoluminescence spectra of La₂O₃:Dy³⁺, Li⁺ exhibited blue and green emission bands due to Dy³⁺ transitions. For La₂O₃:Eu³⁺, Li⁺, sharp emission lines, corresponding to the optical transitions of Eu³⁺ were observed. Thermoluminescence glow curve of La₂O₃:Dy³⁺, Li⁺ previously exposed to beta radiation exhibited a prominent glow peak located at ∼46 °C, possibly useful for after-glow or persistent luminescence applications, whereas La₂O₃:Eu³⁺, Li⁺ curve, displayed three intense peaks at ∼50, ∼110 and ∼150 °C. Thermoluminescent signal repeatability and decay curve asymptotic behaviour could place La₂O₃:Eu³⁺, Li⁺ as suitable for medium and high-dose radiation dosimetry applications.