Y3Al5-xGaxO12:Cr3+: A novel red persistent phosphor with high brightness

We report on red persistent phosphors of Y3Al5-xGaxO12:Cr3+ garnet (YAGG:Cr3+, x from 0 to 5). In these materials, Cr ions act as both emission centers and electron traps. The trap depth, which is regarded as the energy gap between the bottom of the conduction band and the electron trap, can be optimized by modifying the Ga3+ substitution content (x). After ceasing UV illumination, the persistent luminescence of the YAGG:Cr3+ (x = 3) phosphor was nearly 5 times higher than that of the widely used ZnGa2O4:Cr3+ red persistent phosphor. Such novel red persistent phosphors have great potential for an improved in vivo bioimaging application. (C) 2015 The Japan Society of Applied Physics