yb3＋/Dy3＋ co-doped A1203 nanopowders have been prepared by the non-aqueous sol-gel method and their up- conversion photoluminescence spectra are measured under excitation by a 980-nm semiconductor laser. The results...yb3＋/Dy3＋ co-doped A1203 nanopowders have been prepared by the non-aqueous sol-gel method and their up- conversion photoluminescence spectra are measured under excitation by a 980-nm semiconductor laser. The results show that there are comparatively abundant spectra of up-conversion emissions centered at 378, 408, 527 and 543, and 663 nm, corresponding to 4C9/2→ 6H13/2, 4C9/2→ 6Hll/2, 4115/2 → 6H13/2, and 4F9/2 →6Hll/2 transitions of Dy3＋, respectively. Two-photon and three-photon processes are involved in ultraviolet, violet, green, and red up-conversion emissions. The energy transition between Yb3＋ and Dy3＋ is discussed.展开更多
The long afterglow fluorescent material of M1-3xAl2O4:Eu2+ x/Dy3+2x(M2+= Sr2+, Ca2+ and Ba2+) phosphors are successfully synthesized by calcining precursor obtained via co-precipitation method at 1300oC for 4 h with r...The long afterglow fluorescent material of M1-3xAl2O4:Eu2+ x/Dy3+2x(M2+= Sr2+, Ca2+ and Ba2+) phosphors are successfully synthesized by calcining precursor obtained via co-precipitation method at 1300oC for 4 h with reducing atmosphere (20% H2 and 80% N2). The phase evolution, morphology and afterglow fluorescent properties are systematically studied by the various instruments of XRD, FE-SEM, PLE/PL spectroscopy and fluorescence decay analysis. The PL spectra shows that the Sr1-3xAl2O4:Eu2+x/Dy3+ 2x phosphors display vivid green emission at s519 nm (4f65d1!4f7 transition of Eu2+) with monitoring of the maximum excitation wavelength at s334 nm (8S7=2!6IJ transition of Eu2+), among which the optimal concentration of Eu2+ and Dy3+ is 15 at.% and 30 at.%, respectively. The color coordinates and temperature of Sr1-3xAl2O4:Eu2+ x/Dy3+ 2x phosphors are approximately at (s0.27, s0.57) and s6700 K, respectively. On the above basis, the M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors is obtained by the same method. The PL spectra of these phosphors shows the strongest blue emission at s440 nm and cyan emission at s499 nm under s334 nm wavelength excitation, respectively, which are blue shifted comparing to Sr1??3xAl2O4:Eu2+ x/Dy3+ 2x phosphors. The color coordinates and temperatures of M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors are approximately at (s0.18, s0.09), s2000 K and (s0.18, s0.42), s11600 K, respectively. In this work, long afterglow materials of green, blue and cyan aluminates phosphors with excellent properties have been prepared, in order to obtain wide application in the field of night automatic lighting and display.展开更多
An organic-inorganic composite dip-coating method was adopted in order to obtain ideal water repellent cotton fabrics. To be specific, a dual-functional coating with both superhydrophobic and luminescent properties wa...An organic-inorganic composite dip-coating method was adopted in order to obtain ideal water repellent cotton fabrics. To be specific, a dual-functional coating with both superhydrophobic and luminescent properties was prepared on cotton fabric by using a dip-coating solution comprising （3-aminopropyl） trimethoxysilane （APTMS） modified SrA1204：Eu2＋,Dy3＋particles, SU8, and fluorinated alkyl silane （FAS）. The micro/nano-scale roughness generated by SrA1204：Eu2＋,Dy3＋ particles, together with low-sur- face-energy FAS, rendered the cotton fabric superhydrophobic with a water contact angle of about 160° and a sliding angle as small as 2°. The coated fabric could withstand at least 100 cycles of standard laundry. The emission spectra of the coated fabric showed two emission peaks at 440 and 520 nm, which belonged to the blue and yellow-green color areas, respectively. The afterglow duration of the coated fabric was mainly influenced by the different depths of the trap levels in the SrA1204：Eu2＋,Dy3＋.展开更多
A series of Eu3＋ and Dy3＋ doped/co-doped as well as un-doped BaB2Si2Os phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3＋ and red emission fro...A series of Eu3＋ and Dy3＋ doped/co-doped as well as un-doped BaB2Si2Os phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3＋ and red emission from Eu3＋. The f-f transitions in- volving the lanthanide ions along with dopant site occupancy were discussed thoroughly. Phonon assisted energy transfer process was observed from Eu3＋ to Dy3＋, which enhanced the emissions of Dy3＋. Combinations of the emissions from Eu3＋ and Dy3＋ showed a possible white to red tuneable emission on the CIE diagram. The white warmth emissions of the phosphor were revealed to be ad- justable through designing the dopant concentration and excitation wavelengths. An unusual energy transfer that originated from Eu3＋ to Dy3＋ was also discovered and the energy transfer mechanism was discussed. Proposed energy transfer mechanism was investigated using luminescence decay lifetime. All the phosphor exhibited efficient excitation in the UV range which matched well with the emissions from GaN-based LED chips. This presented the BaB2Si208 phosphor as a promising candidate for white LED applications. The effects of doping on the structural properties and the optical band gap of BaB2Si208 phosphor were also discussed in this study.展开更多
In recent years there has been growing interest in lanthanide-based multifunctional materials that exhibit interesting photophysical properties.This work presents spectroscopic and crystallographic characterization of...In recent years there has been growing interest in lanthanide-based multifunctional materials that exhibit interesting photophysical properties.This work presents spectroscopic and crystallographic characterization of a new dysprosium complex with sulfonylamidophosphate ligand.The crystal structure of[NaDy(SP)4]2·i-PrOH was determined and refined.It turns out that the Dy(Ⅲ)complex is not isostructural with earlier reported compounds and crystallizes in the monoclinic system(space group P21).Two crystallographically independent dysprosium atoms are in eight-fold coordination,with a triangular dodecahedron geometry.Absorption,emission(77 and 300 K)and excitation spectra as well as fluorescence decay time measurements allowed optical characterization of obtained complex.Efficient energy transfer from SP-ligand to Dy^3+ion has been demonstrated.The Judd-Ofelt theory was applied to predict fundamental fluorescence properties of Dy^3+ion in the title chelate.The Judd-Ofelt intensity parameters were used to determine the emission transition probabilities,fluorescence branching ratios and radiative lifetime of the emitting 4F9/2 level.The obtained results indicate that the investigated chelate can be a potential candidate for OLEDs emitting yellow light.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No. 11004092） and the Scientific Research Fund of Education Department of Liaoning Province, China （Grant No. 2009A417）.
文摘yb3＋/Dy3＋ co-doped A1203 nanopowders have been prepared by the non-aqueous sol-gel method and their up- conversion photoluminescence spectra are measured under excitation by a 980-nm semiconductor laser. The results show that there are comparatively abundant spectra of up-conversion emissions centered at 378, 408, 527 and 543, and 663 nm, corresponding to 4C9/2→ 6H13/2, 4C9/2→ 6Hll/2, 4115/2 → 6H13/2, and 4F9/2 →6Hll/2 transitions of Dy3＋, respectively. Two-photon and three-photon processes are involved in ultraviolet, violet, green, and red up-conversion emissions. The energy transition between Yb3＋ and Dy3＋ is discussed.
基金the National Natural Science Foundation of China (No. 51602126)the National Key Research and Development Plan of China (No. 2016YFB0303505)+1 种基金China and University of Jinan Postdoctoral Science Foundation (No. 2017M622118 and XBH1716)the 111 Project of International Corporation on Advanced Cement-based Materials (D17001).
文摘The long afterglow fluorescent material of M1-3xAl2O4:Eu2+ x/Dy3+2x(M2+= Sr2+, Ca2+ and Ba2+) phosphors are successfully synthesized by calcining precursor obtained via co-precipitation method at 1300oC for 4 h with reducing atmosphere (20% H2 and 80% N2). The phase evolution, morphology and afterglow fluorescent properties are systematically studied by the various instruments of XRD, FE-SEM, PLE/PL spectroscopy and fluorescence decay analysis. The PL spectra shows that the Sr1-3xAl2O4:Eu2+x/Dy3+ 2x phosphors display vivid green emission at s519 nm (4f65d1!4f7 transition of Eu2+) with monitoring of the maximum excitation wavelength at s334 nm (8S7=2!6IJ transition of Eu2+), among which the optimal concentration of Eu2+ and Dy3+ is 15 at.% and 30 at.%, respectively. The color coordinates and temperature of Sr1-3xAl2O4:Eu2+ x/Dy3+ 2x phosphors are approximately at (s0.27, s0.57) and s6700 K, respectively. On the above basis, the M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors is obtained by the same method. The PL spectra of these phosphors shows the strongest blue emission at s440 nm and cyan emission at s499 nm under s334 nm wavelength excitation, respectively, which are blue shifted comparing to Sr1??3xAl2O4:Eu2+ x/Dy3+ 2x phosphors. The color coordinates and temperatures of M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors are approximately at (s0.18, s0.09), s2000 K and (s0.18, s0.42), s11600 K, respectively. In this work, long afterglow materials of green, blue and cyan aluminates phosphors with excellent properties have been prepared, in order to obtain wide application in the field of night automatic lighting and display.
基金Project supported by the Fundamental Research Funds for the Central Universities(Key Projects of Scientific Research Plan,No.JUSRP51505)
文摘An organic-inorganic composite dip-coating method was adopted in order to obtain ideal water repellent cotton fabrics. To be specific, a dual-functional coating with both superhydrophobic and luminescent properties was prepared on cotton fabric by using a dip-coating solution comprising （3-aminopropyl） trimethoxysilane （APTMS） modified SrA1204：Eu2＋,Dy3＋particles, SU8, and fluorinated alkyl silane （FAS）. The micro/nano-scale roughness generated by SrA1204：Eu2＋,Dy3＋ particles, together with low-sur- face-energy FAS, rendered the cotton fabric superhydrophobic with a water contact angle of about 160° and a sliding angle as small as 2°. The coated fabric could withstand at least 100 cycles of standard laundry. The emission spectra of the coated fabric showed two emission peaks at 440 and 520 nm, which belonged to the blue and yellow-green color areas, respectively. The afterglow duration of the coated fabric was mainly influenced by the different depths of the trap levels in the SrA1204：Eu2＋,Dy3＋.
基金supported by Fundamental Research Grant Scheme of Malaysia(J130000.2526.03H97)the National Natural Science Foundation of China(51372142)
文摘A series of Eu3＋ and Dy3＋ doped/co-doped as well as un-doped BaB2Si2Os phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3＋ and red emission from Eu3＋. The f-f transitions in- volving the lanthanide ions along with dopant site occupancy were discussed thoroughly. Phonon assisted energy transfer process was observed from Eu3＋ to Dy3＋, which enhanced the emissions of Dy3＋. Combinations of the emissions from Eu3＋ and Dy3＋ showed a possible white to red tuneable emission on the CIE diagram. The white warmth emissions of the phosphor were revealed to be ad- justable through designing the dopant concentration and excitation wavelengths. An unusual energy transfer that originated from Eu3＋ to Dy3＋ was also discovered and the energy transfer mechanism was discussed. Proposed energy transfer mechanism was investigated using luminescence decay lifetime. All the phosphor exhibited efficient excitation in the UV range which matched well with the emissions from GaN-based LED chips. This presented the BaB2Si208 phosphor as a promising candidate for white LED applications. The effects of doping on the structural properties and the optical band gap of BaB2Si208 phosphor were also discussed in this study.
文摘In recent years there has been growing interest in lanthanide-based multifunctional materials that exhibit interesting photophysical properties.This work presents spectroscopic and crystallographic characterization of a new dysprosium complex with sulfonylamidophosphate ligand.The crystal structure of[NaDy(SP)4]2·i-PrOH was determined and refined.It turns out that the Dy(Ⅲ)complex is not isostructural with earlier reported compounds and crystallizes in the monoclinic system(space group P21).Two crystallographically independent dysprosium atoms are in eight-fold coordination,with a triangular dodecahedron geometry.Absorption,emission(77 and 300 K)and excitation spectra as well as fluorescence decay time measurements allowed optical characterization of obtained complex.Efficient energy transfer from SP-ligand to Dy^3+ion has been demonstrated.The Judd-Ofelt theory was applied to predict fundamental fluorescence properties of Dy^3+ion in the title chelate.The Judd-Ofelt intensity parameters were used to determine the emission transition probabilities,fluorescence branching ratios and radiative lifetime of the emitting 4F9/2 level.The obtained results indicate that the investigated chelate can be a potential candidate for OLEDs emitting yellow light.
