Origin of Spectral Blue Shift of Lu3+-Codoped YAG:Ce3+ Phosphor: First-Principles Study

摘要

Lu~(3+), with the smallest ionic radii in lanthanide ions, is an important and beneficial cation for tuning spectrum shifting toward a longer wavelength by ion substitution in many phosphors for solid-state lighting. However, in the Lu~(3+)-substituted garnet system, the phosphor always has smaller lattice parameters and exhibits a shorter emission wavelength than other garnet phosphors. The mechanism of such a spectral blue shift induced by the Lu~(3+)-codoped garnet phosphor is still unclear. In this study, the local and electronic structures of Lu~(3+)-codoped and Lu~(3+)-undoped YAG:Ce~(3+) phosphor have been studied by first-principles calculation to reveal the origin of the spectral blue shift. Our results provide a full explanation of the experimental data and the methodology, which is useful to understand and design garnet phosphors with tunable emission characteristics.