Heavy-element substitution simultaneously boosts comprehensive photoluminescence performance of Ce3+-activated garnets toward multifunctional optical applications

Simultaneously boosting comprehensive photoluminescence (PL) performance remains a highly important research target for advanced optical applications of rare-earth activated phosphors. However, relevant effective strategies are rarely reported, because the PL performance is predominantly controlled by electron-phonon coupling (EPC) and dynamic local structural fluctuations around activator sites. Herein, we propose a heavy-element substitution strategy to simultaneously optimize the comprehensive PL performance through stepwise Y 3+ replacement by Lu 3+ in Mg 2 (Y 1- x Lu x ) 2.5 Al 1.5 Si 2 O 12 :0.06Ce 3+ ( x  = 0, 1/3, 2/3, 1; x -Lu:Ce 3+ ) garnet phosphors. This strategy enables precise tracking of the gradual EPC evolution during stepwise local structural modulation. Systematic structural and optical characterizations combined with DFT-based investigations verify that stepwise Lu 3+ -substitution dramatically improves the structural rigidity of the host. The reinforced structural rigidity further effectively suppresses the EPC effect and phonon-assisted nonradiative relaxation. Consequently, simultaneous and gradual enhancements are achieved in spectral intensity (3.05-fold), quantum efficiency (53.3% → 80.5%), thermal stability (intensity at 423 K: 32.0% → 82.4%), and chromaticity stability (chromaticity shift at 423 K: 2.862 × 10 −2 → 0.305 × 10 −2 ). White light-emitting diode fabricated using the optimized 1-Lu:Ce 3+ phosphor in place of commercial Y 3 Al 5 O 12 :Ce 3+ yellow phosphor delivers exceptional warm white luminescence. Moreover, the x -Lu:Ce 3+ ( x  = 0, 1) phosphors with remarkably distinct temperature-dependent PL behaviors can be extend their application to temperature-sensitive anti-counterfeiting and information encryption systems.