In the preparation of this precursor tetraethlortho silicate (TEOS), sodium tungstate, ethyl alcohol, HCl and RECl3(RE=Eu,Tb) were mixed and then heated at 800 ℃ for 2 h, leading to a luminescent compound. The struct...In the preparation of this precursor tetraethlortho silicate (TEOS), sodium tungstate, ethyl alcohol, HCl and RECl3(RE=Eu,Tb) were mixed and then heated at 800 ℃ for 2 h, leading to a luminescent compound. The structure of the materials was characterized by TG-DTA and IR analysis, and the results indicate that the materials were in SiO2 network structure. Three-dimensional fluorescence spectra was used to characterize the luminescent properties of the materials. The luminescence property of doped and un-doped Eu3+or Tb3+ and Na2WO4 in silica materials were prepared and measured. The results show that good energy transfer from WO2-4 to Eu3+ ion, sensitized the luminescence intensity of Eu3+ remarkably. Tb3+ ion incorporated silica materials expressed the inverse energy transition from Tb3+ to WO2-4, however, we got the materials with homogeneous green blue fluorescent light. Finally, the energy transfer of WO2-4 and Eu3+, WO2-4 and Tb3+ were explained by energy levels diagram.展开更多
Fluorescence properties of Eu 3+ :Y 2SiO 5 have been investigated. Transitions between 5D and 7Fwere were studied with transmission spectra, fluorescence spectra, photoluminescence excitation ( or a...Fluorescence properties of Eu 3+ :Y 2SiO 5 have been investigated. Transitions between 5D and 7Fwere were studied with transmission spectra, fluorescence spectra, photoluminescence excitation ( or absorption ) spectra and site selective fluorescence spectra. The X ray powder diffraction pattern of Eu 3+ :Y 2SiO 5 shows that the crystal belong to monoclinic, and lattice's constants a, b, c and β are obtained by a simulation with the measured diffraction angles.展开更多
Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of...Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.展开更多
An acrylic monomer bearing carbazole moiety,3 methacrylamido 9 ethylcarbazole (MAECz)was synthesized and polymerized radically.Fluorescence studies showed that at the same chromophore concentration,the fluorescence in...An acrylic monomer bearing carbazole moiety,3 methacrylamido 9 ethylcarbazole (MAECz)was synthesized and polymerized radically.Fluorescence studies showed that at the same chromophore concentration,the fluorescence intensity of the polymer (P(MAECz) was much stronger than that of the monomer.This can be explained by what we termed fluorescence “Structural Self Quenching Effect”(SSQE).The stern volmer constants of P(MAECz) in solution quenched by several electron deficient vinyl monomers were obtained.It was found that the quenching efficiency of the quenchers was relevant to the degree of the electron deficiency.Also,the photopolymerization of acrylonitrile (AN) initiated by MAECz was investigated kinetically and a tentative initiation mechanism was proposed.展开更多
基金Project supported by State Natural Science Foundation (20161001)Natural Science Foundation of Inner Mongolia Autonomous Region Science Commission (200508010206)
文摘In the preparation of this precursor tetraethlortho silicate (TEOS), sodium tungstate, ethyl alcohol, HCl and RECl3(RE=Eu,Tb) were mixed and then heated at 800 ℃ for 2 h, leading to a luminescent compound. The structure of the materials was characterized by TG-DTA and IR analysis, and the results indicate that the materials were in SiO2 network structure. Three-dimensional fluorescence spectra was used to characterize the luminescent properties of the materials. The luminescence property of doped and un-doped Eu3+or Tb3+ and Na2WO4 in silica materials were prepared and measured. The results show that good energy transfer from WO2-4 to Eu3+ ion, sensitized the luminescence intensity of Eu3+ remarkably. Tb3+ ion incorporated silica materials expressed the inverse energy transition from Tb3+ to WO2-4, however, we got the materials with homogeneous green blue fluorescent light. Finally, the energy transfer of WO2-4 and Eu3+, WO2-4 and Tb3+ were explained by energy levels diagram.
文摘Fluorescence properties of Eu 3+ :Y 2SiO 5 have been investigated. Transitions between 5D and 7Fwere were studied with transmission spectra, fluorescence spectra, photoluminescence excitation ( or absorption ) spectra and site selective fluorescence spectra. The X ray powder diffraction pattern of Eu 3+ :Y 2SiO 5 shows that the crystal belong to monoclinic, and lattice's constants a, b, c and β are obtained by a simulation with the measured diffraction angles.
文摘Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.
文摘An acrylic monomer bearing carbazole moiety,3 methacrylamido 9 ethylcarbazole (MAECz)was synthesized and polymerized radically.Fluorescence studies showed that at the same chromophore concentration,the fluorescence intensity of the polymer (P(MAECz) was much stronger than that of the monomer.This can be explained by what we termed fluorescence “Structural Self Quenching Effect”(SSQE).The stern volmer constants of P(MAECz) in solution quenched by several electron deficient vinyl monomers were obtained.It was found that the quenching efficiency of the quenchers was relevant to the degree of the electron deficiency.Also,the photopolymerization of acrylonitrile (AN) initiated by MAECz was investigated kinetically and a tentative initiation mechanism was proposed.
