952 resultados para Hybrid materials


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A new class of steroid dimers (bile acid derivatives) linked through ester functionalities were synthesized, which gelled various aromatic solvents. The organogels formed by the three dimeric ester molecules showed birefringent textures and fibrous nature by polarizing optical microscopy and scanning electron microscopy, respectively. A detailed rheological study was performed to estimate the mechanical strengths of two sets of organogels. In these systems, the storage modulus varied in the range of 0.8-3.5 X 10(4) at 1% w/v of the organogelators. The exponents of scaling of the storage modulus and yield stress of the two systems agreed well with those expected for viscoelastic soft colloidal gels with fibrillar flocs. The nanofibers in the organogel were utilized to engineer gold nanoparticles of different sizes and shapes and generate new gel-nanoparticle hybrid materials.

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Monomers of methacrylate with various pi -conjugated pendants were designed and prepared in our laboratory, The monomer with suitable end-group was successfully assembled with nano-scale inorganic particles to form an orderly-aligned structure that showed special optical properties, both absorption and emission band were much red-shifted compared with the monomer, A new type of organic/inorganic hybrid materials was obtained by in situ polymerization of the assembly, The hybrid materials could also show special optical properties as the assembly, This might open a new route to tune the emission color.

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The authors report on the fabrication of 980 nm InGaAs strained quantum well lasers with hybrid materials of InGaAsP as waveguide and AlGaAs as cladding grown by metal organic chemical vapour deposition. The InGaAs/InGaAsP/AlGaAs diode lasers (100 x 800 mu m) with broadened waveguide structure exhibit a threshold current of 180 mA, a slope efficiency of 1.0 W/A, and a high characteristic temperature coefficient (T-0) of 230 K.

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目前,国内外对于铕和铽等稀土配合物的可见区发光和应用都有大量研究,但对具有近红外发光(800-1700 nm)性能的稀土配合物的研究还处于起步阶段。由于稀土的近红外发光在光纤通讯、激光系统及诊断学等方面应用具有特殊的优点,越来越引起人们的兴趣和重视。 稀土近红外发光配合物的致命弱点是其光、热和化学稳定性较差,从而限制了其在很多领域的实际应用。而溶胶-凝胶材料和介孔材料具有良好的光、热和化学稳定性,能改善客体分子的结构环境和化学微环境,从而能有效提高客体分子的发光性能。因此,本论文将具有优良近红外发光性能的稀土配合物分别与上述两种基质复合,从实验和理论研究稀土近红外发光杂化材料的性能和应用价值,制备出具有良好稳定性的高效稀土近红外发光杂化材料,以期为光纤通讯、激光等领域提供潜在的候选材料。围绕这一宗旨,开展了如下工作: 通过原位技术分别得到了掺杂和嫁接[Ln(dbm)3phen]化合物(Ln = Er, Nd, Yb)的杂化凝胶材料,Ln-D-P gel和Xerogel-Ln。通过对其近红外发光性能的研究,表明材料中配体能很好的保护稀土离子,并将能量有效的传递给稀土离子。采用Judd-Ofelt理论对所得部分材料进行了光谱分析,基于实验数据和理论分析表明其具有潜在的光放大和激光应用价值。 选择了两种含全氟化烷基链的β-二酮配体Hhfth和Htfnb,通过功能化的phen-Si配体,将三元配合物[Ln(hfth)3phen] (Ln = Er, Nd, Yb, Sm)和[Pr(tfnb)3phen]成功共价嫁接到介孔MCM-41和SBA-15杂化材料中,得到的衍生材料Ln(hfth)3phen–MCM-41、Pr(tfnb)3phen–MCM-41和Ln(hfth)3phen–SBA-15、Pr(tfnb)3phen–SBA-15都保持了高度有序的介孔p6mm结构,并展现出稀土离子特征的近红外发射。所得稀土配合物功能化的材料的发射光谱能完全覆盖对光通讯极具应用价值的1300-1600nm区域。 通过对Er(dbm)3phen–M41(X, Y) (X = 1~14, Y = 3, 6, 12, 18, 24 h)材料系统的比较研究,选择了X = 12, Y = 6作为合成目标材料的优化参数,通过功能化的phen-Si配体将[Ln(dbm)3phen]配合物共价嫁接于有序介孔MCM-41和SBA-15中(Ln = Er, Nd, Yb),所得两类材料Ln(dbm)3phenM41和Ln(dbm)3phenS15都保持了很好的介孔有序性,并具有良好的近红外发光性能。通过对Ln(dbm)3phenM41和Ln(dbm)3phenS15两类材料发光行为的比较,以及两类材料中稀土离子的含量及孔结构的分析,推出以SBA-15为载体得到的材料在相对发光强度和荧光寿命上,均比以MCM-41为载体的材料有所提高。 通过对8-羟基喹啉配体进行改性,合成了具有双功能的配体Q-Si,继而合成了共价嫁接8-羟基喹啉衍生物的介孔杂化材料Q–SBA-15,其形貌均一,并具有高度有序的介孔p6mm结构。通过配体交换反应,得到了嫁接稀土喹啉配合物的具有近红外发光性能的介孔杂化材料LnQ3–SBA-15 (Ln = Er, Nd, Yb),其仍然保持高度有序的介孔结构,且外形呈现与母体材料Q–SBA-15相似的弯曲圆柱状。激发配体的吸收,LnQ3–SBA-15材料都分别展现出相应稀土离子特征的近红外发射,并详细分析和讨论了所得介孔杂化材料的近红外发光性能。

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本文合成了几种多氟β-二酮配合物,并将其引入无机/有机杂化基质及中孔分子筛材料中,从而制备了发光性能良好的杂化材料。选用新型的多氟β-二酮作为有机配体,合成了几种衫、试配合物,通过IR、1H NMR等手段证实了配合物的生成,并研究了其发光性质。首次得到了以4,4,5,5,6,6,6-七氟-1-2-噻吩基)-1-已二酮(HTH)为配体的衫的配合物单晶(Sm(HT)3Phen),解析了其结构,结果表明其配位多面体为三角十二面体。将多氟三元配合物Tb(Tfacac)3phen通过溶胶一凝胶过程掺杂到γ-缩水甘油丙基醚三甲氧基硅烷(GPTMS)改性的有机/无机杂化基质中,制备了有机/无机杂化发光块状材料一及其薄膜材料;研究了稀土配合物在未改性基质和改性基质中的发光性质,以及不同基质对发光性能的影响,结果发现该杂化材料最大激发峰位相对于纯配合物发生了蓝移,且激发谱带变窄;考察了两种基质中配合物掺杂浓度对杂化材料的发光强度的影响,结果表明。稀土配合物在改性基质中比在未改性基质中掺杂浓度提高了。比较了粉末材料与相应薄膜的发光性能,发现薄膜材料巴的发光强度和荧光寿命有所降低,表明材料的不同状态对其发光性能有一定的影响。制备了中孔分子筛MCM-41及GPTMS、TMSPMC改性的有机/无机杂化中孔材料。回时成功地将稀土配合物Sm(HTH)3Phen、Tb(Tfacac)3Phen组装到MCM-41及两种改性的MCM-41中,合成了担载新型稀土有机配合物的无机-有机杂化中孔发光材料。通过对稀土配合物及其在分子筛中的荧光光谱分析,发现激发光谱发生了蓝移;而且不同的改性剂对不同的稀土配合物的影响不同。并制得了发光色纯度较高的稀土-TMSPMC-MCM-41复合发光体。

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The ligands 4,4,4-trifluoro-1-phenyl-1.3-butanedione (Hbfa) and 1,10-phenanthroline (phen) were used to prepare ternary lanthanide (Ln) complexes [Dy(bfa)(3)phen and Tm(bfa)(3)phen]. Crystal data: Dy(bfa)(3)phen C(42)H(26)FqN(2)O(6)Dy, triclinic, P (1) over bar, a= 9.9450(6) angstrom, b = 14.0944(9) angstrom, c = 14.6043(9) angstrom, alpha = 82.104(1)degrees, beta = 87.006(1)degrees, gamma = 76.490(1)degrees, V = 1971.1(2)angstrom(3), Z = 2; Tm(bfa)(3)phen C42H26F9N2O6Tm, triclinic, P (1) over bar, a = 9.898(5)angstrom, b = 13.918(5)angstrom, c = 14.753(5)angstrom, a = 83.517(5)degrees, alpha = 86.899(5)degrees, gamma = 76.818(5)degrees, V = 1965.3(14)angstrom(3), Z = 2. The coordination number of the central Ln(3+) (Ln = Dy, Tm) ion is eight, with six oxygen atoms from three Hbfa ligands and two nitrogen atoms from the phen ligand.

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A novel mesoporous material covalently bonded with 8-hydroxyquinoline (HQ) was synthesized (designated as Q-SBA-15). The 5-formyl-8-hydroxyquinoline grafted to.(3-aminopropyl)triethoxysilane, that is, alkoxysilane modified 8-hydroxyquinoline (Q-Si), was used as one of the precursors for the preparation of the Q-SBA-15 material. On the basis of the other function of the Q-Si of coordinating to lanthanide (Ln) ions, for the first time, the LnQ(3) complexes (Ln = Er, Nd, Yb) have been covalently bonded to the SBA-15 materials.

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Multiwalled carbon nanotube (MWCNT)/ionic liquid/gold nanoparticle hybrid materials have been prepared by a chemical route that involves functionalization of MWCNT with amine-terminated ionic liquids followed by deposition of Au. Transmission electron microscopy revealed well-distributed Au with a narrow size distribution centered around 3.3 nm. The identity of the hybrid material was confirmed through Raman and X-ray photoelectron spectroscopy.

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A near-infrared luminescent macroporous material (PL-Macromaterial) and a near-infrared luminescent/magnetic bifunctional macroporous material (MML-Macromaterial) were synthesized by using polystyrene microspheres (PS) and Fe3O4 @polystyrene core-shell nanoparticles (Fe3O4@PS), respectively, as templates. Both the PL-Macromaterial and the M/PL-Macromaterial show the characteristic emission of the Er 3, ion. Moreover, the M/PL-Macromaterial possesses superparamagnetic properties at room temperature.

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Ternary europium complex Eu(tta)(3)phen was covalently bonded with the general mesoporous. material SBA-15 and SBA-15-type of periodic mesoporous organosilica (PMO) material via impregnation of Eu(tta)(3)center dot 2H(2)O into phen-S15 and phen-PMO, respectively, through a ligand exchange reaction. The parent materials of phen-S15 and phen-PMO were synthesized by co-condensation of tetraethylorthosilicate (TEOS) or 1,2-bis(triethoxysilyl)ethane (BTESE) and the functionalized chelate ligand 5-(N,N-bis(3-triethoxysilyl)propyl)ureyl-1,10-phenanthroline (phen-Si) in the presence of Pluronic P123 surfactant as template, which were confirmed by SEM, XRD, FTIR, Si-29 CP-MAS NMR, and N-2 adsorption measurements.

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The crystal structure of a ternary Tm(DBM)(3)phen complex (DBM - dibenzoylmethane; phen = 1. 10-phenanthroline) and the synthesis of hybrid mesoporous material in which the complex covalently bonded to mesoporous MCM-41 are reported. Crystal data: Tm(DBM)(3)phen C59H47N2O7Tm, monoclinic P21/c, a = 19.3216(12) A, b = 10.6691(7) A, c = 23.0165(15)A, alpha = 90, beta = 91.6330(10), gamma = 90, V = 4742.8(5) A(3), Z = 4. The properties of the Tm(DBM)(3)phen complex and the corresponding hybrid mesoporous material [Tm(DBM)(3)phen-MCM-41] have been studied. The results reveal that the Tm(DBM)(3)phen complex is successfully covalently bonded to MCM-41.