Optimising synthesis conditions for long lasting SrAl₂O₄ phosphor

To evaluate the effect of flux, activator and co‐activator on solid state synthesis of SrAl₂O₄: Eu^2 +, Dy^3 + phosphor, where boric oxide, europium oxide and dispersium oxide were used, respectively.

To optimise synthesis condition of long lasting phosphorescence SrAl₂O₄ phosphor, boric oxide was used as a flux. To improve relative intensity of SrAl₂O₄: Eu^2 + phosphor, the critical concentration of Eu^2 + was determined. The effect of various concentration of co‐activator on afterglow properties, the effect of Dy^3 + ion on the emission and excitation spectra were examined.

The SrAl₂O₄: Eu^2 +, Dy^3 + phosphor powders have been synthesised by solid state reaction method. The result of XRD patterns indicated that, addition of 5 mol% B₂O₃ enhanced the formation of SrAl₂O₄ at 1,200°C. Investigation on the variation of emission intensity of different phosphors containing different amounts of Eu^2 + revealed that after 6 mol% of Eu^2 + concentration, quenching process occurred. Dy^3 + formed trap levels and results demonstrated that increasing concentration of Dy^3 + up to 5 mol% reduced the relative intensity and increased the decay time.

Using B₂O₃ as a flux and solid state reaction method for preparation of this phosphor is in good agreement with industrial production and make it economic, because of reduced sintering temperature.