Luminescence and energy transfer of a color tunable phosphor: Tb3+ and Eu3+ co-doped ScPO4

Abstract

A series of novel emission-tunable ScPO₄:xTb³⁺, yEu³⁺ phosphors were prepared by a high temperature solid-state reaction. The phase purity was examined using X-ray diffraction refinement. X-ray photoelectron spectroscopy (XPS) and the crystal information, luminescence properties and energy transfer between Tb³⁺ and Eu³⁺ are analyzed systematically. The cross relaxation from ⁵D₃ to ⁵D₄ of single doped Tb³⁺ in the host is investigated. The energy transfer between Tb³⁺ and Eu³⁺ has been demonstrated by the decay times, which are ascribed to the dipole–dipole (d–d) mechanism, and the η_T reaches 54.4%. Additionally, the energy transfer critical distance between Tb³⁺ and Eu³⁺ was calculated to be about 12.95 Å. The emission color can be adjusted from green to yellow to orange-red by tuning the ratio of Tb³⁺/Eu³⁺. The ScPO₄:0.03Tb³⁺, 0.025Eu³⁺ exhibits good thermal stability, indicating its great potential in w-LED applications.