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.