科研之友
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摘要
Two new CF3-substituted beta-diketonates, prepared through Sonogashira coupling reaction and Claisen condensation reaction, were used to synthesize the corresponding antenna europium(111) ternary complexes using 1,10-phenanthroline as an ancillary ligand. These two complexes exhibit a good thermal stability from thermogravimetric analysis. Photophysical properties such as FT-IR spectra, UV-Vis absorption spectra, excitation and emission spectra, luminescence decay curves and quantum yields based on the complexes were investigated and compared. Significantly, quantum yield (0.29) of the 4-F substituted complex is approximately seven times higher than that (0.04) of the unsubstituted one, which indicates the 4-F substituted beta-diketonates ligand is a better candidate for sensitizing Eu3 ion luminescence. Both complexes show the highest excitation intensity around 395 nm, which is perfectly matched with the emission spectrum of commercial similar to 395 nm-emitting InGaN chips. A bright red light-emitting diode (LED) with an efficiency of 2.641m/W was fabricated by coating the 4-F substituted complex onto a similar to 395 nm-emitting InGaN chip. The emission around 395 nm from the InGaN chip was completely absorbed in the spectrum of the LEDs. Its CIE chromaticity coordinates (x=0.6616, y = 0.3251) based on the emission spectrum are close to the National Television Standard Committee (NTSC) standard value for red color. All the results indicate that the 4-F substituted complex is a promising candidate as red components in fabrication of white light-emitting diode (WLED) with a high color-rendering index.
