Tunable full-color-emitting La0.827Al11.9O19.09:Eu2+,Mn2+ phosphor for application to warm white-light-emitting diodes

La 0.827 Al 11.9 O 19.09 : Eu 2 + , Mn 2 + showed three emission bands when excited by ultraviolet light. A blue emission originates from Eu2+, whereas both green and red emissions originate from Mn2+. The luminescent mechanism is explained invoking the energy transfer of Eu2+→Mn2+ and Mn2+(tetrahedralsite)→Mn2+(octahedralsite). This energy transfer was confirmed by faster decay times of the blue and green emissions as energy donors. The emitted color of La0.827Al11.9O19.09:Eu2+,Mn2+ can be easily tailored from blue to red through variations of the Mn2+ content. The white-light-emitting diode fabricated via a combination of an ultraviolet light-emitting diode (λpeak=385nm) with La0.827Al11.9O19.09:Eu2+,Mn2+ showed a warm white light (Tc=3559K).