The article, Light Emission Intensities of Luminescent Y₂O₃:Eu and Gd₂O₃:Eu Particles of Various Sizes, can be read here.

This research shows that there is a size effect which is not dependent on the calcination temperature. Ultimately, with increasing particle diameter there is an increase in emitted light, and dense particles emit more light than porous particles.

Rare earth oxides are widely studied and used in a variety of practical, everyday applications. The size of particles also determines their effectiveness. Smaller particles, for instance, are considered to improve the resolution in display technology. The phosphor coatings of lamps, cathode ray tubes, and cathodoluminescence or X-ray intensifying screens are also specifically made with micron-sized particles. The morphological characteristics of the particles thus have an important impact on their practical use. This research explores more closely how and to what extent the size of particles plays a role in their luminescent behavior.