Lanthanide-containing Nanostructured Materials

Abstract

The research described in this Dissertation is concerned generally with the exploration of the potential use of lanthanide elements in nanostructured materials for the purpose of modification of the magnetic and optical properties. This is explored through a focus on the development of lanthanide-containing iron oxide nanosystems. Our objectives of producing lanthanide containing nanostructured materials with potentially useful optical and magnetic applications has been achieved through the development of lanthanide-doped Fe3O4 and -Fe2O3 nanoparticles, as well as a unique core-shell magnetic-upconverting nanoparticle system.Necessary background information on nanomaterials, rationale for the study of lanthanide-containing iron oxide nanosystems and context for discussion of the results obtained in each project is provided in the Introduction Chapter. The syntheses of Fe3O4 nanoparticles doped with Eu(III) and Sm(III) are discussed, along with structural characterization and magnetic property investigation of products In Chapter 2. The following Chapter expands the study of lanthanide doping to -Fe2O3, a closely related yet distinct magnetic nanoparticle system. A completely different synthesis is attempted, and comparisons between the two systems are made.The development of novel synthetic methodologies used to create such products has yielded high-quality lanthanide-containing materials and are evidenced by TEM images displaying nearly monodisperse particles in each of our efforts. The modifications to the magnetic properties resulting from lanthanide doping include theobservation of ferromagnetism in the Fe3O4 system and increased magnetic saturation of -Fe2O3 nanoparticles, and are characterized by VSM and the visual observation of magnetic alignment of products. Our efforts towards developing a novel methodology capable of producing high quality Fe3O4 nanoparticles, and subsequent characterization of products, were published in the Journal of the American Chemical Society.Optically active, magnetic, core-shell nanoparticles are investigated in Chapter 4 for the potential uses in diagnosis and treatment of cancer. This multifunctional system uses Fe3O4 as a magnetic core, shelled by upconverting lanthanide-containing nanomaterials, and is rendered biocompatible through encapsulation of the core-shell structure by a silica shell. Added functionality is achieved through amine functionalization of the silica surface, with the goal of coupling the inorganic nanoparticle with drug targeting groups. TEM results indicate successful formation of the core-shell nanoparticles, and expected magnetic and optical properties are shown by visual observation and luminescence spectroscopy, respectively.