Ln3Al5O12:Mn4+ (Ln = Y and Lu): non-rare-earth doped red phosphor for improving light properties of white light emitting diodes

We fabricated a series of Y 3 Al 5 O 12 :Mn 4+ and Y 1−y Lu y Al 5 O 12 :Mn 4+ phosphors by a solid state reaction. The phase and the optical properties of the synthesized phosphors were investigated. Under the excitation at 465 nm, Y 3 Al 5 O 12 :Mn 4+ phosphors show emission bands locating at deep red regions, which is induced by the spin- and parity-forbidden 2 E g → 4 A 1g transitions of Mn 4+ . The substitution of Y 3+ by Lu 3+ decreases the lattice parameter and thus strengthens the crystal field strength, which gives rise to the blue shift of emission band for Y 1−y Lu y Al 5 O 12 :Mn 4+ phosphors. Due to the compensation of red light by Y 3 Al 5 O 12 :Mn 4+ or Y 1−y Lu y Al 5 O 12 :Mn 4+ phosphor, the values of correlated-color-temperature for fabricated LEDs are decreased, which leads to the suitable application for them in indoor illumination.