Time-resolved fluorescence spectra of europium methylbenzoates (MBA)with 1,10-phenanthroline(phen)have been measured at room temperature.For each of the europium chelates,where the ligand triple states lie above the ~...Time-resolved fluorescence spectra of europium methylbenzoates (MBA)with 1,10-phenanthroline(phen)have been measured at room temperature.For each of the europium chelates,where the ligand triple states lie above the ~5D_1 level of Eu^(3-),the spectra providc evidence that the Eu^(3-) ~5D_0 state is populated by nonradiative energy transfer from the higher-lying ~5D_1,state.The relaxation time for energy decay from ~5D_1 state is measured in the microcrystals to bc of the order of a few microseconds.It is suggested that the ligand C=0 and C=C stretching vibrations and Eu-O vibrations,chclate ring and benzene ring vibrations make important contributions to the relaxation process.The ~5D\-1—~5D\-0 relaxation time of Eu- (p-MBA)_3phen is shorter than those of Eu(m-MBA)_3phen and Eu(o-MBA)_3phen since nonradiative degradation to ~5D_0 from ~5D_1 appears to be more strongly influenced by the E_u^(3+)sites in the former.展开更多
Novel ordered mesoporous Eu(DBM)3phen/APTES-SBA-15 (EAS) composites with reasonable photoluminescence property and interesting morphology of bundles of pearl-like chains were synthesized. The characteristics of the me...Novel ordered mesoporous Eu(DBM)3phen/APTES-SBA-15 (EAS) composites with reasonable photoluminescence property and interesting morphology of bundles of pearl-like chains were synthesized. The characteristics of the mesostructure and the optical properties of the prepared samples were investigated by means of XRD, FTIR, SEM, TEM, N2 adsorption–desorption and PL spectroscopy. The results indicate that the as-made EAS composites have long-distance ordered mesoporous structure. Compared with the Eu(DBM)3phen complex, it is found that the EAS composites perform a considerable photoluminescence with good color purity. It is proposed that the anchored amine from the APTES and quantum size effect of the Eu(DBM)3phen complex have great effect on the photoluminescence of the EAS composites.展开更多
文摘Time-resolved fluorescence spectra of europium methylbenzoates (MBA)with 1,10-phenanthroline(phen)have been measured at room temperature.For each of the europium chelates,where the ligand triple states lie above the ~5D_1 level of Eu^(3-),the spectra providc evidence that the Eu^(3-) ~5D_0 state is populated by nonradiative energy transfer from the higher-lying ~5D_1,state.The relaxation time for energy decay from ~5D_1 state is measured in the microcrystals to bc of the order of a few microseconds.It is suggested that the ligand C=0 and C=C stretching vibrations and Eu-O vibrations,chclate ring and benzene ring vibrations make important contributions to the relaxation process.The ~5D\-1—~5D\-0 relaxation time of Eu- (p-MBA)_3phen is shorter than those of Eu(m-MBA)_3phen and Eu(o-MBA)_3phen since nonradiative degradation to ~5D_0 from ~5D_1 appears to be more strongly influenced by the E_u^(3+)sites in the former.
基金Project (SYSJJ2003-15) supported by the Opening Foundation of the Key Laboratory of the Ministry of Education of China
文摘Novel ordered mesoporous Eu(DBM)3phen/APTES-SBA-15 (EAS) composites with reasonable photoluminescence property and interesting morphology of bundles of pearl-like chains were synthesized. The characteristics of the mesostructure and the optical properties of the prepared samples were investigated by means of XRD, FTIR, SEM, TEM, N2 adsorption–desorption and PL spectroscopy. The results indicate that the as-made EAS composites have long-distance ordered mesoporous structure. Compared with the Eu(DBM)3phen complex, it is found that the EAS composites perform a considerable photoluminescence with good color purity. It is proposed that the anchored amine from the APTES and quantum size effect of the Eu(DBM)3phen complex have great effect on the photoluminescence of the EAS composites.
