One-step synthesis of luminescent YVO₄:Eu³⁺/γ-Al₂O₃ nanocomposites by spray pyrolysis

Spray pyrolysis (SP) easily affords nano or sub-micro phosphor particles even on an industrial scale. However, control of the coordination environment around the emitting ion is inefficient, and the final solid matrix will dictate the symmetry of the emitter. Moreover, the fast heat treatment typical of SP usually results in heterogeneous symmetry sites. This paper aimed to obtain inorganic matrices incorporated with phosphors by SP while keeping the symmetry of the emitting ion unchanged along the pyrolysis process. Nanoparticles consisting of Eu³⁺-doped YVO₄ phosphors with average diameter of 15 nm were prepared by the co-precipitation method and were subsequently incorporated into the alumina matrix by SP, to yield YVO₄:Eu³⁺/γ-Al₂O₃ composite particles with mean size of 600 nm. X-ray powder diffraction confirmed that the vanadate particles were incorporated into the alumina matrix, and that the γ-Al₂O₃ phase emerged. The band due to the ${{VO}_4}^{3+}$ → Eu³⁺ transition intensified as a consequence of the incorporation of YVO₄:Eu³⁺ into alumina—the suppression effects caused by the surface properties of the YVO₄:Eu³⁺ phosphor nanoparticles diminished, while the structure of Eu³⁺ remained unchanged in the matrix. (paper)