Structural and optical properties of Ca_0.88TiO₃∶0.12Eu³⁺ red phosphors

Red phosphors of Ca_0.88TiO₃:0.12Eu³⁺ (CTE) were synthesized by solid-state method, and their structure and morphology were studied. XRD results show that CTE phosphors sintered at different temperature exhibit orthorhombic structure. The average grain size increases with the increase of sintering temperature, and their crystallization sintered at 1 300 ℃ is the best, which is consistent with the SEM results. CTE phosphors can be efficiently excited by near-ultraviolet light of 398 nm, and emit intensive red light with peaks around 594 nm and 616 nm corresponding to the transition ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ of Eu³⁺. The peak around 616 nm is stronger than that of 594 nm, showing that Eu³⁺ ions site at lattice without the center of inversion symmetry. The emission intensity of CTE phosphor increases with the sintering temperature, and is the highest when the sintering temperature is 1300℃ due to higher crystallinity. Furthermore, CTE phosphors have very good thermal stability and high color purity, implying the potential to be a promising red phosphor in white light emitting diodes.