Spectral tuning of K1-xNaxAl11O17: 0.06Eu2 + phosphors induced by crystal lattice engineering and its application in high color rendering full spectrum WLED

In order to explore the potential application of rare earth doped luminescent materials in illumination display, (K 1- x Na x ) 0.94 Al 11 O 17 : 0.06Eu 2+ (KNAO: Eu 2+ )(0.0 ≤ x  ≤ 1.0) phosphors with tunable spectrum were synthesized by high temperature solid-state reaction. Through X-ray diffraction(XRD), Scanning electron microscope(SEM), Energy dispersive X-ray spectroscopy(EDS), X-ray photoelectron spectroscopy(XPS) and other characterization means, it is confirmed that Na + can enter the matrix lattice by substituting K + ions, and cause unit cell shrinkage. Spectral analysis indicates that with the increase of Na + content, the emission peak of Eu 2+ redshifts from 443 nm to 490 nm, and the FWHM broadens from 41.1 nm to 94.7 nm, thus realizing continuous controllable tuning from blue light to cyan light, and effectively compensation for the "cyan light defect" in the luminescence spectrum. Theoretical calculation reveals that this phenomenon is due to the enhancement of crystal field splitting energy by Na + substitution and the centroid shift caused by the decrease of anion polarizability. Thermal stability studies show that the fully substituted sample exhibits near-zero thermal quenching (99.33 %@423 K), and its thermal quenching activation energy (0.483 eV) is significantly higher than that of the unsubstituted sample (0.270 eV). WLED devices were fabricated by packaging the optimized components (K 0 Na 1 ) 0.94 Al 11 O 17 : 0.06Eu 2+ , Ca 9 KMn(PO 4 ) 7 : 0.03Eu 2+ , and KAl 11 O 17 : 0.04Mn 2+ with 365 nm chip. The color rendering index was 73.5, the correlated color temperature was 4308 K, and excellent color stability was shown in the range of 50–700 mA forward bias current. Compared with commercial WLED, this material has strong luminous continuity in cyan band and significantly improved color restoration ability, which provides a new candidate material for developing full-spectrum lighting devices with high color rendering.