Preparation and luminescent properties of modified phosphors VTES@Ba3ScB3O9: xEu(3+) and its polymer fluorescence films devices

Rare earth red LED devices are widely used in indoor plant lighting, light therapy and other fields owning to their advantages of long life, low cost, energy saving, and environmental protection. However, their practical application is greatly limited due to the serious phenomena of deliquescence and agglomeration. In this work, a series of red-emitting Ba3ScB3O9:xEu(3+) phosphors have been prepared by two-step high-temperature solid state method. Ba3ScB3O9:xEu(3+) phosphors show an orange-red emission at 575-650 nm excited by the wavelength of 244 nm, reaching the maximum at the doping concentration of 0.05. The modified red-emitting phosphors VTES@Ba3ScB3O9:0.05Eu(3+) have been further prepared by surface modification with vinyl triethoxysilane (VTES). The FT-IR, XRD, XPS, and SEM analysis of the VTES@Ba3ScB3O9:0.05Eu(3+) phosphors show that VTES is bonded with Ba3ScB3O9:0.05Eu(3+) successfully. The particle size distribution of phosphors VTES@Ba3ScB3O9:0.05Eu(3+) is uniform, the agglomeration phenomenon is obviously weakened, and the thermal quenching is retarded. The fluorescence films have been prepared by blending phosphors with polymethyl methacrylate (PMMA). The hydrophobicity, thermal stability, and dispersibility in polymer matrix are improved. The fluorescence films have good ultra-violet resistance. It is worthy noted that the luminescent intensity of modified fluorescence films is higher than that of unmodified ones because the non-radiative transition and PL quenching of phosphors are inhibited in the modified fluorescence films. It's very gratifying to see that the brightness of the modified fluorescence films LED devices increases to 1.26 times than that of unmodified ones, and CIE color coordinates shift to red light region.