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 Ca₃Sc₂Si₃O₁₂:Ce³⁺ is synthesized and a non-stoichiometric ratio strategy is adopted to improve the luminescence property. Additional Sc³⁺ ions are added into the lattice, and a series of Ca_2.99Ce_0.01Sc_2 + xSi₃O_12 + δ phosphors are prepared. X-ray diffraction patterns exhibit unnoticeable variation though 6 mol% Sc³⁺ is appended. As a consequence, the emission intensity of Ce³⁺ in the lattice is improved. The optimized phosphor Ca₃Sc_2.04Si₃O_12 + δ:Ce³⁺ 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.