Abstract

Trivalent europium or erbium doped yttria samples obtained by a wet chemical synthesis procedure have been investigated by wide and small angle X-ray scattering, scanning and transmission electron microscopy and luminescence spectroscopy. On the micron scale the powders obtained are large, compact aggregates built up of platelets about 200 nm large and 10 nm thick, arranged with some degree of order. Platelets are nanocrystals with the cubic structure of yttria and contain randomly distributed pores of 2–4 nm at average distance of about 10 nm. Lanthanide dopants have no noticeable effect on the morphology but cause the lattice parameter of the yttria structure to change in a way proportional to their ionic radius. The luminescence spectrum in the visible region of the Eu³⁺ doped nanocrystals indicates the presence of a high degree of disorder in the environment around the lanthanide ion.