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

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 MIV2MIIIMII2Al3O12:Ce3+, MIV2MIAl5O12:Ce3+, and MIVMIIIMIIAl5O12: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.