Author ORCID Identifier
https://orcid.org/0000-0002-7014-5825
Defense Date
2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Mechanical and Nuclear Engineering
First Advisor
Jessika V Rojas
Abstract
Lanthanide-doped nanomaterials are emerging as versatile platforms for advanced theragnostic and radiological applications, including medical imaging, radiation therapy, sensing, energy harvesting, and nuclear safety. Their tunable luminescence emission and robustness under ionizing radiation make them promising candidates for next-generation scintillator materials. However, significant challenges remain in optimizing radioluminescent efficiency, structural stability, and host-matrix versatility.
This dissertation addresses these challenges through the design, synthesis, and systematic optimization of multifunctional luminescent nanomaterials. Nanoparticles based on GdPO₄ and LaPO₄ host matrices were doped with Eu³⁺, Tb³⁺, Dy³⁺, and Gd³⁺, exhibiting tunable radioluminescence under X-ray excitation with emissions spanning the 300–700 nm range. Radioluminescence was strongly dependent on dopant concentration, while continuous irradiation studies confirmed remarkable structural and optical stability under high absorbed radiation doses.
Surface-functionalized LaPO₄:Tb³⁺ nanoparticles decorated with Ru, Pd, and Au demonstrated dual functionality for radiosensitization and radiocatalysis. Although surface quenching initially reduced luminescence intensity, core–shell architectures mitigated energy migration to the surface, preserving optical performance. In parallel, surface-decorated structures exhibited enhanced radiocatalytic activity toward methylene blue degradation, with Au-functionalized nanoparticles showing the highest catalytic efficiency. Cytotoxicity studies revealed minimal toxicity and, in some cases, enhanced cell proliferation, supporting their potential for safe theragnostic applications.
Thermal annealing was further investigated as a strategy to enhance the radioluminescent response of GdPO₄:Ln³⁺ nanoparticles. Annealing improved crystallinity, reduced non-radiative defect centers, and induced a phase transformation from hydrated rhabdophane to crystalline monazite. These thermally optimized nanoparticles were subsequently embedded into glass composites, producing intense red, green, and blue emission under X-ray excitation and demonstrating the feasibility of robust scintillating glass materials.
Finally, the potential of these luminescent nanomaterials for therapeutic radioisotope production was explored. Inkjet printing parameters were optimized to control film morphology and ligand–nanoparticle interactions, using lanthanides as non-radioactive surrogates for actinides to better understand surface chemistry and fabricate high-quality nuclear target films for isotopes of medical and industrial relevance.
Overall, this work establishes a comprehensive framework for the development of lanthanide-based nanomaterials with tunable and stable radioluminescence through the optimization of chemical composition, crystal phase, and surface chemistry. The findings provide fundamental insights into the relationships among host matrix selection, dopant composition, surface engineering, and thermal processing, paving the way for next-generation scintillators, radiocatalysts, and multifunctional nanoplatforms that integrate diagnostic and therapeutic capabilities.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-12-2026
Included in
Nanomedicine Commons, Nanoscience and Nanotechnology Commons, Nuclear Engineering Commons