Radiative properties of Er3+ doped and Er3+/Yb3+co-doped Sr3Al2O6 phosphors: exploring the usefulness as a phosphor material

Alkaline earth metal ion based aluminates have been reported to be potential host materials for inorganic phosphors. In this context, the usability of Er doped and Er/Yb co-doped Sr3Al2O6 (SAO) samples was explored. The samples prepared via a soft combustion synthesis route showed no signs of phase separation in the XRD data. The UV–VIS-NIR absorption data suggested the stabilisation of the dopant ions in the trivalent states. The direct and indirect band gaps of the systems evaluated through the Davis-Mott analogy matched with literature values. The Urbach energy values obtained from the absorption data indicated the formation of point defects in the prepared sample. Using Judd–Ofelt methodology in correlation with the optical data, various radiative parameters, such as the intensity parameters, spectroscopic quality factor, transition probabilities, radiative lifetimes, etc. were evaluated. It was observed that in the SAO host, the metal ion was sitting at a more asymmetric site with a higher degree of covalency between the metal–ligand bond. It was further observed that in the samples, absorption of one near infrared photon resulted in the observed infrared emission. From the observed data, we discuss the radiative properties of the system in a systematic way.