Temperature effect on fluorescence and UV–vis absorption spectroscopic properties of Dy(III) in molten LiCl–KCl eutectic salt

Abstract

The spectroscopic properties of Dy(III) in molten LiCl–KCl eutectic salt at high temperature were investigated by time-resolved laser fluorescence spectroscopy (TRLFS) and UV–vis absorption spectroscopy. For the first time, a visible fluorescence of Dy(III) in high-temperature LiCl–KCl eutectic salt was measured due to the electronic transitions from 4I13/2 and 4F9/2 to 6HJ/2 (J=7,…,15). The effect of temperature on hypersensitivity for the electronic transitions from the 4I13/2 excited state (∼25700cm−1) of Dy(III) was confirmed by altering temperature in chloride eutectic salt in accord with optical absorption measurements. The molar absorptivity of 4I13/2←6H15/2 was enhanced with increasing temperature. The fluorescence intensity of Dy(III) followed a simple mono-exponential decay curve, suggesting the formation of a single chemical species in high-temperature LiCl–KCl molten salt.