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

La0.827Al11.9O19.09:Eu2+,Mn2+ 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+(tetrahedral site)-> Mn2+(octahedral site). 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 (lambda(peak)=385 nm) with La0.827Al11.9O19.09:Eu2+,Mn2+ showed a warm white light (T-c=3559 K). (c) 2006 American Institute of Physics.