Warm-toned, color-tunable, and highly emissive long lasting phosphorescent composite: PMMA/[email protected]₂O₄:Eu²⁺, Dy³⁺

Color-tuned long lasting phosphorescent composite PMMA/[email protected]₂O₄:Eu²⁺,Dy³⁺ (SAOED) with warm-toned phosphorescent color and excellent afterglow properties were prepared by coating PMMA and a red light-emitting coumarin fluorescent dye color converter (RECC) and PMMA on the surface of the green emitting long lasting phosphor SAOED. X-ray diffraction (XRD) patterns show that the crystal lattice of the PMMA/[email protected] samples are identical to the uncoated SAOED. The photoluminescence (PL) emission spectra of the PMMA/[email protected] consist of two broad band ranging from 450 to 575 nm and 576–700 nm, and the spectra intensity in the range of 576–700 nm increased gradually with the increment of RECC. The CIE chromaticity coordinates and the luminescence images of the PMMA/[email protected] samples indicate that the emitting color of PMMA/[email protected] is composed of the phosphorescent color of SAOED and the fluorescent color of RECC, and it exhibits a reddish emitting color with color purity of 0.8726 when the concentration of the RECC was added to 0.9%. Even though the coating layer of RECC has a negative influence on the quantum yield (QY) and afterglow brightness of PMMA/[email protected], the afterglow curves of PMMA/[email protected] are similar in shape with the uncoated SAOED, both of them are fitted well with a third-order exponential equation.