Sol–gel synthesis of micro and nanocrystalline BaAl2O4:Eu3+ powders and their luminescence properties

• Sol–gel method was successfully applied to obtain an orthorhombic BaAl2O4 doped with Eu3+ ions.
• Prepared compound structures were confirmed by X-Ray diffraction and TEM analysis.
• Unusual spectroscopic properties appeared in luminescence spectra were described.
• A detailed analysis of the luminescence spectra by the Judd–Ofelt theory has been performed.

In this paper, we report the obtention of barium aluminate (BaAl2O4) powders doped with Eu3+ ions by the sol–gel method heat-treated at 900 and 1000 °C for 3 h. XRD patterns indicated that the powders have orthorhombic structure with a high crystallite dispersion. The powders have size at submicron scale. They are a strong red emitting materials when are irradiated by ultraviolet light (250 nm). Measured emission and excitation luminescence spectra demonstrated characteristic spectroscopic properties of Eu3+ ions. Recorded luminescence decays and emission spectra were base for calculation of Judd–Ofelt intensity parameters. A detailed analysis of calculated parameters in connection with observed structural and spectroscopic measurements has been done and described.

The crystal structure of BaAl2O4 consists of corner-connected AlO4 tetrahedra and Ba ions are situated in the channels of this sub-structure. According to this report the P63 structure was not found. Finally, it has been found a direct evidence for broken hexagonal (P6322) symmetry in the form of small nano-domains of the structure and the BaAl2O4 was refined with a orthorhombic, P212121 crystal system.Figure optionsDownload high-quality image (63 K)Download as PowerPoint slide