Doctoral Dissertations

Date of Award

12-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

George K. Schweitzer

Committee Members

David M. Jenkins, Jeffrey D. Kovac, Charles L. Melcher

Abstract

The field of nanomaterials has continued to grow exponentially in recent years, covering a large range of markets and industries. The key feature of nano-scaled materials is that their unique properties are a direct result of their small size. Recent application of these nanomaterials in the further production of highly transparent ceramic materials has led to increased interest in the medical imagining field.Cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce) is considered a promising nanophosphor material for application in this field due to advantageous properties such as its high light yield, high effective atomic number, and relatively fast decay time. Further, the gadolinium aluminum gallium garnet and other related garnet materials offer additional advantages for the production of ceramics, largely due to the ability of the garnet structure to address light scattering phenomena that can reduce transparency in ceramic materials.The overarching goal of this dissertation involves the optimization of the production and size control of nanophosphor materials. Two particular means for synthesis are explored: high-energy ball milling (HEBM) and solution combustion synthesis (SCS). Investigations into the HEBM synthesis illustrated the effects of alterations to various parameters for multiple nanophosphor materials utilizing the silicon nitride, zirconia, and tungsten carbide milling systems. SCS experiments illustrated the role of fuel type and temperature manipulation on the synthesis and morphology of GAGG:Ce and other similar materials. This graduate research material then progressed to the reduction of agglomeration phenomena during synthesis of nanomaterials through the addition of diluents. Diluent chemistry refers to the use of solids, liquids, or other separating material to reduce agglomeration in nanoparticles. This work aids in laying the foundation for future nanophosphor and material research.

Comments

Portions of this document were published in the Journal of the American Ceramic Society (K. A. McDonald and G. K. Schweitzer 2018, 101, 3837-3849, doi:10.1111/jace.15563) and Dalton Transactions (K. A. McDonald, et al., 2018, 47, 13190-13203, doi:10.1039/c8dt00637g).

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