A comparative study of spectral and luminescent properties of Eu3+-doped cation-deficient perovskite phosphors

Eu 3+ is not only a major red-emitting activator, but also an excellent spectral probe ion. This work reports the Eu 3+ -sites and luminescence in the cation-deficient perovskite tungstates, A-site deficient SrLa 2 (Mg 2 W 2 )O 12 [Sr 1/2 □ 1/2 La(MgW)O 6 ] and B-site deficient Sr 2 La 2 (MgW 2 )O 12 [SrLa(Mg 1/2 □ 1/2 W)O 6 ]. The 7 F 0 → 5 D 0 excitation spectra of Eu 3+ activators in two lattices were measured via pulsed dye laser. In SrLa 2 (Mg 2 W 2 )O 12 :Eu 3+ , there is only one 7 F 0 → 5 D 0 transition, which could be related to the Eu 3+ center on La 3+ sites; while, two 7 F 0 → 5 D 0 transitions in Sr 2 La 2 (MgW 2 )O 12 indicate Eu 3+ ions occupy Sr 2+ in addition to La 3+ , resulting in the luminescent centers related to heterovalent substitution defects. The different Eu 3+ sites make two phosphors exhibit different red luminescence properties. SrLa 2 (Mg 2 W 2 )O 12 :Eu 3+ shows higher luminescent efficiency and thermal quenching due to its regular distribution of the activators resulting in lower dispersion losses of the energy transfer. The experimental results show that rare earth ions occupy different crystallographic positions in A -site and B -site deficient perovskite oxides, and this microstructure can be important for the corresponding luminescent properties.