Luminescence properties and energy transfer of K3LuF6:Tb3+,Eu3+ multicolor phosphors with a cryolite structure

Abstract

In recent years, compounds with a cryolite structure have become excellent hosts for luminescent materials. In this paper, Tb³⁺ doped and Tb³⁺/Eu³⁺ co-doped K₃LuF₆ phosphors were prepared via a high temperature solid phase sintering method. The XRD, SEM, as well as photoluminescence excitation (PLE) and emission (PL) spectra were measured to investigate the structure and luminescence properties of the as-prepared samples. In the Tb³⁺/Eu³⁺ co-doped K₃LuF₆ samples, both characteristic emission spectra of Tb³⁺ and Eu³⁺ could be observed and the emission color of the K₃LuF₆:0.12Tb³⁺,xEu³⁺ phosphors could be adjusted from green to yellowish pink and the corresponding CIE values could be regulated from (0.2781, 0.5407) in the green area to (0.4331, 0.3556) in the yellowish pink area by controlling the concentration ratio of Eu³⁺/Tb³⁺. In addition, the energy transfer mechanism in Tb³⁺/Eu³⁺ co-doped K₃LuF₆ was calculated to be a quadrupole–quadrupole interaction from Tb³⁺ to Eu³⁺ based on the Dexter's equation.