光功能纳米材料的制备及其在光电转换和生物检测中的应用

【作者】 陈志钢；

【导师】 李富友； 黄春辉；

【作者基本信息】 复旦大学 ， 无机化学， 2008， 博士

【摘要】 本论文的研究工作涉及染料敏化太阳能电池（DSSCs）和稀土发光纳米材料这两部分。Ⅰ.光电功能纳米材料的制备及其在DSSCs中的应用DSSCs已经吸引了各国科学家的浓厚兴趣。为了提高固态/准固态DSSCs的光电转换效率和热稳定性,我们设计制备了两类导电率高、热稳定性好的凝胶电解质和含通道的新型TiO₂薄膜。1)纳米复合凝胶电解质利用F原子和羟基（-OH）之间的氢键（O-H…F）作用,以纳米SiO₂颗粒和含氟的离子液体为框架材料,以丁二腈或者离子液体为电解液溶剂,制备了两类热稳定性高、电导率高的纳米复合凝胶电解质。将它们组装成DSSCs,该DSSCs在室温下展现了较高的光电转换效率（5～6%）。重要的是,它们能够在一个宽的温度范围（20～80℃）正常工作,同时具有良好的长期稳定性;这些特性使该DSSCs拥有室外长期工作的前景。2)新型含通道的纳米TiO₂薄膜将直径为30-50 nm的ZnO纳米线包裹到纳米TiO₂薄膜中,随后通过盐酸腐蚀ZnO纳米线,获得了新型的含纹理通道的纳米TiO₂薄膜,其中通道由薄膜表面的裂缝和膜内直径约为41nm的孔道组成。将含通道的纳米TiO₂薄膜与固态/准固态电解质组装成DSSCs,发现这类DSSCs的光电转换效率比传统薄膜DSSCs的效率提高了15～30%。进一步研究表明引入通道有利于固态/准固态电解质渗进薄膜孔隙,从而改善界面接触/界面反应和提升DSSCs的光电性能。Ⅱ.稀土发光纳米材料的制备及其在生物研究中的应用。稀土发光纳米材料（RENPs）具有良好的化学和光学性质,是一类有潜力的生物发光标记物。RENPs生物应用的前提是制备水溶性的、表面有活性基团（如COOH,-NH₂或者-SH）的RENPs。这里我们发展了几种简易和通用的方法来制备水溶性的、功能化的RENPs。1)氧化法制备羧酸功能化的稀土上转换发光纳米材料我们发展了一个新的、通用的合成途径来将疏水的稀土上转换发光纳米材料（UC-RENPs）转化成亲水的、羧酸功能化的UC-RENPs,该途径依赖于采用Lemieux-von Rudloff试剂将UC-RENPs表面的油酸配体氧化成壬二酸配体。这种氧化过程对UC-RENPs的形貌、相结构、成分、发光等没有明显的影响。另外,UC-RENPs表面的自由羧酸不仅使其能溶于水,而且便于其与生物分子（如链亲合素）进一步连接。我们利用链亲合素功能化的UC-RENPs构建了一类高度灵敏的DNA传感器,表明这种氧化方法获得的UC-RENPs是一类有潜力的生物发光标记物。2)微乳水热法一步制备氨基功能化的稀土上转换发光纳米材料我们发展了一类微乳水热法来一步制备氨基功能化的稀土上转换发光纳米材料（UC-RENPs）。以阴离子型表面活性剂（琥珀酸二（2-乙基己基）酯磺酸钠:AOT）、正庚烷和水溶液来构建三组分反相微乳,并在水相中加入6-氨基己酸作为配体。水热处理后得到水溶性的UC-RENPs,其表面氨基密度为（9.5±0.8）×10^-5mol/g,而且该UC-RENPs样品能用于细胞上转换发光成像。3)室温反相微乳法一步制备羧酸功能化的发光纳米材料利用阳离子型表面活性剂（十六烷基三乙基溴化铵:CTAB）、正丁醇、正庚烷和水溶液构建了一类四组分的反相微乳体系。将含不同的阴阳离子的反相乳液混合,再引入含配体（戊二酸二钠）的反相微乳体系,室温下制备了水溶性的、羧酸功能化的稀土发光材料和其它材料。更多还原

【Abstract】 This thesis is composed of two parts.One part is dye-sensitized solar cells（DSSCs） and another is rare-earth nanophosphors.Ⅰ.Optoelectronic nanomaterials for dye-sensitized solar cells.DSSCs have been currently attracting widespread scientific and technological interest.To promote conversion efficiencies and thermostability of quasi-solid/solid state DSSCs,in this study,we prepared two kinds of highly conductive-thermostable gel electrolytes and novel nanocrystalline TiO₂ films with the channels for DSSCs.1).Nanocomposite gel electrolyte:By introducing the hydrogen bond（O-H…F） network upon addition of silica nanoparticles and ionic liquid containing F atom,two kinds of highly conductive-thermostable gel electrolytes can be prepared with succinonitrile or another ionic liquid as the solvent.Both kinds of DSSCs with the gel electrolytes show high solar-to-electric energy conversion efficiencies（5-6%）.Importantly,these DSSCs can work well over a wide temperature range（20-80℃）,and have excellent long-time durability,making the device viable for practical outdoor application.2) Novel nanocrystalline TiO₂ films with the textural channelsNovel nanocrystalline TiO₂ films with the textural channels are obtained for DSSCs. The textural channels consisting of the cracks on the surface and the nanopores with average diameter of about 41 nm are produced by packaging ZnO nanowires with diameter of 30-50 nm into TiO₂ films and subsequently etching ZnO nanowires by hydrochloric acid.When several quasi-solid/solid state electrolytes are used,the energy conversion efficiencies of DSSCs from novel TiO₂ films are improved by 15～30%compared to that from traditional TiO₂ films.The introduction of the textural channels facilitates better penetration of quasi-solid/solid state electrolytes into the nanopores of novel TiO₂ films and thus results in better interfacial/electrical contact and faster interfacial reaction.Ⅱ.Rare-earth nanophosphors for biological applicationsDue to their attractive chemical and optical features,rare-earth nanophosphors （RENPs） have great potential as a new kind of biological luminescent label.A prerequisite for their biological applications is to gain access to water-soluble nanoparticles bearing appropriate functional groups（such as -COOH,-NH₂ or -SH） on their surface.In this study,we have developed some simple and versatile synthesis strategies for the desired RENPs.1) Versatile oxidization strategy for carboxylic acid-functionalized RENPs:By directly oxidizing oleic acid ligands to azelaic acids（HOOC（CH₂）₇COOH） ligands with the Lemieux-von Rudloff reagent,a simple and versatile strategy has been developed for converting hydrophobic up-converting rare-earth nanophosphors （UC-RENPs） into water-soluble and carboxylic acid-functionalized analogues.This oxidation process has no obvious adverse effects on the morphologies,phases, compositions and luminescent capabilities of UC-RENPs.In addition,the presence of free carboxylic acid groups on UC-RENPs surface not only confers high solubility in water,but also allows further conjugation with biomolecules such as streptavidin.A highly sensitive DNA sensor based on streptavidin-coupled UC-RENPs has been prepared,and the demonstrated results suggest that these UC-RENPs have great superiority as luminescent labels for biological applications.2) Hydrothermal microemulsion-directed synthesis of amine-functionalized RENPs:We present the one-step preparation of amine-functionalized UC-RENPs by a modified hydrothermal microemulsion synthesis strategy.A ternary water-in-oil microemulsion,consisting of an anionic surfactant（sodium bis（2-ethyihexyi） sulfosuccinate:known as APT）,n-heptane and water,is used,and 6-aminohexanoic acid as a suitable chelating agent is added into water core.Amine-functionalized UC-RENPs can be obtained after hydrothermai treatment,and the content of free amine moieties is found to be（9.5±0.8）×10^-5 mol/g.Importantly,these UC-RENPs can be used as the label for laser scanning up-conversion luminescence imaging of Cells.3) Room temperature synthesis of carboxylic acid-functionalized nanophosphors by reverse microemulsion route.Quaternary water-in-oil microemulsion,consisting of a cationic surfactant （Cetyltrimethylammonium bromide:CTAB）,n-butanol,n-heptane and water,is used to prepare nanomaterials.By mixing two reverse micelle containing different ions or compound,and subsequently combining with another reverse micelle containing aqueous soluteion of sodium glutarate as surface ligands,carboxylic acid-functionalized RENPs and other nanocrystals can be prepared at room termperature.更多还原