Luminescence and stability of Tb doped CaF2 nanoparticles

Luminescence properties of CaF2:Tb3+ nanoparticles were studied in order to investigate the effect of CaF2 native defects on the photoluminescence dynamics of Tb3+ ions. Incorporation of Tb ions into the CaF2 host was confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. Cross-relaxation energy transfer was observed from the photoluminescence spectra and decay curves upon excitation at 257 nm. However, the unusual long lifetime of the Tb3+ ion as well as the decreasing trend of emission lifetime of the D-5(3) level suggested the involvement of traps, which were further investigated by using temperature-dependent photoluminescence measurements, thermoluminescence and lifetime measurements at different wavelengths. This work highlights the critical role that the CaF2 native defects play in the photoluminescence dynamics of Tb3+ ions incorporated in a CaF2 matrix. The sample doped with 10 mol% of Tb3+ ions was found to be stable under prolonged 254 nm ultraviolet irradiation.

Automated summary

The luminescence properties of CaF2:Tb3+ nanoparticles were investigated to understand the impact of CaF2 native defects on the photoluminescence dynamics of Tb3+ ions. The incorporation of Tb ions into the CaF2 host was confirmed through X-ray diffraction and X-ray photoelectron spectroscopy. Cross-relaxation energy transfer was observed in the photoluminescence spectra and decay curves upon excitation at 257 nm. However, the presence of traps was indicated by the unusually long lifetime of the Tb3+ ion and the decreasing emission lifetime of the D-5(3) level, which was further studied using temperature-dependent photoluminescence measurements, thermoluminescence, and lifetime measurements at different wavelengths. This study highlights the important role of CaF2 native defects in the photoluminescence dynamics of Tb3+ ions incorporated in a CaF2 matrix. The sample doped with 10 mol% of Tb3+ ions exhibited good stability under prolonged 254 nm ultraviolet irradiation.