Composition-Dependent Properties of $\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{L}{\mathrm{a}}_{0.95-\mathrm{x}}\mathrm{T}{\mathrm{b}}_{0.05}{\mathrm{F}}_3$ Nanopowders Tailored for X-Ray Photodynamic Therapy and Cathodoluminescence Imaging

Abstract

This study investigates the synthesis and luminescence behavior of $\mathrm{C}{\mathrm{e}}_{\mathrm{x}}\mathrm{L}{\mathrm{a}}_{0.95-\mathrm{x}}\mathrm{T}{\mathrm{b}}_{0.05}{\mathrm{F}}_3$ nanoparticles with varying $\mathrm{C}{\mathrm{e}}^{3+}$ content. The materials were prepared via a wet chemical route and thermally annealed to improve crystallinity and reduce defects. Phase composition and structural parameters were examined by X-ray diffraction (XRD), while elemental composition was determined by X-ray fluorescence (XRF). Cathodoluminescence (CL) intensity mapping was used to evaluate emission uniformity and monitor the degradation of luminescence under electron beam exposure. Photoluminescence (PL) and radioluminescence (RL) spectroscopy confirmed energy transfer from $\mathrm{C}{\mathrm{e}}^{3+}$ to $\mathrm{T}{\mathrm{b}}^{3+}$ ions. Luminescence intensities were found to depend strongly on both Ce content and thermal treatment. The results contribute to the understanding of defect-related quenching mechanisms and are relevant for the design of rare-earth-based luminescent nanomaterials for biomedical applications.