LiGaTiO4:Mn4+ red phosphor: Synthesis, luminescence properties and emission enhancement by Mg2+ and Al3+ ions

Novel LiGaTiO 4 :Mn 4+ and LiGaTiO 4 :Mn 4+ , R (R=Mg 2+ and Al 3+ ) phosphors are synthesized by solid-state reaction method in air. Emission spectra of LiGaTiO 4 :Mn 4+ phosphor with excitation 330, 395, and 470   nm contain three emission bands peaking at ~668, 680, and 696   nm in the range of 610–800   nm, and excitation spectrum monitored at 668   nm contains broad excitation band with three excitation peaks located at ~330, 395, and 480   nm within the range 250–600   nm, which indicate that LiGaTiO 4 :Mn 4+ phosphors can be effectively excited by ultraviolet, near ultraviolet, and blue light-emitting diode chips. The optimal Mn 4+ doping concentration is ~0.6   mol% in LiGaTiO 4 :Mn 4+ phosphor. Time resolved luminescence spectra and these lifetime data indicate that it is only a single type of Mn 4+ ion luminescent center in LiGaTiO 4 :Mn 4+ phosphor. Emission intensity of LiGaTiO 4 :Mn 4+ phosphor may be enhanced 1.3–2.2 times by co-doping Mg 2+ and Al 3+ ions. The luminous mechanism of Mn 4+ ion is analyzed by Tanabe-Sugano energy diagram and configurational coordinate diagram.