Tailoring the photoluminescence properties of lanthanum strontium aluminate phosphors by controlling crystal field environment with fluorine ions

Abstract A series of novel lanthanum strontium aluminate phosphors, Ce 3+ -doped LaSr 2 AlO (5–0.5 x ) F x (LSAF) phosphors were successfully synthesized using the high-temperature solid state synthesis procedure under reducing atmosphere (H 2 /N 2 =1/4). The X-ray diffraction pattern revealed that LSAF sample was a pure LaSr 2 AlO 5 phase with a sintering temperature of 1250 °C. With the increasing amount of SrF 2 , the particle size of powders increased and the shape of particles changed more regularly. Being an orange/red emitting phosphors for orange and white light emitting diodes, LSAF:Ce 3+ could be effectively excited by blue lights with typical 4f→5d transitions of Ce 3+ ions. PL and PLE spectra showed inhomogeneous enlargement effects with the increase of F/O ratios, which suggested that electronegativity effect was promoted when F/O ratio increased. This was further confirmed by a red shift of PL spectra peak when F/O was increased. It can be concluded that the LSAF:Ce phosphors have the potential to meet the development of white light-emitting diodes.