The features of morphology and crystalline structure of the monodisperse Lu2O3:Eu3+ submicrospheres prepared by sol–gel method

Monodisperse Lu2O3:Eu3+ submicrospheres with the diameters ranging from 40 to 400 nm were obtained by the urea-based homogeneous precipitation technique with subsequent spheres crystallization during annealing. The inner structure, morphology of Lu2O3:Eu3+ polycrystalline spheres and thermal stability of the particles shape were investigated by means of transmission electron microscopy (TEM), X-ray diffractometry (XRD) and electron paramagnetic resonance (EPR). Eu3+-doped lutetium oxide spheres were characterized by effective luminescence under X-ray excitation in the λ=575–725 nm range corresponding to 5D0→7FJ transitions (J=0–4) of Eu3+ ions. Experimental data showed that the X-ray luminescence efficiency increases with the increase of the crystallites size, which occurred by the annealing temperature and particles diameter.