Non‐Stoichiometric Strategy Induced Luminescence Improvement of the Cyan‐Emitting Phosphor Ca₃Sc₂Si₃O₁₂:Ce³⁺ for WLED

Phosphors with high efficiency and excellent thermal stability are crucial to the phosphors converted light emitting diodes. Herein, a kind of cyan‐emitting phosphor Ca 3 Sc 2 Si 3 O 12 :Ce 3+ is synthesized and a non‐stoichiometric ratio strategy is adopted to improve the luminescence property. Additional Sc 3+ ions are added into the lattice, and a series of Ca 2.99 Ce 0.01 Sc 2 + x Si 3 O 12 + δ phosphors are prepared. X‐ray diffraction patterns exhibit unnoticeable variation though 6 mol% Sc 3+ is appended. As a consequence, the emission intensity of Ce 3+ in the lattice is improved. The optimized phosphor Ca 3 Sc 2.04 Si 3 O 12 + δ :Ce 3+ shows high quantum efficiency (89.6%), and the emission maintains 80% at 423 K of the initial emission intensity. A white light emission diode (WLED) device fabricated by blending this cyan phosphor, commercial yellow, and red phosphors with the blue chip exhibits a high color rendering index value of 92. All these results confirm the efficiency strategy to improve the emission property of the phosphor and the huge application prospect of this cyan‐emitting phosphor for WLED.