β- Diketone Eu (Ⅲ) Complex Organic Synthesis And Red Phosphor LED Light

InGaN-based WLED is a kind of new solid-state illumination technologies, theefficiency of which has already surpassed that of traditional incandescent bulbs andfluorescent lamps due to the superior features such as quite low power consumption,long life-time, high efficiency, small volume and low maintenance. WLED can beachieved by incorporation of tricolor phosphors （blue, green and red） with near UVInGaN chips, and the phosphor materials play an important role in WLED. Thecurrent commercial red phosphors for solid-state lighting based on near UV InGaNchips are mainly sulfuric materials, such as Y₂O₂S:Eu³⁺and CaS:Eu²⁺. Unfortunately,these red phosphors exhibit a lower emission intensity than that of the blue and greenphosphors. In addition, their instabilities lead to the harmful decomposition products（such as sulfide gas）. Therefore, it is highly desirable to develop red-emittingphosphors with high luminance and satisfactory chromaticity for WLED applications.In this novel four new CF3-substituted β-diketonates, prepared throughSonogashira coupling reaction and Claisen condensation reaction, were used tosynthesize the corresponding antenna europium（III） ternary complexes using1,10-phenanthroline as an ancillary ligand. These four complexes exhibit a goodthermal stability from thermogravimetric analysis. Photophysical properties such asFT-IR spectra, UV–Vis absorption spectra, excitation and emission spectra,luminescence decay curves and quantum yields based on the complexes wereinvestigated and compared. Significantly, quantum yield （0.29） of the4-F substitutedcomplex is the highest, so far, in the literature, which indicates the4-F substitutedβ-diketonates ligand is a better candidate for sensitizing Eu³⁺ion luminescence. Allthe complexes show the highest excitation intensity around395nm, which is perfectlymatched with the emission spectrum of commercial³95nm-emitting InGaN chips.Four bright red light-emitting diode （LED） was fabricated by coating the complexesonto the³95nm-emitting InGaN chips. The emission around395nm from theInGaN chip was completely absorbed in the spectrum of the LEDs. Their CIEchromaticity coordinates based on the emission spectrum are close to the NationalTelevision Standard Committee （NTSC） standard value for red color.All the results indicate that the4-F substituted complex is a promising candidateas red components in fabrication of white light-emitting diode （WLED） with a high color-rendering index.