Principles and applications of rare earth ion-Doped nanoparticles

Abstract

This article presents some fundamental properties of nanoparticles of insulating materials doped with rare earth ions as optically active centers. The optical properties nanoparticle semiconductors are well established; the particle diameter dictates the band gap, and hence the particle’s absorption and emission properties. In the case of insulators, we show that such an effect is unlikely. The optical properties of insulating nanoparticles doped with optically active ions are affected by the particle size mainly through (1) the reduced phonon density of states and (2) the role of the surface sites occupied by the dopant ions. In this article we examine the fundamental physics of these systems, and call attention to experiments in which the effects of particle size have been observed. We also discuss the application of rare earth ion doped nanoparticles to the field of nanothermometry.