Search

In this study, a series of Eu3+‐doped silicate xerogels with modified initial compositions is prepared and heat treated at 350 °C to fabricate glass‐ceramic materials containing CaF2 nanocrystals. The impact of an N,N‐dimethylformamide (DMF) additive and a catalyst agent (CH3COOH, HNO3) on the sol–gel transformation from liquid sols through silicate gels and xerogels into glass‐ceramics is investigated using infrared spectroscopy. To verify the formation of CaF2 nanocrystals, X‐ray diffraction (XRD) measurements are performed. The optical behavior of Eu3+ ions in the prepared sol–gel materials is evaluated based on photoluminescence excitation (PLE) and photoluminescence emission (PL) spectra as well as luminescence decay analysis. The distribution of Eu3+ ions between the amorphous silicate hosts and CaF2 nanocrystals in the prepared glass‐ceramic samples is found due to the biexponential character of registered decay curves. In addition, R/O‐ratio (R/O is defined as ratio I(D50‐F72)/I(D50‐F71) analysis is conducted to characterize the efficiency of Eu3+ ion migration into precipitated CaF2 nanocrystals. The lack of DMF as well as HNO3 as a catalyst in the initial composition significantly promotes the incorporation of Eu3+ ions into CaF2 nanocrystals, resulting in long‐lived luminescence with an estimated lifetime τ(D50) = 12.84 ms. [ABSTRACT FROM AUTHOR]