Near UV excited SrAl2O4:Dy3+ phosphors for white LED applications

Abstract

Strontium aluminate phosphors containing different concentrations of Dy3+ ions (SrAl2O4:Dy3+) were prepared by solid state reaction method by sintering at 1100 °C for 3 h. These phosphors were crystallized into monoclinic structure and well consistent with the JCPDS No. 34−0379. All these phosphors exhibit the characteristic emission transitions such as 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2 corresponding to blue (∼480 nm), yellow (∼572 nm) and red (∼663 nm) regions when excited at 350 nm near UV wavelength. Beyond 1.0 mol% concentration of Dy3+ ions, a luminescence quenching was noticed and it has been assigned to the energy transfer through dipole-dipole interactions at higher concentrations. Due to crystallization into nanophase, the SrAl2O4:Dy3+ phosphors exhibit novel and excellent luminescence properties at 350 nm excitation. The 1.0 mol% of Dy3+ -doped SrAl2O4 phosphor show a quantum yield of ∼9.52%. The experimental results suggest that the SrAl2O4:1.0 mol% Dy3+ phosphor could be the best choice to design white LEDs with bright and intense luminescence.