Characterization of Srβ-alumina prepared by sol–gel and spray pyrolysis methods

Eu2+ doped β-alumina, Sr1−xMgAl10O17 Eux2+ (x=0.01–0.07) were successfully prepared by sol–gel and spray pyrolysis techniques with the same precursor materials. Srβ-alumina doped with Eu2+ (SrMgAl10O17:Eu2+) prepared from sol–gel method showed three photoluminescence (PL) peaks at 390, 418 and 459 nm after excitation wavelength at 254 nm and one PL peak at 461 nm when excitation was at 365 nm. The same powder was prepared from spray pyrolysis technique showed the six PL peaks at 323, 397, 415, 443, 480 and 508 nm after excitation at 254 nm. Also two PL peaks at 440 and 480 nm were observed after the excitation at 365 nm. These PL peaks were dependent on the excitation wavelength. The effect of different annealing temperatures of sol–gel powders, preparation conditions of spray pyrolysis powders and reduction atmospheres of both sol–gel and spray pyrolysis powders of various compositions of Eu2+ doped Srβ-alumina were also studied. Both the powders were characterized by scanning electron microscopy, X-ray diffraction and PL techniques and comparison between the two preparation methods. Sol–gel prepared powder had eight times higher PL intensity and brightness than the spray pyrolysis prepared powder. The suggested good composition of Srβ-alumina is Sr0.93MgAl10O17:Eu0.07 for both sol–gel and spay pyrolysis methods.