Spectroscopic Characteristic of Praseodymium Ion-Doped Synthetic Cubic Zirconia Crystal

Doping with specific ions can significantly enhance the optical properties of synthetic cubic zirconia crystals. Among these, praseodymium ion (Pr) doping represents one of the most active areas of current research. However, the spectral features arising from different valence states of Pr ions have not yet been fully elucidated. This study investigated 3 Pr-doped synthetic cubic zirconia samples using a suite of characterization techniques, including LA-ICP-MS, infrared spectroscopy, ultraviolet-visible absorption spectroscopy, photoluminescence excitation and emission spectroscopy, three-dimensional fluorescence spectroscopy, and X-ray diffraction. Peak deconvolution analysis of the experimental data was performed to identify the characteristic spectral signatures of Pr³⁺ and Pr⁴⁺ ions within the yttria-stabilized zirconia (YSZ) crystal lattice. The results indicate that Pr⁴⁺ ions are responsible for a broad absorption band below 450 nm, whereas Pr³⁺ ions give rise to characteristic absorption peaks at 449, 474, 485, 583 nm and 612 nm. In the excitation spectra, the peak at 294 nm is attributed to contributions from both Pr⁴⁺ and Pr³⁺ ions, while the excitation peaks observed at 452, 475 nm and 487 nm are exclusively associated with Pr³⁺. The emission spectra reveal that the primary emission peak positions for Pr³⁺ and Pr⁴⁺ are largely identical; however, Pr³⁺ produces an additional distinct emission peak at 665 nm. Three-dimensional fluorescence spectroscopy further demonstrated that the luminescence centers are consistent across all 3 samples. Notably, due to fluorescence quenching effects, the luminescence intensity of sample B and C decreases with increasing Pr concentration. X-ray diffraction analysis confirms that the crystal structure of all three samples is consistent with the standard reference for YSZ.