Yellow-to-orange emission from Bi2+-doped RF2 (R = Ca and Sr) phosphors

RF2:Bi (R = Ca and Sr) phosphors were synthesized by solid state reaction method in air and their luminescence properties were investigated. Broad yellow-to-orange emissions peaking at ~550 nm (CaF2:Bi) and ~600 nm (SrF2:Bi) were observed under ~260 nm excitation. The emission centers inRF2:Bi (R = Ca and Sr) phosphors are Bi2+ ions, and the excitation and emission bands ofRF2:Bi (R = Ca and Sr) phosphors can be attributed to 2P1/2→2S1/2 and 2P3/2(1) →2P1/2 transitions of Bi2+ ions, respectively. The phosphors are promising for application in lighting due to broad yellow-to- orange emission.