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, Tb 3+ doped and Tb 3+ /Eu 3+ co-doped K 3 LuF 6 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 Tb 3+ /Eu 3+ co-doped K 3 LuF 6 samples, both characteristic emission spectra of Tb 3+ and Eu 3+ could be observed and the emission color of the K 3 LuF 6 :0.12Tb 3+ ,xEu 3+ 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 Eu 3+ /Tb 3+ . In addition, the energy transfer mechanism in Tb 3+ / Eu 3+ co-doped K 3 LuF 6 was calculated to be a quadrupole-quadrupole interaction from Tb 3+ to Eu 3+ based on the Dexter's equation.

Improvement of Luminescence Characteristics of ZnGa2O4:Tb3+ Nanophosphors by Ce3+ Codoping

“…7 F J (J = 6, 5, and 4) transitions. [30,31] Because of the forbidden 4f-4f transitions, the intensities of Tb 3 + absorption peaks in the ultraviolet (UV) region are relatively weak and their widths are quite narrow. [32,33] Fortunately, the 4f-5d transition of the Ce 3 + ion has superior absorption in the 250-400 nm spectral range, and energy can be efficiently transferred between Ce 3 + and Tb 3 + ions, providing for effective Tb 3 + ion pumping.…”

“…At the same time, considering the high sensitivity of human eyes to green light, [29] the development of green long afterglow material plays an extremely important role in practical application. Tb 3+ ion, like many other lanthanides, has sharp lines at 479, 544, and 587 nm attributed to 5 D 4 → 7 F J (J=6, 5, and 4) transitions [30,31] . Because of the forbidden 4 f –4 f transitions, the intensities of Tb 3+ absorption peaks in the ultraviolet (UV) region are relatively weak and their widths are quite narrow [32,33] .…”