Elucidating the electronic structures and photoluminescence properties of single-phase ScF3:Dy3+, Eu3+, Ce3+ phosphors for LEDs

A series of single-component ScF 3 :Dy 3+ , Eu 3+ , Ce 3+ phosphors prepared by means of microwave hydrothermal method were explored for light-emitting diodes. The as-prepared samples were characterized via X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence (PL) spectroscopy. In order to rationalize the experimental results, first-principle calculations based on density functional theory had been carried out to discover electronic structures. PL performance of the RE 3+ -doped phosphors exhibited well-defined bands in the visible region. By adjusting the ratios of Ce/Dy/Eu, the color of the as-prepared phosphors can vary from blue (0.24, 0.23) to red (0.51, 0.30) across the white (0.34, 0.26) region according to the chromaticity coordinates. The results suggested that the Dy/Eu/Ce-doped ScF 3 might act as down-convert phosphors for near ultraviolet light-emitting diodes, especially for white LEDs. What is more, it can also promote a deep comperhension of the relationship between structure and properties in ScF 3 -based phosphors. ScF 3 :RE 3+ phosphors with alterable bandgaps can emit light from blue to orange–red across white under the excitation of near ultraviolet light. Introduction of rare earth ions induced the variation of energy band structures in ScF 3 -based phosphors because of the existence of f , p , and d orbits in RE 3+ , therein f and p orbits of RE 3+ made the band structure downwards, the p hybridizing with Sc-3 d promoted the band toward high-energy region.