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A series of tetranuclear coordination clusters [Ln4L2(HL)2(μ3-OH)2(NO3)2](NO3)2 [Ln = Dy (1·3CH3CN·5H2O), Gd (2·4CH3CN·5H2O), H2L = 6,6′-dimethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis-(nitrilomethylidyne)] diphenol] and dinuclear complexes [LnZnL(NO3)3(H2O)]·2CH3CN [Ln = Dy (3), Er (4), Yb (5), Lu (6)] were prepared and characterized. Static magnetic measurements revealed the presence of ferromagnetic interactions between the Dy(III) ions and weak antiferromagnetic couplings between the Gd(III) ions in 1 and 2. Dynamic magnetic studies showed that complexes 1 and 3 exhibit slow magnetic relaxation under a zero static field as expected for single molecule magnet (SMM) behavior, whereas complex 4 is a field-induced SMM. Clear hysteresis loops were observed for 1 and 3 at 2 K, verifying their SMM behavior. Luminescence investigations demonstrated that complexes 1 and 2 show ligand-based emission and can act as luminescence thermometers below 100 K, whereas complexes 3 and 5 display the characteristic emission of lanthanide ions. From the high-resolution emission spectra of 3 and 5, the energy gaps between the ground state and excited states of Dy(III) and Yb(III) ions were determined. [ABSTRACT FROM AUTHOR]

In this study, a kind of much uniform and rule hemispheric ordered porous Eu (TTA) 3 (TPPO) 2 /ZnO composite was synthesized by liquid phase grafting method, and ordered mesoporous ZnO was necessarily used as precursor during preparation process. The diameter of the hemispheric particle was about 1 μm, and the surfaces of the hemispheric particles were distributed a lot of ordered porous, the pore size was about 2.18 nm. Eu(TTA) 3 (TPPO) 2 was assembled into porous ZnO matrix by liquid phase grafting method. At the same time, the Eu(TTA) 3 (TPPO) 2 guest material played a role of structure-directing agent, which led to a realignment of porous ZnO particle, and a hemispheric morphology was obtained. ZnO had a strong emission peak at 469 nm which overlaps with the 7F 0 –5D 2 transition excitation peak of Eu3+ at 465 nm, it indicated that the effective energy transfer could be happened between ZnO and Eu3+, which strongly enhanced the luminescence intensity of Eu3+. The optimal ratios of Eu3+ was also discussed. Unlabelled Image • Uniform and rule hemispheric Eu(TTA) 3 (TPPO) 2 /ZnO composite was synthesized. • The surfaces of the material were distributed with ordered mesoporous. • Eu(TTA) 3 (TPPO) 2 structure-directing agent led to obtain hemispheric morphology. • ZnO Emission overlapped with Eu3+ excitation, it enhanced Eu3+ luminescence. [ABSTRACT FROM AUTHOR]

In this study, different techniques were used to synthesize the Eu 2 O 3 –ZnO/(SBA-15) composite materials in high temperature, and the luminescent characteristics of prepared materials were studied. The results showed that the frameworks of the prepared materials were kept intact, and their structures were kept highly ordered. The prepared Eu 2 O 3 –ZnO/(SBA-15) materials showed luminescent characteristics. Li + ions doped in ZnO act as the charge compensation and the luminescence sensitizing agent. They enabled the prepared composite materials to show a stronger luminescent phenomenon. The guest materials were distributed in the pores of SBA-15, which shielded them from the external environment. The Eu 2 O 3 –ZnO/(SBA-15) composites exhibited high relative luminescent intensity. [ABSTRACT FROM AUTHOR]

• The Tb3+ and Eu3+ phosphates were directly assembled into the pores of mesoporous SiO 2 aerogel matrix by sol-gel method. • The prepared material showed gel block structure whose surfaces were distributed a large number of disordered mesoporous. • The prepared material had a stronger emission of Eu3+ at 594 nm, but the past reports at 612 nm. • The optimal proportion of Tb3+ and Eu3+ was confirmed according to the strongest emission. In this study, the Tb3+ and Eu3+ phosphates were directly assembled into the pores of mesoporous SiO 2 aerogel matrix by sol-gel method, and (Eu3+-Tb3+) PO 4 /SiO 2 composite was obtained. The prepared material showed gel block structure whose surfaces were distributed a large number of disordered mesoporous. The advantage of the method was that the rare earth elements could be absolutely assembled into the pores of the SiO 2 aerogel, which resolved a bottleneck problem of the guest materials assembly quantity and guest materials location in porous host materials. The study provided an effective method for host-guest material preparation. The luminescent characters of the (Eu3+-Tb3+) PO 4 /SiO 2 composite were studied, the prepared material showed a stronger emission of Eu3+ at 594 nm which was distinct with the past reports at 612 nm. The optimal proportion of Tb3+ and Eu3+ was confirmed according to the sample with the strongest emission. [ABSTRACT FROM AUTHOR]

Abstract A kind of chrysanthemum-like ordered mesoporous Eu3+/ZnO luminescent material was synthesized by a hydrothermal method. In prepared process, an ordered mesoporous zinc oxide (OMZ) precursor must be synthesized which was prepared by soft template method, and the sulfosalicylic acid must be used as organic ligands. The prepared Eu3+/ZnO composite showed a unique chrysanthemum-like morphology whose surfaces were distributed the ordered mesoporous, the average diameter of the chrysanthemum-like particles was about 10 μm, the average width of the petals was about 100 nm, and the average length of the petals was about 3 μm. A strongest emission peak was located at 590 nm when the 394 nm was used as excitation wavelength. A strongest emission peak was located at 417 nm when the 359 nm was used as excitation wavelength. The influences of the Eu3+ concentration, hydrothermal temperature and hydrothermal time were studied, and the relevant parameters were confirmed according to the strongest emissions. [ABSTRACT FROM AUTHOR]

In this study, the sulfosalicylic acid (SSA)-Tb and Yb compound were systematically assembled into the pores of SBA-15 by hydrothermal method. The luminescence properties of the prepared materials were studied through luminescence spectra. The influences of the content of Yb 3+ and Tb 3+ on luminescent properties have been studied, and the luminescence mechanisms were analyzed. By the emission spectrum intensity, the optimum proportion of Tb and Yb was confirmed. In prepared materials, the ordered mesoporous structures were retained, and the prepared materials showed the much stronger emission of Tb 3+ at 543 nm. The luminescence intensity attained the maximum when Yb 3+ molar content was 4%, and the Tb 3+ molar content was 2%. The prepared materials have potential applications value in luminescent materials field. [ABSTRACT FROM AUTHOR]

In this study, the terbium phosphate and ytterbium oxide were successfully introduced into SBA-15 by high temperature solid phase method, and got TbPO 4 -Yb 2 O 3 /SBA-15 composite materials. The luminescence properties of the prepared materials were studied by luminescence spectroscopy. The influences of Yb 2 O 3 to Tb 3+ luminescent properties have been studied, and the mechanism was analysed. The influences the concentration of Tb 3+ on luminescent intensity have been studied. The luminescent quenching mechanism was also analyzed. By the emission spectrum intensity, the optimum proportion of Tb and Yb was confirmed. [ABSTRACT FROM AUTHOR]

For the first time, the order mesoporous zinc oxide was synthesized by a soft template synthesis method. The Eu and La phosphate were introduced into the prepared mesoporous zinc oxide by the high temperature solid phase method, and got the mesoporous rare earth/zinc oxide composite materials. The luminescence characters of the materials were studied. The influences of La to Eu luminescent properties had been studied, and the optimum proportion of Eu and La was discussed. The influences of La and Eu to ZnO luminescence properties were also been studied. La phosphate had the large influence to Eu luminescent. ZnO had a strong emission peak at 469 nm, which overlapped with the 7 F 0 – 5 D 2 transition excitation peak of Eu at 465 nm. It indicated that the effective energy transfer happened between ZnO and Eu, which strongly enhanced the luminescence intensity of Eu. At the same time, the Eu and La phosphates could regulate the defect density of ZnO, which could regulate the luminescent intensity of ZnO, and realized the adjustment of luminescent color between green and red light. [ABSTRACT FROM AUTHOR]

Abstract: A new orange–red phosphor Sr3P4O13: Eu was synthesized by a high temperature solid-state reaction. X-ray powder diffraction (XRD) analysis confirms the formation of Sr3P4O13 in a triclinic system with space group . The photoluminescence spectra indicate that Sr3P4O13: Eu can be excited effectively by near ultraviolet (NUV) light and exhibit bright orange–red emission with excellent color stability. Interestingly, the emission bands of Eu2+ and Eu3+ were both observed in the photoluminescence spectra of air-sintered Sr3P4O13: Eu phosphor due to the self-reduction effect. This kind of abnormal reduction was explained by a charge compensation model. [Copyright &y& Elsevier]

The porous Eu(TTA) 3 (TPPO) 2 /SnO 2 (ETTS, TTA: 2-thenoyltrifluoroacetonate and TPPO: triphenylphosphine oxide) composite was prepared via sol-gel method with tetraethyl orthosilicate (TEOS) as catalyst which showed the cumulate litchi shell-like structure. The Eu(TTA) 3 (TPPO) 2 organic complexes (ETT) could be absolutely distributed into the pores of the SnO 2 matrix at the molecular level through sol-gel process. SiO 2 was used as the hard template which was removed to increase porosity during the prepared process. The red emission of ETTS was exhibited under the 368 nm excitation light, and much better luminescence properties was shown after washing off SiO 2 (ETTS-W) which was about 4 times of unwashed ETTS (ETTS-UW) and 15.6 times of ETT for 615 nm emission when Eu content was 6 wt%. The excellent luminescence property of ETTS-W samples was mainly attributed to the organic ligands, the pore structure after removing SiO 2 and stronger ultraviolet absorption capacity of SnO 2 matrix. Image 1 • Porous Eu(TTA) 3 (TPPO) 2 /SnO 2 was fabricated by sol-gel method with TEOS as catalyst. • Eu(TTA) 3 (TPPO) 2 /SnO 2 showed the cumulate litchi shell-like structure. • The study provides a technique for the enhancing of the luminescent intensity. • Emission intensity of Eu(TTA) 3 (TPPO) 2 /SnO 2 was enhanced by the removal of silica. [ABSTRACT FROM AUTHOR]

A novel-far red emission Li 6 CaLa 2 Sb 2 O 12 (LCLSO):Mn4+ phosphor was prepared by traditional high temperature solid state reaction method. The morphology, spectral characteristics and luminescence properties of the phosphors were all studied systematically. Based on the results, when x = 0.0045 (x represents the doping concentration of Mn4+), the emission intensity of LCLSO: x Mn4+ phosphor reaches the maximum, and the concentration quenching occurs after the Mn4+ doping concentration exceeds 0.0045. In addition, the effect of Al3+-doped on the luminescent properties of the materials was also studied. The optimum doping concentration of Al3+ is y = 0.009 (y represents the doping concentration of Al3+), and the luminescence intensity of Mn4+ can be increased about 4 times. Moreover, the integrated luminescence intensity, the thermal activation energy, and decay time can be obtained via calculation. In summary, LCLSO:Mn4+, Al3+ phosphor exhibits good luminescence efficiency and thermal stability, and possesses the latent application foreground in plant growth lighting. • Li 6 CaLa 2 Sb 2 O 12 :Mn4+ far-red phosphors were prepared by high temperature method. • Al3+-doped can lead to better luminescent properties of the LCLSO:Mn4+ phosphor. • The emission of LCLSO:Mn4+,Al3+ matches well with the absorption spectrum of P FR. [ABSTRACT FROM AUTHOR]