Preparation and luminescent properties of a new red phosphor (Sr4Al14O25:Mn4+) for white LEDs

A new Mn4+ activated (non-RE activated) aluminate based Sr4Al14O25 phosphor was prepared by a solid-state reaction. The crystal structure of Sr4Al14O25:Mn4+ phosphor was characterized by XRD and emission spectrum as well as excitation spectrum of the prepared phosphor was measured. Emission spectrum shows that phosphor can be effectively excited by NUV light source. Simultaneously, emission spectrum measurement shows that the sharp emission peak at 651 nm is ascribed to the 2E → 4A2 transition of Mn4+ ion and a broad band at 662 nm is attributed to the phonon sideband transition. It is found that the quenching concentration of Mn4+ in phosphor is 0.7 mol.%. In the end, the emission spectra of Sr4Al14O25:Mn4+, Cl−/Pb2+ were investigated. Sr4Al14O25:Mn4+ phosphor is expected to be used as a red phosphor in white LEDs because phosphor can be excited by NUV chip.