Synthesis and photoluminescence properties of LaAlO3:Mn4+, Na+ deep red-emitting phosphor

Abstract

LaAlO3:Mn4+ and LaAlO3:Mn4+, Na+ deep red-emitting phosphors are synthesized by a solid-state reaction method in air. Their crystal structures, lifetimes, and luminescence properties are investigated, respectively. PLE spectrum monitored at 730 nm contains three PLE bands peaking at ~276, 325, and 500 nm within the range 200–550 nm, and PL spectrum with excitation 325 nm exhibits two PL band peaks located at ~703 and 730 nm owing to anti-stokes vibronic sidebands associated with the excited state 2E of Mn4+ ion and the 2E → 4A2 transition of Mn4+ ion, respectively. The optimal Mn4+ doping concentration is ~0.8 mol%. Lifetime of LaAl0.992O3:0.8 %Mn4+ phosphor is ~0.92 ms. Na+ ion as charge compensator can improve obviously the luminescence properties of LaAlO3:Mn4+ phosphor due to the charge compensation. The luminous mechanism of Mn4+ ion is explained by using Tanabe–Sugano diagram of Mn4+ ion in octahedral crystal field. The contents of this paper will be helpful to develop novel Mn4+-doped materials and improve their luminescence properties.