The photoluminescence properties of Dy³⁺and Eu³⁺ co-doped Ca₃Sr₃(VO₄)₄ phosphors

In this work, the combustion method was adopted to compound Ca₃Sr₃(VO₄)₄: xDy³⁺ samples at 900 °C, and Eu³⁺ was co-doped into Ca₃Sr₃(VO₄)₄: Dy³⁺ samples to obtain better luminescent properties such as low correlation color temperature (CCT). The microstructure and photoluminescence characteristics of the prepared phosphors were explored with X-ray diffractometer (XRD), scanning electron microscope (SEM), and photoluminescence (PL) spectroscopy, respectively. The rhombohedral crystal structure was demonstrated by the results of XRD analysis, which were in agreement with the standard Ca₃Sr₃(VO₄)₄ phase. Under near-ultraviolet (NUV) excitation at 387 nm, the emission spectra of Ca₃Sr₃(VO₄)₄: xDy³⁺ samples consist of two characteristic emission peaks centered at 484 nm and 575 nm, corresponding to the magnetic dipole transition ⁴F_9/2 → ⁶H_15/2 (blue emission) and electron dipole transition ⁴F_9/2 → ⁶H_13/2 (yellow emission) of Dy³⁺ ions, respectively. In particular, the CCT values were lowered by the addition of Eu³⁺ ions. The above-mentioned conclusions demonstrate that Ca₃Sr₃(VO₄)₄: Dy³⁺, Eu³⁺ sample possesses a promising prospect for warm white light-emitting diodes (white LEDs) under NUV excitation.