Structural characterization and photoluminescence in the rare earth-free oxy-fluoride anti-perovskites Sr3−xBi2x/3AlO4F and Sr3−xBi2x/3GaO4F

Abstract

The activator Bi³⁺ has been successfully incorporated into the anti-perovskite oxy-fluoride host lattice Sr₃MO₄F (M = Al, Ga) to form rare earth-free phosphors of the composition Sr_3−xBi_2x/3AlO₄F, 0 ≤ x ≤ 0.1, and Sr_3−xBi_2x/3GaO₄F, 0 ≤ x ≤ 0.048. These phases absorb in the UV region (λ_ex = 240–326 nm) and exhibit broad emission in the blue region of the visible spectrum (λ_em = 446.5–455 nm). The optimum compositions for maximum photoluminescent intensity were determined to be Sr_2.976Bi_0.016AlO₄F and Sr_2.976Bi_0.016GaO₄F before concentration quenching occurs. Full structural characterization based upon PXRD and NPD data were performed with DFT calculations suggesting that Bi³⁺ ions are preferentially incorporated on the ten coordinate Sr(1) site.