Carriers trapping and radiative recombination in Ce, Eu and Pr-doped LiLuF4LiLuF4 crystals

The optical properties of as-grown and X-ray irradiated Ce, Eu and Pr-doped LiLuF4LiLuF4 crystals, prospective for lasers, display panels, fluorescent lamps and scintillation application, are presented. The luminescence of Ce3+Ce3+-doped crystal exhibits the fast radiative spin-allowed dfdf transitions in the UV region, whereas Pr3+Pr3+ containing sample shows the UV dfdf and visible ffff emissions. LiLuF4:EuLiLuF4:Eu reveals the line emission spectrum of Eu3+Eu3+ ions and the band peculiar to Eu2+Eu2+ ion as well. It was found that the X-ray induced absorption bands and the TSL peak positions are independent of the type of RE3+RE3+ impurity due to intrinsic nature of radiation defects. The total radiation damage and TSL spectra are specific for each dopant. The distinctive features of the energy storage in RE-doped LiLuF4LiLuF4 crystals are discussed with respect to redox reaction and level positions of RE ion within the gap.