Synthesis of Sr2Ta2O7:Eu3+ red phosphor and its luminescence characteristics

A series of novel orange-red emitting tantalate phosphors, Sr 2 Ta 2 O 7 :xEu 3+ (0.01 ≤ × ≤ 0.13) were successfully prepared through the solid-state method at high temperature. Under the excitation of 464 nm, Sr 2 Ta 2 O 7 :Eu 3+ emits orange-red light at 597 nm. The PL spectra of Sr 2 Ta 2 O 7 :Eu 3+ phosphors are ascribed to the 5 D 0  →  7 F J ( J  = 0, 1, 2, 3 and 4) transitions of Eu 3+ ions. The optimal doping concentration of Eu 3+ ions was 9 mol%. The optical bandgap of the host was calculated by ultraviolet-visible diffuse reflection spectra (DRS) with a value of 4.73 eV. The emission intensity of phosphors at 423 K still maintains 92% of that at room temperature, which means the material has excellent thermal stability. The chromaticity coordinates of the Sr 2 Ta 2 O 7 :Eu 3+ located in the orange-red region (0.6403, 0.3585). Various results show that Eu 3+ -doped Sr 2 Ta 2 O 7 phosphors have great potential in the field of phosphor conversion white light-emitting diodes (pc-WLEDs).