Photoluminescent properties of Sr₂CeO₄ : Eu³⁺ and Sr₂CeO₄ : Eu²⁺ phosphors suitable for near ultraviolet excitation

Abstract

Powder phosphors of 1 mol% Eu³⁺- and Eu²⁺-doped strontium cerium oxide (Sr₂CeO₄) were synthesized by standard solid-state reaction method. Eu³⁺- and Eu²⁺-doped Sr₂CeO₄ phosphors fired at 1100 °C for 2 h were analysed by X-ray diffraction (XRD) and photoluminescence (PL) techniques. The XRD patterns confirm that the obtained phosphors are a single phase of Sr₂CeO₄ composed of orthorhombic structure. Room temperature PL excitation spectrum of air-heated Sr₂CeO₄ : Eu phosphor has exhibited bands at 260, 280 and 350 nm. Whereas the excitation spectrum of Sr₂CeO₄ : Eu phosphor heated under reducing (carbon) atmosphere exhibited single broadband range from 260 to 390 nm. The (PL) emission peaks of both the phosphors at 467 (blue), 537 (green) and 616 nm (red) generate white light under 260, 280 and 350 nm excitation wavelengths. The Commission International de l’Eclairage (CIE) colour coordinates conforms that these phosphors emitting white light. The results reveal that these phosphors are multifunctional phosphors which emit white light under these excitations that they could be used as white components for display and lamp devices and as well as possible good light-conversion phosphor LEDs under near-ultraviolet (nUV) chip.