942 resultados para Organic-inorganic nanocomposites
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A study on mixed culture of mirror carp (Cyprinus carpio Lin.), tilapia (Oreochromis niloticus Lin.), silver carp (Hypophthalmicthys molitrix Val.) and Thai sharpunti (Puntius gonionotus Bleeker) in the ratio of 1:2:2:5 was conducted in 12 seasonal mini ponds (30 m² each) for 105 days. There were six treatments each with two replicates and each pond was stocked with a total of 100 fishes. Rice bran and mustard oil cake were used as supplemental feed either in combination or alone in presence or absence of fertilizer. Fertilizers were used in the form of organic, inorganic or both. The best growth performance of mirror carp, tilapia and Thai sharpunti was obtained in treatment III which received both fertilizer (organic+inorganic) and rice bran while the highest growth of silver carp was obtained in treatment VI receiving only inorganic fertilizer. However, the overall best production (2450 Kg/ha) and economic return for the culture period was obtained in treatment VI followed by treatment III. The results are discussed in the light of water quality parameters.
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We propose an all-laser processing approach allowing controlled growth of organic-inorganic superlattice structures of rare-earth ion doped tellurium-oxide-based glass and optically transparent polydimethyl siloxane (PDMS) polymer; the purpose of which is to illustrate the structural and thermal compatibility of chemically dissimilar materials at the nanometer scale. Superlattice films with interlayer thicknesses as low as 2 nm were grown using pulsed laser deposition (PLD) at low temperatures (100 °C). Planar waveguides were successfully patterned by femtosecond-laser micro-machining for light propagation and efficient Er(3+)-ion amplified spontaneous emission (ASE). The proposed approach to achieve polymer-glass integration will allow the fabrication of efficient and durable polymer optical amplifiers and lossless photonic devices. The all-laser processing approach, discussed further in this paper, permits the growth of films of a multitude of chemically complex and dissimilar materials for a range of optical, thermal, mechanical and biological functions, which otherwise are impossible to integrate via conventional materials processing techniques.
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Nacre is a technologically remarkable organic-inorganic composite biomaterial. It consists of an ordered multilayer structure of crystalline calcium carbonate platelets separated by porous organic layers. This microstructure exhibits both optical iridescence and mechanical toughness, which transcend those of its constituent components. Replication of nacre is essential for understanding this complex biomineral, and paves the way for tough coatings fabricated from cheap abundant materials. Fabricating a calcitic nacre imitation with biologically similar optical and mechanical properties will likely require following all steps taken in biogenic nacre synthesis. Here we present a route to artificial nacre that mimics the natural layer-by-layer approach to fabricate a hierarchical crystalline multilayer material. Its structure-function relationship was confirmed by nacre-like mechanical properties and striking optical iridescence. Our biomimetic route uses the interplay of polymer-mediated mineral growth, combined with layer-by-layer deposition of porous organic films. This is the first successful attempt to replicate nacre, using CaCO(3).
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Covering a nano-patterned titanium dioxide photonic crystal (PC) within a well-oriented film of dye-doped liquid crystal (LC), a distributed feedback laser is constructed whereby the emission characteristics can be manipulated in-situ using an electric field. This hybrid organic-inorganic structure permits simultaneous selectivity of both the beam pattern and laser wavelength by electrical addressing of the LC director. In addition, laser emission is obtained both in the plane and normal to the PC. Along with experimental data, a theoretical model is presented that is based upon an approximate calculation of the band structure of this birefringent, tuneable laser device. © 2013 AIP Publishing LLC.
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Hybrid bulk heterojunction solar cells based on blend of poly(3-hexylthiophene) (P3HT) and TiO2 nanotubes or dye(N719) modified TiO2 nanotubes were processed from solution and characterized to research the nature of organic/inorganic hybrid materials. Compared with the pristine polymer P3HT and TiO2 nanoparticles/P3HT solar cells, the TiO2 nanotubes/P3HT hybrid solar cells show obvious performance improvement, due to the formation of the bulk heterojunction and charge transport improvement. A further improvement in the device performance can be achieved by modifying TiO2 nanotube surface with a standard dye N719 which can play a role in the improvement of both the light absorption and charge dissociation. Compared with the non-modified TiO2 nanotubes solar cells, the modified ones have better power conversion efficiency under 100 mW/cm(2) illumination with 500W Xenon lamp. (C) 2008 Elsevier B. V. All rights reserved.
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Tin disulfide (SnS2) nanocrystalline/amorphous blended phases were synthesized by mild chemical reaction. Both X-ray diffraction and transmission electron microscopy measurements demonstrate that the as-synthesized particles presented very small size, with a diameter of only a few nanometers. The photoluminescence (PL) spectrum suggests efficient splitting of photo-generated excitons in poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) and SnS2 hybrid films. Organic/inorganic hybrid solar cells comprising MDMO-PPV and SnS2 were prepared, giving photovoltage, photocurrent, fill factor and efficiency values of 0.702 V, 0.549 mA/cm(2), 0.385 and 0.148%, respectively, which suggests that this phase-blended inorganic semiconductor can also serve as a promising solar energy material. (C) 2009 Elsevier Ltd. All rights reserved.
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Poly(3,4-ethylenedioxythiopliene):poly(styrene sulfonate) (PEDOT:PSS) films have been electrochemically polymerized in situ on ITO glass substrate in boron trifluoride diethyl etherate electrolyte (BFEE). Cyclic voltammograms show good redox activity and stability of the PEDOT films. These films had been directly used to fabricate organic-inorganic hybrid solar cells with the structure of ITO/PEDOT/ZnO:MDMC-PPV/Al. The solar cells made of electrochemically polymerized films exhibit higher energy conversion efficiencies compared with that prepared by the spin-coating method, and the highest value is 0.33%. This in-situ electropolymerized method effectively simplifies fabricating procedures and may blaze a facile and economical route for producing high-efficiency solar cells.
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有机-无机钙钛矿型杂化半导体材料结合了有机和无机材料优点,并在分子水平上自组装形成复合材料,具有独特的光、电、磁等性质,在许多领域具有潜在的应用。基于第四主族金属卤化物的杂化钙钛矿是本论文研究的主题,这一类杂化钙钛矿材料是一类独特的半导体材料,其光功能引起人们越来越多的重视。 为此,本论文通过选择不同的有机阳离子配体制备了新型的基于卤化铅的有机-无机杂化钙钛矿结构单晶材料和薄膜,对它们的发光性质进行了研究。利用N-(3-胺基丙基)咪唑和溴化铅在氢溴酸溶液中反应得到了罕见的(110)取向杂化钙钛矿(C6H13N3)2PbBr4 (monoclinic, P21/c)。所得到的杂化钙钛矿在吸收(392 nm)及发射(424 nm)光谱中均存在激子的特征峰。同时,由于N-(3-胺基丙基)咪唑的光活性,得到的杂化材料具有独特的发光性质,在无机层与有机层之间发生了能量传递,使得有机配体的峰位发生红移并且发光强度明显增加。利用CASTEP (Cambridge Serial Total Energy Package) 总能计算软件包对配合物及配体的能带结构进行了计算。结果证明了配体在杂化材料中发光的红移及激子与配体间的能量传递。另外,还发现了一个有机配体2-(2-氨基乙基)硫脲也能够与金属卤化物络合形成(110)取向的有机-无机杂化钙钛矿结构C3H11SN3PbBr4(monoclinic P21/c),由于有机配体的不同,2-(2-氨基乙基)硫脲构筑的(110)取向杂化钙钛矿结构较N-(3-胺基丙基)咪唑构筑的(110)取向杂化钙钛矿结构有较大程度的扭曲变形,使得它们的发光性质有所不同。 邻-(胺基甲基)吡啶,间-(胺基甲基)吡啶,对-(胺基甲基)吡啶在相同条件下与溴化铅组装,得到0-D [(m-C6H10N2)2PbBr6] (orthorhombic, Pbca), 1-D [(o-C6H10N2)PbBr4] (monoclinic, P21/c), 2-D [p-(C6H10N2)PbBr4] (orthorhombic, Pbca) 等不同维数的溴化铅骨架。其中间-(胺基甲基)吡啶与溴化铅在酸性条件下形成稀有的0-D杂化钙钛矿;邻-(胺基甲基)吡啶在相同条件下形成2-D层状杂化钙钛矿;对-(胺基甲基)吡啶则得到共边八面体组成的一维链。证实了有机配体氢键和空间位阻对无机结构的形成起限制作用。得到的杂化钙钛矿化合物的无机层激子特征吸收峰分别位于428 nm(0-D)和431 nm(1-D),无机层激子特征发射峰位于461 nm (0-D)和467 nm(1-D)。 由于甲基咪盐的特殊胺盐构型,我们选用甲基咪盐取代的吡啶作为有机阳离子配体来构筑基于溴化铅的杂化钙钛矿,分别为3-甲咪基吡啶和4-甲咪基吡啶。3-甲咪基吡啶与溴化铅在酸性条件下构筑未见文献报道的即共点又共边的Pb-Br八面体连成无机层网络的杂化结构(C6H13N3)PbBr4 (monoclinic, C2/c)。4-甲咪基吡啶与溴化铅在相同条件下构筑的是常见的(100)取向的杂化钙钛矿结构(C6H13N3)PbBr4(orthorhombic, Pbca)。通过两个不同的化合物在结构和光学性质上的对比,表明有机阳离子配体对无机层结构以及杂化钙钛矿材料光学性质的影响。 在氢溴酸溶液中,组胺与卤化铅自组装成(100)取向杂化钙钛矿(C5H10N3)PbBr4 (monoclinic, P21/c),(C5H10N3)PbCl4 (monoclinic, P21/c)。得到由扭曲的共角八面体组成的钙钛矿片层。受有机配体空间位阻及氢键的影响,无机层发生一定的扭曲,从而导致激子吸收较(分别位于419 nm,339 nm)线形脂肪胺有一定程度的红移。荧光光谱中存在基于溴化铅,氯化铅杂化钙钛矿激子的特征发射峰。另外作为比较,另一个复杂的有机胺3-氨基-1,2,4-三唑,在同样的条件下与PbBr2进行组装得到的是无机组分为一曲折的链状一维结构的杂化结构(C2H2N4)PbBr3 (orthorhombic, Pna21)。 线形的二咪唑配体2,2΄-(二咪唑基-甲基)苯和4,4΄-(二咪唑基-甲基)对联苯,由于其空间位阻与氢键的影响,与卤化铅的组装得到链状骨架。2,2΄-(二咪唑基-甲基)苯与氯化铅构筑的无机骨架是由共边铅氯三角锥连成的一维链状结构(C7H8N2)PbCl3 (triclinic, P-1);与溴化铅形成类似交替排布的层状结构(C7H8N2)PbBr3 (triclinic, P-1)。4,4΄-(二咪唑基-甲基)对联苯构筑的氯化铅骨架为新奇的由共点的铅氯四方锥组成的类隧道形链(C20H21N4)Pb2Cl6•H2O (triclinic, P-1);构筑的溴化铅骨架为由共边的铅溴八面体组成的双链(C20H21N4)Pb2Br6 (monoclinic, C2/c)。形成配合物的发光为配体本身的π-π*跃迁发光。 所合成的杂化钙钛矿材料都具有较好的成膜性,利用简单的旋涂法即可得到质量较好的薄膜材料,有利于对其进行光电研究。
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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)3phenM41和Ln(dbm)3phenS15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)3phenM41和Ln(dbm)3phenS15两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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有机/无机杂化功能超薄膜是二十一世纪分子科学的重要发展前沿之一,设计具有功能性的有机/无机杂化薄膜已成为这一领域的挑战性课题。本论文分别采用Lallgmuir-B1odgett(LB)膜技术及溶胶一凝胶薄膜组装技术,将稀土无机配合物和稀土有机配合物分别与有机大分子化合物进行薄膜分子组装,对稀土配合物有机/无机杂化薄膜的光、电性质进行了研究。采用LB技术,将K11Ce(PWllO39)2·22H2O,K11Eu(PW11O39)2·25H2O,K11Gd(PW11O39)2·24H2O,K11Sm(PMo11O39)2·19H2O,K11Ce(PMo11O39)2·23H2O,K11Eu(PMo11O39)2·22H2O,K11Gd(PMo11O39)2·2OH2O,K11La(PMo11O39)2·18H2O八种稀土杂多化合物分别掺杂到聚喳琳中,得到十八胺(十八酸)/聚喳琳/稀土杂多化合物导电杂化LB膜。杂化LB膜表面的稀土杂多化合物颗粒大小在30-80nm之间。电性质研究表明,稀土杂多化合物的掺杂可使聚喳琳的导电性显著提高,且钥系稀土杂多化合物掺杂使聚哇琳的导电性增加更为显著。采用溶胶一凝胶薄膜组装技术,将K13(EuSiW11O39)2·28H2O,K13(EuGewl 1039)2·25H2O,K巧(EuBWllO39)2·22H2O,N钩SmWlo036·18H20,Na9DyS10O36·22H2O五种稀土杂多化合物分别与聚醋进行薄膜组装,得到聚醋/稀土杂多化合物溶胶一凝胶膜。荧光光谱研究表明,稀土离子在溶胶一凝胶膜中格位对称性降低,红橙比和黄蓝比发生了改变。1:11型稀土杂多化合物固体与聚酷/稀土杂多化合物溶胶一凝胶膜有不同的能量转移过程,在溶胶一凝胶膜中,配体能将能量传递给稀土离子。采用原位法将对十六烷氧基苯甲酸试及邻十七酞基苯甲酸试有机配合物分别进行了溶胶一凝胶薄膜组装,对其荧光性质进行了研究。结果表明,芳香梭酸配体与稀土诫离子有较好的能级匹配,能够有效地将吸收的能量传递给Tb3+离子,薄膜具有良好的发绿光性能。
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杂化的纳米尺寸的有机/无机化合物开辟了材料科学的新纪元。作为新型功能材料,杂化的有机/无机杂化材料由于在光学、电子、机械、防护涂层、催化、传感器、生物等方面有潜在的应用前景而在材料科学领域引起广泛关注。杂多酸(POMs)作为一种重要的无机化合物,有特异的纳米尺寸结构,优越的物理化学性质和广泛应用价值,因此多酸化合物功能材料的研究引起人们足够的重视。最近,人们把更多的注意力集中到杂化的有机/无机杂化材料范围内,如何更有序的组装杂多酸,因为它们有着更有趣的电、磁、氧化还原和光学性质。1.在4-氨基苯甲酸修饰的玻碳电极表面,我们用层层组装方法制备了六钒取代的理杂多酸(PW6V6)多层膜。表面等离子(SP)技术和循环伏安(CV)法对多层膜进行了表征。结果表明,多层膜生长均匀,平均厚度为2.8nm,并且研究了多层膜对亚硝酸根伽02一)和浪酸根(BrO3-)的催化还原活性。2.研究了通过静电吸附作用,P2W17Fe和QPvP-Os交替组装多层膜。循环伏安(CV),电化学交流阻抗谱(EIS)和紫外一可见光谱(UV-vis)研究结果表明了这种多层膜是均一稳定的。多层膜对H2O2,BrO3-和NO2-有很高的催化活性。特别是EIS成功地监测多层膜的形成过程。随着层数增长,电子传输阻抗Rc,线性增加,氧化还原电对Fe(CN)63/4的电子传输受到抑制,这进一步证实了多层膜的均一性。3,首次在4-氨基苯甲酸修饰的玻碳电极表面成功地构建了含杂多酸P2W15V3的多层膜。值得注意的是,该多层膜对BrO3-和NO2-的还原有显著的电催化活性,而且由于过渡金属钒在P2W15V3起催化作用而有很低的过电位。另外,多层膜中QPVP-O5聚合物的Os中心在抗坏血酸氧化时的催化活性仍然存在,而且通过最外层的调整,多巴胺和抗坏血酸能被分别检测,所以在多巴胺存在时它可用作检测抗坏血酸的电化学传感器。4.迄今为止,人们把更多的注意力集中在杂多酸多层膜的制备,电化学和电催化活性的研究,对杂多酸多层膜功能材料的研究却很少,我们首次够构造了发光的杂多酸多层膜,紫外可见光谱,循环伏安,电化学阻抗技术和荧光光谱证明多层膜生长均匀,室温下,多层膜的发光性能显示Eu3+的特征发射峰是5D0→7Fj(j=1,2,3,4)的跃迁。电化学阻抗谱被成功得应用于监测多层膜的沉积过程。我们发现随多层膜的逐步形成,半圆直径有规律地长大。而且,电荷迁移电阻Rc,随双层数线性增长。可以认为多层膜在基底电极上以非常均匀规律的方式沉积,Fe(CN)63/4氧化还原电对的氧化还原反应逐步被多层膜抑制。5.我们用层层组装方法成功构造了金纳米粒子多层膜,紫外可见光谱,循环伏安和原子力显微技术表征了多层膜的形成,金纳米粒子粒径大约14nm,表面粗糙度6.43nm。
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本论文通过聚甲基丙烯酸甲酯-b-聚丙烯睛嵌段共聚物同铁(III)离子络合物([PMMA-b-PAN]-Fe)制备有机一无机杂化薄膜,并利用妨M对薄膜的表面形态进行了表征。结果表明,通过控制[PMMA-b-PAN]-Fe络合物溶液热处理时间(T=120℃)及络合物溶液中精基同铁<III)离子的摩尔比率,可以得到不同表面形态的有机一无机杂化薄膜。并借助抑S对[PMMA-b-PAN〕-Fe络合物配位作用进行了研究,发现铁(III)离子与PMMA-b-PAN嵌段共聚物中的睛基配位。此外,对掺杂有FeSO4·7H2O 的均聚甲基丙烯酸甲酷(PMMA)溶液、均聚丙烯睛(PAN)溶液和FeSO4·7H2O(溶解在DMF中)溶液经不同时间热处理(T=120℃)后的薄膜表面形态进行了研究,结果发现,掺杂有FeSO4·7H2O 的PMMA 溶液经20in热处理后,薄膜的表面形态与FeS04·7H2O。溶液经20in热处理后薄膜的表面形态基本相同,而掺杂有FesO4·7H2O的PAN溶液经不同时间热处理后,薄膜的表面形态没有明显的变化。与此同时,对匡[PMMA-b-PAN]-Fe络合物高温热解制备碳材料进行了初步的研究,研究结果表明,利用PMMA-b-PAN]-e杂化薄膜炭化制备具有纳米尺寸孔洞的碳薄膜是可能的,但控制好热解条件至关重要。