Synthesis and luminescence characterization of Ce³⁺ activated Y₂CaAl₂MgZr₂O₁₂ garnet phosphor for white light emitting diodes

A series of novel Ce³⁺ activated Y₂CaAl₂MgZr₂O₁₂ phosphors were synthesized via a modified solid-state method. The formation of garnet structure was clearly observed from the XRD studies. The elemental mapping images confirmed the homogeneous distribution of all elements in Y₂CaAl₂MgZr₂O₁₂:Ce³⁺. Y₂CaAl₂MgZr₂O₁₂:Ce³⁺ emitted greenish yellow emission peaking at 530 nm by absorbing blue light of 420 to 460 nm. The greenish yellow emission was due to the 5d-4f transition of Ce³⁺ ions. The optimum photoluminescence intensity was observed for 3 mol% concentration of Ce³⁺ ions. The thermal stability of photoluminescence emission of Y₂CaAl₂MgZr₂O₁₂:0.03Ce³⁺ was also investigated at 300 to 480 K and the activation energy was calculated to be 0.32 eV. Commercial red (Sr, Ca)AlSiN₃:Eu phosphors blended with Y₂CaAl₂MgZr₂O₁₂:0.03Ce³⁺ and coated on blue emitting LED chips to fabricated white light emitting diodes (WLEDs). The electroluminescence spectra of the fabricated WLEDs exhibited pure white chromaticity (0.36, 0.37) with high CRI of 94 and low CCT of 4381 K. The spectral characteristic results indicated a promising garnet phosphor for blue excited white light emitting diode applications. (paper)