Effects of SrCl2 as a flux on the structural and luminescent properties of SrAl2O4:Eu2+, Dy3+ phosphors for AC-LEDs

SrAl2O4:Eu2+, Dy3+ phosphors were prepared by a high temperature solid state reaction method. SrCl2 with various amounts was used as a flux to improve the optical properties of SrAl2O4:Eu2+, Dy3+ phosphors. The crystal structure, particles size, optical properties and decay curve of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra, respectively. It is revealed that the addition of SrCl2 flux can alter the morphology and then improve the photoluminescence of the phosphors. Compared to the commercial phosphors obtained by 0.6% H3BO3, maximum improvement of 13.56% is achieved in the integrated emission intensity of the phosphors when the amount of SrCl2 is 9%. Meantime, the average lifetime of this phosphor can be shorten from 845.86 ms to 428.83 ms. It can be indicated that the phosphor prepared with 9% SrCl2 is more suitable for applications in AC-LEDs with a time gap of 5-20 ms. The results are also confirmed by the fabricating and characterizing LEDs with SrAl2O4:Eu2+, Dy3+ phosphors. These findings show that SrCl2 is an excellent flux for the synthesis of SrAl2O4:Eu2+, Dy3+ phosphors.