Red shifts of the yellow emission of YAG:Ce3+ due to tetragonal fields induced by cationic substitutions

摘要

Wave function theory ab initio embedded cluster calculations show that Ce3+-doped transformed aluminum garnets resulting from Y3Al5O12:Ce3+ after cationic substitutions that enhance the tetragonal field around Ce3+, have their lowest 4f-5d transition red-shifted with respect to the yellow phosphor YAG:Ce3+ used in GaN blue-LED based lighting devices. Red shifts in the range of 1000-3000 cm(-1) are found in 33 transformed garnets of the types (M2MM2Al3O12)-M-IV-M-III-Al-II:Ce3+, (M2MAl5O12)-M-IV-Al-I:Ce3+, and (MMMAl5O12)-M-IV-M-III-Al-II:Ce3+. This result shapes the design of new red phosphors by enhancing the tetragonal field around Ce3+ via cationic substitutions made in Ce3+-doped aluminum garnets.