Remarkable structure and luminescence regulation of a Gd 2 LuAl 5 O 12 :Ce garnet phosphor with a Ca 2+ /Si 4+ pair for high-quality w-WLED lighting.

Doping Gd 2 LuAl 5 O 12 :Ce with a Ca 2+ /Si 4+ pair produced a series of Gd 1.97- x LuCa x Al 5- x Si x O 12 :0.03Ce ( x = 0.0-1.2) garnet new phosphors, and remarkable regulation of the crystal structure and Ce 3+ luminescence was achieved. Rietveld refinement and spectral analysis revealed that greater incorporation of Ca 2+ /Si 4+ led to a higher lattice rigidity by cell contraction, a narrower bandgap, a longer average bond length/less distortion of the [CeO 8 ] dodecahedron and decreased centroid shift/crystal field splitting of the Ce 3+ 5d energy level. A blue-shifted 4f-5d 1 transition, a narrower emission band, improved thermal stability of luminescence and a shorter fluorescence lifetime were observed with increasing Ca 2+ /Si 4+ content. Applying the yellowish-green-emitting Gd 0.77 LuCa 1.2 Al 3.8 Si 1.2 O 12 :0.03Ce optimal phosphor ( x = 1.2), together with a commercial CaAlSiN 3 :Eu red phosphor, in 450 nm-excited LED lighting produced a low CCT of ∼3625 K and a high CRI/R9 of ∼95.2/94.8, indicating that the phosphor has application potential in high-performance w-WLED.