Photoluminescence imaging of europium (III)-doped γ-Al₂ O₃ nanofiber structures

Aluminium oxide (Al₂ O₃ ) has widely been used for catalysts, insulators, and composite materials for diverse applications. Herein, we demonstrated if γ-Al₂ O₃ was useful as a luminescence support material for europium (Eu) (III) activator ion. The hydrothermal method and post-thermal treatment at 800°C were employed to synthesize Eu(III)-doped γ-Al₂ O₃ nanofibre structures. Luminescence characteristics of Eu(III) ions in Al₂ O₃ matrix were fully understood by taking 2D and 3D-photoluminescence imaging profiles. Various sharp emissions between 580 to 720 nm were assigned to the ⁵ D₀ →⁷ F_J (J = 0, 1, 2, 3, 4) transitions of Eu(III) activators. On the basis of X-ray diffraction crystallography, Auger elemental mapping and the asymmetry ratio, Eu(III) ions were found to be well doped into the γ-Al₂ O₃ matrix at a low (1 mol%) doping level. A broad emission at 460 nm was substantially increased upon higher (2 mol%) Eu(III) doping due to defect creation. The first 3D photoluminescence imaging profiles highlight detailed understanding of emission characteristics of Eu(III) ions in Al oxide-based phosphor materials and their potential applications.