Synthesis, structure and optical performance of red-emitting phosphor Ba5AlF13:Mn4+

Mn4+-activated cubic phase Ba5AlF13 red phosphors were prepared by the two-step coprecipitation method. The structural and optical features were characterized on the basis of X-ray diffraction (XRD), transmission electron microscopy (TEM), emission and excitation spectra, and luminescence decay curves. The Ba5AlF13:Mn4+ phosphors can be efficiently excited by near-UV to blue light and exhibit bright red emission at around 627 nm, which is assigned to the (2)Eg -> (4)A(2g) transition of the 3d(3) electrons in [MnF6] octahedra. Temperature dependent emission spectra and decay curves from 10 to 550 K were measured to deeply understand the luminescence mechanism of Mn4+ in the Ba5AlF13 lattice. Notably, this novel red phosphor shows excellent anti-thermal quenching behaviour (similar to 700% of emission intensity at 300 K relative to 10 K).