Stability enhancement and photoluminescence modulation in Ca3Al2O6:Ce3+ phosphor via ionic pair substitution strategy

White light-emitting diodes (WLEDs) have emerged as a leading technology for healthy lighting and advanced displays. Nevertheless, the poor thermal stability of blue-emitting components remains a significant bottleneck, hindering their broader adoption in demanding environments. Here, we have prepared a series of Ca 3 Al 2 O 6 :Ce 3+ phosphors by high temperature solid-state method. Substituting the [Al 3+ –O 2- ] ionic pair with [Si 4+ –N 3- ] in the Ca 3 Al 2 O 6 host lattice via a charge-compensated strategy achieves a 1.75 times enhancement in thermal stability compared to the pristine material, while simultaneously inducing a blue-shifted emission spectrum (Δλ = 30 nm). The enhanced thermal stability originates from increased lattice rigidity, while the blue spectral shift arises from modulated crystal field splitting decrease. These mechanistic insights provide a foundational strategy for designing ultra-stable blue phosphors compatible with high-power WLED applications.