关键词: CaLa₂(WO₄)₄, 高温固相法, 红色荧光粉, 能量传递, 荧光寿命, 热稳定性, 色度坐标

Abstract: A series of red phosphors of CaLa₂(WO₄)₄∶Eu³⁺ and CaLa₂(WO₄)₄∶Eu³⁺,Sm³⁺ were synthesized by high temperature solid state method. The crystal structure, spectral properties, thermal stability, fluorescence lifetime, and color coordinates of the samples were analyzed by experimental equipment such as X-ray diffractometry and scanning electron microscopy, etc. The results show that the samples synthesized by doping Eu³⁺and Sm³⁺into CaLa₂(WO₄)₄did not contain impurity phases, and the crystal structure remains unchanged. Under the excitation of 394 nm, the CaLa₂(WO₄)₄∶Eu³⁺ phosphors exhibit the strongest red light emission at 615 nm, originating from the ⁵D₀→⁷F₂ electric dipole transition of Eu³⁺. The optimal doping concentration is 0.09. After doping with Sm³⁺, the emission peaks enhance, and the lifetime of the phosphors significantly increases. Sm³⁺ exhibits a sensitizing effect on Eu³⁺. In the co-doped system, energy is transferred from Sm³⁺ to Eu³⁺. For CaLa₂(WO₄)₄∶Eu³⁺,Sm³⁺, as the temperature increases, the integrated area of the ⁵D₀→⁷F₂ transition emission of Eu³⁺ gradually decreases; when the temperature rises to 100 ℃, the luminescence intensity become 53% of the initial temperature, indicating the occurrence of temperature quenching. In the co-doped system, the color coordinates move towards the red light region as the doping amount of Sm³⁺ increases. When the doping amount of Sm³⁺ is 0.02, the corresponding color coordinate is (0.645 8, 0.353 8). Based on the characteristics of CaLa₂(WO₄)₄∶Eu³⁺,Sm³⁺ phosphors, it can be used as potential red phosphors for white LEDS.

Key words: CaLa₂(WO₄)₄, high temperature solid state method, red phosphor, energy transfer, fluorescence lifetime, thermal stability, color coordinate