Intense red emission from Sr4Nb2O9:Eu3+ phosphor by introducing with SrF2 as flux and charge compensator

Sr4Nb2O9:Eu3+ phosphors were prepared by flux method. SrF2 was found to be the appropriate flux and its effect on the crystal structure and optical properties were investigated. The structure of Sr4Nb2O9:Eu3+ has been determined by X-ray powder diffraction with Rietveld refinement. The optimal Eu3+ doping concentrations and the SrF2 usage in Sr4Nb2O9 were determined to be 0.13 mol and 5 wt% respectively. The spectra analysis indicated that the phosphors could be excited by near UV light of 394 nm and blue light of 465 nm, and yield an intense red light with a maximum at 614 nm. The as prepared phosphor shows its advantages in quantum yield and thermal stability when compared with that of CaMoO4:Eu3+, Y3Al5O12:Ce3+, CaAlSiN3:Eu2+ phosphors. Finally, a white LED with improved Ra (from 75.6 to 82.5) was fabricated by using a 450 nm blue chip with Y3Al5O12:Ce3+ and the as-prepared Sr4Nb2O9:0.13Eu3+, 0.05SrF2 phosphor. •Sr4Nb2O9:Eu3+ phosphor was synthesized by flux method.•Sr4Nb2O9:Eu3+ presented red light emission under UV light excitation.•Sr4Nb2O9:Eu3+ have high PL intensity and internal quantum efficiency.