Red emission generation in Ce3+/Mn2+ co-doping Y3Al5O12 phosphor ceramics for warm white lighting emitting diodes

Y₃Al₅O₁₂:Ce³⁺/Mn²⁺/Si⁴⁺ phosphor ceramics were fabricated by solid state reaction. Red emission is obtained, which is attributed to the Mn²⁺:⁴T₁→⁶A₁ spin-forbidden transition under the excitation of 450 nm via the efficient energy transfer from Ce³⁺ to Mn²⁺.The green emission (535 nm) originating from Ce³⁺ and the orange emission (587 nm) from Mn²⁺ ions were observed. Mn²⁺ ions are more inclined to occupy Al³⁺ octahedral sites and the Si⁴⁺ ions locate in the Al³⁺ tetrahedral sites and their co-doping is for charge compensation. The red emission component in Ce³⁺/Mn²⁺/Si⁴⁺ doping YAG phosphor ceramics is significant for obtaining warm white lighting upon increasing Mn²⁺ concentration under 450 nm excitation. White light emitting diodes were successfully constructed by combining the fabricated ceramics with the GaN blue chips.