Tunable warm white light emission and energy transfer of Dy3+ co-doped Sr2LaZrO5.5:Eu3+ phosphors

Eu³⁺,Dy³⁺ co-doped Sr₂LaZrO_5.5-based phosphors were prepared through a sol–gel method. Through characterization, it was found that the Sr₂LaZrO_5.5-based fluorescent powder co-doped with Eu³⁺ and Dy³⁺ had a cubic structure. At an excitation wavelength of 290 nm, the substrate Sr₂LaZrO_5.5 exhibited strong blue emission at 468 nm, and the Sr₂LaZrO_5.5:18%Eu³⁺ phosphor exhibited a strong red emission peak at 612 nm. When the doping amount of Dy³⁺ was 5, 8, 12, 15, or 18%, the Sr₂LaZrO_5.5:18%Eu³⁺ phosphor changed from an orange-red light, to a warm white light, and to a cold white light. According to the emission spectra, the emission intensities of the substrates Sr₂LaZrO_5.5 and Sr₂LaZrO_5.5:Eu³⁺ decreased with increasing Dy³⁺ concentration, confirming the energy transfer between the host Sr₂LaZrO_5.5-Eu³⁺,Dy³⁺, and resulting in a lower CCT value, with significantly improved white light emission.