Sol–gel Pechini synthesis and optical spectroscopy of nanocrystalline La2O3 doped with Eu3+

Europium-doped La₂O₃ nanocrystalline powders with sizes in the range of 50-200 nm have been obtained by the modified sol-gel Pechini method. Differential thermal analysis, thermogravimetric analysis, infrared spectroscopy and X-ray diffraction were used to study the evolution of the precursor powders towards the desired crystalline phase. We determined the size and the morphology of the nanoparticles by electronic microscopy. Finally, we studied and analyzed the luminescence properties of the trivalent europium in the hexagonal La₂O₃ nanocrystals by photoluminescence and cathodoluminescence. The luminescence spectrum of Eu³⁺ in these nanocrystals is dominated by the ⁵D₀ → ⁷F₂ transition with its maximum intensity peak located at 626 nm, which makes of these nanocrystals promising nanophosphors emitting in the red region of the electromagnetic spectrum.