An impact of sintering temperature and doping level on structural and spectral properties of Eu-doped strontium aluminium oxide

In the present work, a sol-gel method was employed to prepare nanosized SrAl2O4 powders doped with Eu3+ ions. The raw nanomaterials were thermally treated at 900 to 1100 °C for 3 h. The XRD analysis demonstrated that the powders were single-phase nanopowders with high crystallite dispersion. Our studies were focused on relating the luminescence properties of the Eu3+ dopant to the NC (nanocrystallites) size. This was achieved by varying the calcinations temperature between 900 and 1100 °C. The average NC size varied accordingly between ∼36 and ∼75 nm. We found that size effect manifested mainly in the expansion of the cell volume and broadening of XRD peaks as indicated by Rietveld analysis. Moreover the emission and excitation spectra, although typical for Eu3+ ions, demonstrated some degree of variability with calcinations temperature and doping concentration. To explain these differences a detailed analysis of luminescence spectra by the Judd-Ofelt theory was performed.