Ce/Mn/Cr: (Re,Y)(3)Al(5)O(12) Phosphor Ceramics (Re = Gd, Tb and Lu) for White LED Lighting with Significant Spectral Redshift and Improved Color-Rendering Index

In order to attain phosphor ceramics with a high Color-Rendering Index (CRI), samples with the composition of Y(0.997−x)Re(x)Ce(0.003))(3)(Al(0.9748) Mn(2+)(0.024)Cr(3+)(0.0012))(5)O(12)(Re(x) = 0, Gd(0.333), Gd(0.666), Gd(0.997), Tb(0.333), Tb(0.666), Tb(0.997) and Lu(0.997) were prepared by solid-state reaction and vacuum sintering, and exhibited potential for high-quality, solid-state lighting. Doping with Cr(3+) and Mn(2+) effectively enhanced the red component of Ce(3+) spectra through the intense energy transfer from Ce(3+) ions to Mn(2+)/Cr(3+) ions. The crystal field splitting of [GdO(8)] and [TbO(8)] was more extensive than that of [YO(8)], causing a massive redshift in the Ce(3+) emission peaks from 542 to 561 and 595 nm, while [LuO(8)] had an opposite effect and caused a blueshift with a peak position at 512 nm. White LED devices incorporating Ce/Mn/Cr: (Gd(0.333)Y(0.664))(3)Al(5)O(12) phosphor ceramic exhibited a high CRI of 83.97, highlighting the potential for enhancing the red-light component of white LED lighting.