Spectroscopic distinction of surface and volume ions in cerium(III)- and terbium(III)-containing core and core/shell nanoparticles

Abstract

Core and core/shell Tb3+-doped CePO4 and LaPO4 nanoparticles have been prepared in an organic solvent mixture. The particles were characterized by X-ray diffraction (XRD), UV-vis absorption spectra, luminescence spectra, and lifetimes. It is shown that the luminescence spectra of Ce3+ and Tb3+ ions at the particle surface differ from those located in the interior of the nanocrystals. The emission of cerium surface ions is red-shifted compared to the emission of ions in the particle center. Tb3+ ions at the surface display strongly broadened emission lines, indicating a variety of different surface sites.