Eu3+-activated SrMoO4 phosphors for white LEDs applications: Synthesis and structural characterization

Abstract

We report the synthesis of Eu3+-activated SrMoO4 phosphors by the facile nitrate–citrate gel combustion method. Powder XRD and Rietveld refinement data confirmed that these phosphors have a monophasic scheelite-type tetragonal structure with space group I41/a (No. 88). FESEM micrographs indicate the agglomerated spherical particles. FTIR spectra showed four stretching and bending vibrational modes (2Au and 2Eu). UV–Visible absorption spectroscopy illustrated that the optical band gap energy (Eg) values increase with increase in Eu3+ concentration. The host SrMoO4 phosphor exhibited an intense blue emission under UV excitation (368nm). The Eu3+-activated SrMoO4 phosphors revealed characteristic luminescence due to Eu3+ ion corresponding to 5D1→7FJ (J=1,2) and 5D0→7FJ (J=1,2,3,4) transitions upon 465nm excitation. The electric dipole transition located at 615nm (5D0→7F2) was stronger than the magnetic dipole transition located at 592nm (5D0→7F1). Intensity parameters (Ω2,Ω4) and radiative properties such as transition probabilities (AT), radiative lifetime (τrad) and branching ratio (β) of Eu3+-activated SrMoO4 phosphors were calculated using the Judd–Ofelt theory. Based on the CIE chromaticity diagram, these phosphors can be promising materials for the development of blue and orange–red component in white LEDs.