Clarifying the effect of local structure of Ce3+ and Eu3+ on photoluminescence of YAG:Ce,Eu nanophosphors

A modified sol-gel method was applied in producing Ce3+- and Eu3+- codoped yttrium aluminum garnet (YAG:Ce,Eu) phosphors. Multiple related techniques were utilized to examine the minute correlation between fine structure and photoluminescence (PL) in Ce3+,Eu3+- codoped YAG phosphors in detail. It shows that the Ce3+ or Eu3+ replacement of Y3+ can slightly enlarge the YAG lattice and cause the fine variation of local crystal structure. Ce3+,Eu3+- codoped YAG phosphors exhibit several sharp and narrow D-5(0) -> F-7(J) (J = 0 - 4) red emissions of Eu3+ and broad 5d(1) -> 4f (F-2(5/2), F-2(7/2)) yellow emissions of Ce3+. The PL intensity of Ce3+,Eu3+- codoped YAG phosphors increases with calcination temperature, while dramatically decreases with increasing the Eu3+-doped concentration from 0.11 to 4.40 at.%. Additionally, the geometrical distortion surrounding Ce3+ introduced by incorporated Eu3+ results in the variation of crystal field. It causes red shift of the PL emission band of YAG:Ce,Eu phosphors. (C) 2020 Published by Elsevier B.V.