【作者】 徐军明；

【导师】 张孝彬；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2004， 博士

【摘要】 由一维紧束缚近似方法计算的纳米碳管能带结构表明：直径和螺旋度的变化会使纳米碳管从金属性到半导体之间变化；电子可以在纳米碳管中沿轴向（而不是径向）运动，表现出典型的一维量子限域效应。无缺陷的金属性纳米碳管被认为是弹道式导体，其导电性能仅次于超导体。因此，利用纳米碳管的一维电荷传输性能一直是许多研究的目标。比如，通过纳米碳管与有机功能材料进行的复合，可以充分利用纳米碳管电荷传输快的作用，从而把功能有机分子产生的载流子迅速从有机层中引出，有效降低载流子在有机分子中传输慢、自身复合严重的缺点，提高有机物的光电转换效率。以往这方面的研究以用有机物与纳米碳管的无序共混为主，其中的有机物集中在高聚物方面。结果表明，纳米碳管显著提高了有机物的电荷传输性能及光电转换性能。而有机小分子由于难溶的特点往往很难实现与纳米碳管的共混，但它们价格低和性能高，在光电器件方面的应用非常广泛，因而通过制备纳米碳管膜及定向纳米碳管膜来制备有机无机双层膜的研究具有格外重要的意义。本论文的主要工作是基于上述应用目的，实现了纳米碳管的大量制备及其应用于纳米碳管膜的制备；在氧化铝膜板、氧化硅及硅基底上制备定向纳米碳管膜的研究；对纳米碳管膜及其与有机功能材料酞菁的复合的光电性能作了初步的研究，为纳米碳管与功能有机复合材料的进一步研究做了一些基础性的前期工作。 在本论文中，作者可控制备了氧化铝模板，包括对纳米孔的直径大小及孔深的有效控制。用电沉积法在纳米孔中沉积催化剂钴。该模板用C₂H₂作碳源CVD法制备纳米碳管时，纳米孔底的钴起着催化的作用，从孔底生长出纳米碳管。由于孔的限制作用，氧化铝模板中的纳米碳管垂直于基底生长。通过沉积时间的改变可在纳米孔的底部沉积不同量的钴，并研究了钴沉积量对纳米碳管生长的影响。研究表明，钴量太少或多都不利于纳米碳管的生长；同时，钴颗粒的形状对纳米碳管形貌有显著的影响。当镀钴的条件改变时，会改变钴金属在纳米孔内的分布。CVD法实验表明，在一定的沉积条件下会使每个纳米孔中拥有多颗Co催化剂，能生长出直径小于模板的纳米孔、并保持直径均匀分布的竹节状的纳米碳管膜。 纳米碳管长出氧化铝模板外后，由于失去了纳米孔的限制作用，就会失去其原有的定向性。为了重新得到定向性好的纳米碳管膜，必须切除孔外的纳米碳管，为此作者对已制备的此类纳米碳管膜进行了超声处理。实验结果证明，随着超声时间的延长，顶部纳米碳管会逐渐被截去，从而重新得到模板中定向性很好的纳米碳管膜。此外，作者还实现了将生长在铝基板上的定向纳米碳管膜与铝基底从其底部分离，并将其反过来作为纳米碳管膜的工作面使用，这样可以得到包含定向纳米碳管的非常平整的上表面，有利于复合膜的制备和进一步的应用。 在氧化硅基底上，采用射频磁控溅射方法沉积铁催化剂膜，应用CVD法制备了定向纳米碳管。对包覆在纳米碳管的顶部和中间的催化剂颗粒进行了仔细观察，显示催化剂在纳米碳管生长过程中的应呈准液态形态，表明纳米碳管具有很强的毛细现象。对上述纳米碳管管壁的观察表明，其管壁与管轴方向并不是严格的平行关系，在管壁的石墨面上存在许多间断处。据此对这类纳米碳管的生长机制作了分析和推测。 在硅基片上旋涂Fe困03)3的乙醇溶液，经烘烤后作为催化剂用cvD法制备了定向纳米碳管。该定向纳米碳管膜中的碳管直径较大，而内径在loonln以上。由于催化剂膜层的特殊性，NH3处理对定向纳米碳管的制备有着非常重要的影响。 采用一种方法简单的燃烧法，合成了可大量制备多壁纳米碳管的Fe/Mo舰90催化剂。该催化剂CVD法生长纳米碳管（30分钟）时，产量能达到原催化剂重量的40倍左右。用SEM和TEM对制备的产物进行了表征，发现它们皆以束状形式存在，且碳管质量较高。作者观察并研究了纳米碳管的产量及质量与生长时间的关系。对Fe肠以o从90催化剂在纳米碳管生长气氛中的变化过程作了详细的分析和研究。发现:在纳米碳管生长初期，催化剂会迅速的分解成片状，然后在这些片状催化剂上出现纳米小颗粒，最后生长出纳米碳管束;如对该催化剂先在HZ气氛下进行还原处理再生长纳米碳管，则所制备的纳米碳管呈分散状。用XRD考察了原始催化剂、还原后的催化剂及在生长过程中的催化剂的晶体结构变化，探讨了该种催化剂对于生长纳米碳管束及还原后转变为分散状纳米碳管的机理。 在AAO模板上合成的定向纳米碳管膜上，真空蒸镀了酞著铜膜用以制备纳米碳管/酞著铜复合膜。结果表明，酞善铜能在纳米碳管表面均匀沉积。当沉积厚度小时，由于纳米碳管膜自身表面的起伏而使酞蓄铜膜不连续，通过增加酞著铜的沉积厚度最终能获得连续和平整的沉积后表面。同时，采用旋涂法也获得了纳米碳管上表面平整的酞著铜膜。测定了纳米碳管膜及其复合膜的光谱吸收性能及电学性能;测定了AI/定向纳米碳管/纳米碳管+CuPc/Au复合膜层的I一V曲线;测定了以定向纳米碳管膜或非定向纳米碳管膜为基底，酞蔷铜作光生层，踪作传输层的功能分离型器件的光电导性能。在此基础上，?更多还原

【Abstract】 The energy band structure of carbon nanotubes calculated by 1-D tight-binding model indicates that carbon nanotubes can behave either as a metal or semiconductor depending on their diameter and helicity. Electrons are bound into the one dimensional in the carbon nanotubes, that is, electrons can transport in the axial and not in the radial, it is a typical quantum confinement effect. So defect-free carbon nanotubes can be considered as ballistic conductor and their conductivity is only lower than superconductors. So, the use of its charge conductivity is the one of most goals for carbon nanotube researches. Synthesis of carbon nanotube composites with organic is one of effective ways to overcome the obstacles of the intrinsic low charge mobility of organic marterials. When a functional organic material produces charge carriers under the light, the local recombination of charge carriers is usually rather serious, which will lower the effectiveness of the devices greatly. When the carbon nanotubes-organic composite is obtained, the carbon nanotubes can efficiently draw the charges from the organic own to their high transport ability, so that to improve the capability of photo-electricity conversion. Up to now researches have been focused on the mixture of organic and carbon nanotubes and the results show that the charge transport and photo-electricity conversion ability has been improved. Most of organic materials used in these mixtures composite are polymers. Polyatomic organic, especial organic dyes, is hard to be used in this way because of their low solubility. But they are useful for organic devices because of their low price and high performance. So organic and carbon nanotubes separated double-layer device is our goal to make them as a composite. In this thesis, the aligned carbon nanotubes and common carbon nanotubes film were prepared; the composite of carbon nanotube films with organic dyes using vacuum vapor deposition were obtained and their performances were primarily studied; a high efficient way to produce carbon nanotubes was also presented.In this thesis, AAO (aluminum anodic oxide) template was prepared under acontrollable way, to control the diameter and depth of nanopore columns on AAO film. Catalyst was electro-deposited into the bottom of the pores. Carbon nanotubes can be produced from these catalysts along the pores using CVD method. So, carbon nanotubes were normal to the substrate own to the confinement of these pores. The effect of quantity of deposited cobalt on growth of the aligned carbon nanotubes was studied. The effect of shape of cobalt in the pores on the carbon nanotubes was also examined. When the condition of electro-deposition was changed, the distribution of cobalt in the bottom is changed to be several separate grains but only one. The carbon nanotubes from these catalysts were a very bamboo-shaped, with a narrow distribution of the diameter, but much smaller than that of pores.When the carbon nanotubes grew out of the pores, their alignment was lost gradually without the confinement of pores. Sonication treatment was adopted to cut the carbon nanotubes out of the template. The results showed that the top of carbon nanotubes would be shortened gradually and the aligned carbon nanotubes could be got again. Another way was used to obtain smooth surface of aligned carbon nanotubes, in which the bottom near to substrate aluminum was converted to the surface as a working face.Aligned carbon nanotubes on silicon or silicon oxide is obtained. Catalyst was deposited using radio frequency magnetic sputtering technique and grew carbon nanotubes using CVD method. The catalyst on the top and middle of carbon nanotubes was observed carefully, it is believed that the catalyst will become quasi-liquid state and the carbon nanotubes have strong capillarity phenomena in the growth. The wall of carbon nanotubes was found not to have the same orientation to their axial, and lots of linear fault in their inner wall is observed. According to these observations, a growth mechanism was p更多还原