Hybrid Eu Coordination Luminophore Standing on Two Legs on Silica Nanoparticles for Enhanced Luminescence.

In this study, we have demonstrated a two-legged, upright molecular design method for monochromatic and bright red luminescent Ln -silica nanomaterials. A novel Eu -silica hybrid nanoparticle was developed by using a doubly binding TPPO-Si(OEt) (TPPO: triphenyl phosphine oxide) linker. The TPPO-Si(OEt) was confirmed by H, P, Si NMR spectroscopy and single-crystal X-ray analysis. Luminescent Eu(hfa) and Eu(tfc) moieties (hfa: hexafluoroacetylacetonate, tfc: 3-(trifluoromethylhydroxymethylene)camphorate) were fixed onto TPPO-Si(OEt) -modified silica nanoparticles, producing Eu(hfa) (TPPO-Si) -SiO and Eu(tfc) (TPPO-Si) -SiO , respectively. Eu(hfa) (TPPO-Si) -SiO exhibited the higher intrinsic luminescence quantum yield (93 %) and longer emission lifetime (0.98 ms), which is much larger than those of previously reported Eu -based hybrid materials. Eu(tfc) (TPPO-Si) -SiO showed an extra-large intrinsic emission quantum yield (54 %), although the emission quantum yield for the precursor Eu(tfc) (TPPO-Si(OEt) ) was found to be 39 %. These results confirmed that the TPPO-Si(OEt) linker is a promising candidate for development of Eu -based luminescent materials.