Optical characteristics of samarium doped ZnAl2O4 nanomaterials synthesized by vibrational milling process

Abstract

Optical and fluorescence properties of samarium (Sm) doped zinc aluminate host matrix (Sm:ZnAl2O4) was studied. Sm:ZnAl2O4 nanopowder was synthesized by vibrational milling process assisted with calcination treatment. Structural and optical properties of Sm:ZnAl2O4 nanopowders were investigated via the crucial parameter of different doping concentration. Structural properties of as-synthesized samples and Sm: ZnAl2O4 powders were characterized by X-ray diffraction and scanning electron microscope. For optical properties, Sm: ZnAl2O4 phosphor materials were analyzed via diffuse reflectance and photoluminescence spectroscopy. The preliminary results suggested that Sm: ZnAl2O4 powders were identically in spinel crystalline phase as host ZnAl2O4 structure affirmed by XRD result. SEM images indicated the Sm:ZnAl2O4 after the synthesis distinctly obtained in ultrafine power due to the effect of several milling round and sintering process. The optical properties in reflectance mode of Sm:ZnAl2O4 samples were significantly increased by the presence of Sm dopant in ZnAl2O4 structure. Meanwhile, the luminescent materials showed red emissions under visible light excitation in range of 650-730 nm by PL spectra. The improvement of ZnAl2O4 photoluminescence property was obviously obtained at 0.5 wt.% Sm due to photon transfer from Sm to host material.