Efficient and stable cyan phosphor Ca₂LuZr₂Al₃O₁₂:Ce³⁺ for full-spectrum LEDs

Full-spectrum light-emitting diodes (LEDs) are considered as the next health lighting sources, while the cyan gap severely affects the color rendering index (CRI) (Ra < 95). In this work, a series of Ce 3+ -doped Ca 2 GdZr 2 Al 3 O 12 , Ca 2 LuHf 2 Al 3 O 12 , Ca 2 GdHf 2 Al 3 O 12 , and Ca 2 LuZr 2 Al 3 O 12 cyan phosphors were synthesized successfully, in which Ca 2 LuZr 2 Al 3 O 12 :Ce 3+ is well matched with the 410 nm LED chip and emits a bright cyan light (centered at 490 nm) with an excellent external quantum efficiency (EQE = 55%) and good thermal stability (I 423 K /298 K = 72%). Based on the first-principles theory calculations, the excellent EQE and good thermal stability were contributed to the large bandgap and high structural rigidity. Finally, a high performance full-spectrum white LED (w-LED) device was fabricated, which achieved a high color rendering index (Ra = 96.4) and a low correlated color temperature (CCT = 4358 K).