Red-emitting SrIn₂O₄: Eu³⁺ phosphor powders for applications in solid state white lamps

Red-emitting phosphor powders of SrIn₂O₄ activated with Eu³⁺ ions were fabricated by high pressure assisted combustion synthesis. X-ray diffraction analysis of these oxide phosphors revealed the formation of single-phase orthorhombic SrIn₂O₄ for concentrations up to 4 at% Eu. A detailed photoluminescence (PL) and cathodoluminescence study showed bright red emission originated within the ⁵ D₀ → ⁷F_J intra-shell transitions of Eu³⁺. Furthermore, PL excitation spectroscopy revealed that an efficient energy transfer from the SrIn₂O₄ host lattice onto the Eu ions is accomplished in addition to the excitation band peaked at 396 nm that directly excites the Eu ions, making this material an excellent candidate for applications in solid state white lamps.