A series of tunable emission phosphors of Sm3+, Eu3+ and Mn2+ doped Ba3Tb(PO4)3: luminescence and energy transfer

Abstract

A series of activator Sm³⁺, Eu³⁺, Mn²⁺ ion doped Ba₃Tb(PO₄)₃ phosphors with tunable emitting color were synthesized via the high temperature solid state method. X-ray diffraction, luminescence and fluorescent decay curves were used to characterize the phosphors. The obtained powder crystallizes as a cubic unit cell with the space group Ī43d. Under 377 nm excitation of Tb³⁺, Ba₃Tb(PO₄)₃:Sm³⁺ not only presents ⁵D₄–⁷F_6–3 of Tb³⁺ emission lines but also ⁴G_5/2–⁶H_5/2–9/2 of Sm³⁺ orange emission lines, Ba₃Tb(PO₄)₃:Eu³⁺ contains the emission lines of Tb³⁺ and Eu³⁺ (⁵D₀–⁷F_1–4), and Ba₃Tb(PO₄)₃:Mn²⁺ exhibits the emission lines of Tb³⁺ and ⁴T₁–⁶A₁ orange emission band of Mn²⁺. In addition, the intensities of the red or orange-red emission can be enhanced by tuning the Sm³⁺, Eu³⁺ and Mn²⁺ contents. The intense emission intensities of Sm³⁺, Eu³⁺ and Mn²⁺ ions are attributed to the efficient energy transfer from Tb³⁺ to Sm³⁺, Eu³⁺ and Mn²⁺ ions, respectively, which have been justified through the luminescence spectra and fluorescence decay dynamics. The energy transfer mechanism was demonstrated to be the electric dipole–dipole interaction. For Ba₃Tb(PO₄)₃:Sm³⁺, Ba₃Tb(PO₄)₃:Eu³⁺ and Ba₃Tb(PO₄)₃:Mn²⁺, the best quantum efficiencies are 41.6%, 70.3% and 49.8%, respectively. The properties of the phosphors indicate that they may have potential application in UV-pumped white light emitting diodes.