【作者】 李桂宝；

【导师】 刘光烨； 朴光哲；

【作者基本信息】 青岛科技大学 ， 材料学， 2010， 博士

【摘要】 富勒烯新材料具有许多不寻常的特性,在现代科技领域中存在着潜在的应用前景,例如在太阳能电池、光导、分子电子器件、药物以及催化剂等方面。目前,随着富勒烯新材料研究的不断发展,基于富勒烯纳米结构材料的研究在新材料领域中引起了广泛关注。特别是富勒烯C60是否能够在一定条件下形成新的聚集态结构,能否可控生长形成稳定形状的“管”“线”,为国际上材料科学家所关注。富勒烯C60纳米管和纳米线均具有共轭π电子结构,既保持了富勒烯C60分子的结构和性质,作为新的聚集态结构又具有准一维纳米材料的特点。本论文的主要工作是利用胶体沉淀法等制备一维富勒烯C60纳米材料,成功制备了多种不同形貌的富勒烯C60纳米材料,对它们的结构和组成进行了表征,探讨了富勒烯C60纳米管的光学各向异性、热稳定性、电化学性能和磁性能等,并讨论了一维富勒烯C60纳米材料的生长机理。论文主要内容如下：1、首次利用胶体沉淀法成功的制备了C60纳米管。通过POM、SEM、TEM、AFM等测试手段对C60纳米管进行了形貌和结构表征,结果表明：按照C60纳米管中中空结构的位置,可以分为管壁对称型C60纳米管和非对称型C60纳米管两种结构。C60纳米管的直径在300-500nm之间,最小的直径大约在150nm,长度大约为几十到几百微米,具有高的长径比。SEAD和XRD结果表明：C60纳米管的管壁是由单晶结构的C60所构成的,同时C60纳米管的生长方向是沿C60晶体的[110]面生长。通过Raman、IR谱图表明：所制备的C60纳米管不含有任何溶剂,是由纯C60分子组成。2、考察了不同的制备条件对C60纳米管生长的影响。结果表明：光照促进了吡啶-C60之间的络合反应,能够促进C60纳米管的生长。用蓝、绿光照射的C60-吡啶饱和溶液较容易培养出C60纳米管,管的含量较高,同时生成的C60纳米管外壁较光滑。超声波的照射也可以加速吡啶-C60的络合,从而缩短C60纳米管的生成时间。本工作首次利用超声波裁剪技术,制得了长径比从3到1000范围的一系列C60纳米管。3、对C60纳米管的性能进行了测试。结果表明：C60纳米管具有光学各向异性,C60纳米管在磁场中能够图案化。分别在空气和氮气气氛下对C60纳米管的热稳定性进行了测试,C60纳米管在氮气气氛中更稳定一些。对C60纳米管的电化学性能进行了测试,C60纳米管的伏安曲线上没有出现氧化峰,意味着本实验条件下还原了的C60纳米管不能被电氧化。一维结构和分子堆积状态的差异,从而导致C60纳米管的电子结构与富勒烯C60分子的电子结构不同。4、对C60纳米管和C60纳米纤维的拉曼谱图和热稳定性进行了比较。拉曼光谱结果表明：溶液状态下的C60纳米管和C60纳米纤维的拉曼光谱很相近,在同样激光条件的照射下,干燥的C60纳米管比C60纳米纤维更容易石墨化,更容易发生光聚合。可以利用拉曼光谱来区分干燥的C60纳米管和C60纳米纤维。分别在空气和氮气气氛下对C60粉末、C60纳米管和纳米纤维的热稳定性进行了研究,在空气气氛下C60纳米管、C60粉末和C60纳米纤维的初始分解温度分别约为150℃、320℃和490℃,它们的热稳定性依次增大,这是由于C60分子不同的聚集态结构造成的。在氮气气氛下,C60纳米管、C60粉末和C60纳米纤维的起始分解温度分别为160、340和700℃。温度达到900℃时,C60粉末、C60纳米管和C60纳米纤维的残留分别为：0、20%和10%。5、对C60纳米管的生长机理进行了推断：C60和吡啶分子之间发生了络合反应,形成了电子转移络合物,这是制备C60纳米管的必要条件。6、利用改良液-液界面沉积法(胶体沉淀法)快速制备了C60纳米纤维。通过POM、SEM、TEM等测试手段对C60纳米纤维进行了形貌表征,结果表明：C60纳米纤维直径比较均匀,大约在300-600nm之间,表面光滑。Raman、IR谱图表明：C60纳米纤维是由纯C60组成的。对C60纳米纤维的热稳定性进行了测试。对C60纳米纤维的生长机理进行了推断：C60和甲苯之间没有发生络合反应,即不能形成电子转移络合物,而是C60在甲苯溶液中分散形成了胶体溶液,光照能够促进胶体溶液的形成,从而加速了C60纳米纤维的生长。7、利用胶体沉淀法快速制备了C60纳米球。纳米球直径大部分为300-500nm。C60纳米球为实心结构,球的粒径大小不一；粒径大的球,表面比较光滑；粒径小的球表面比较粗糙。利用软模板法制备了C60纳微米棒,在未搅拌的情况下制备的C60纳微米棒直径在微米尺度,部分棒的尺寸在纳米级,纳微米棒的长度可以达到几十到几百微米。在搅拌的情况下C60纳米棒呈现相互重叠集聚的物理状态,直径大部分在300nm,长度为2-4微米,尺寸分布比较均匀。C60纳米棒的表面比较光洁,截面呈现六角形结构。在甲苯-C60体系中通过缓慢滴加不良溶剂的方法制备了具有树枝状和花簇状的C60纳微米结构。8.本课题组首次用富勒烯C60/C70混合物制备出C60/C70纳米纤维。对C60/C70纳米纤维进行了结构表征,结果表明C60/C70纳米纤维部分为实心结构,有的具有中空结构或者不连续的中空结构,纤维具有光学各向异性,纤维的平均直径约为1000nm,纤维表面比较光滑、管径均匀。在实验中首次发现了具有螺旋状结构的C60/C70纳米纤维,直径约为200nm。更多还原

【Abstract】 The new fullerene materials have many unusual features, which show potential applications in the fields of modern technology, such as solar cells, photoconductor, molecular electronic devices, drugs and catalysts. Currently, with the continuous development of fullerene materials research, the research of nano-structured fullerene materials in the field of novel materials has attracted widespread attentions. Fullerenes, especially C6o can form a new aggregate structure under certain conditions and form a stable shape controlled growth of the "pipe", "line", which are concerning for the worldwide materials scientists. Fullerene C6o nanotubes and nanowires both possess conjugatedπelectronic structure. These novel C60 materials not only maintain the structure and properties of fullerene molecules, but also possess the characteristics of quasi one-dimensional material. The main work of this thesis is the synthesis of one-dimensional fullerene C60 nanomaterials using colloidal precipitation method. A variety of different morphologies of fullerene C60 nanomaterials has been successfully prepared and their structure and composition were detailed characterized. The optical anisotropy, thermal stabilities, electrochemical properties and magnetic properties of fullerene C60 nanotubes were also characterized. As the same time, based on the above results, the growth mechanism of one dimensional fullerene C60 nanomaterials was discussed. The main contents were described as follows:(1) In this paper, fullerene C60 nanotubes were first successfully synthesized using colloidal precipitation. The C60 nanotubes morphology and structure was characterized by POM、SEM、TEM and AFM. The obtained results showed that the C6o nanotubes possessed two structures:the symmetry and non-symmetry wall C6o nanotubes in accordance with the position of the hollow structure. Their diameter is between 300-500nm, the minimum diameter of C6o nanotube is about 150nm, the length is about tens to hundreds of microns with high aspect ratio. The SEAD and XRD results showed that the C6o nanotube’s wall was composed of single crystal C60 molecules. The growth direction of C6o nanotubes was along the [110] surface of C6o molecules. The Raman and IR spectra confirmed that the C60 nanotubes were composed of pure C60 molecules.(2) The influence of different preparation conditions on the growth of C60 nanotubes was studied. The results showed that light can accelerated the complex of pyridine and C6o molecule and promote the growth of C6o nanotubes. It is easier to obtain C6o nanotubes using the blue and green light saturated the C60-pyridine solution, the content of nanotubes was higher, and the nanotubes’wall was smoother. Meanwhile ultrasonic irradiation can also accelerated the complex of pyridine and C60, thereby reducing the formation time of C60 nanotubes. For the first time we got a series of C60 nanotubes with the aspect ratio range from 3 to 1000 using ultrasonic cutting technology.(3) We investigated the properties of fullerene C60 nanotubes. The results showed that C6o nanotubes had optical anisotropy. At the same time, the C60 nanotubes can be patterned in a magnetic field. In addition, the thermal stabilities of C60 nanotubes were studied in air and nitrogen atmosphere respectively. The results showed that C6o nanotubes were more stable in nitrogen atmosphere. The electrochemical properties of C60 nanotubes were tested. The voltammogram oxidation peak of C60 nanotubes did not appear which means that the reduced C60 nanotubes can not be electro-oxidation under the experimental conditions. The big difference of packing state between one-dimensional structure and molecular induced the difference of electronic structure between C6o nanotubes and C60 molecular.(4) The Raman spectra and thermal stabilities of C6o nanotubes and nanofibers were compared. The Raman spectra revealed that the solution state of C60 nanotubes and C6o nanofibers were similar, the dried C6o nanotubes were more easily graphite than C6o nanofibers under the same laser irradiation conditions, and the C6o nanotubes were more likely to photo-polymerization. Therefore, Raman spectroscopy can be used to distinguish C60 nanotubes and C60 nanofibers. The thermal stabilities of C60 powders, C60 nanotubes and nanofibers were studied in air and nitrogen atmosphere respectively. The initial decomposition temperature of C60 nanotubes, C60 powders and C60 nanofibers was about 150,320 and 490℃in air atmosphere, which in turn increases of thermal stability, This is due to the different aggregation structure of C60 molecules. In nitrogen atmosphere, the initial decomposition temperature of C60 nanotubes, C60 powders and C60 nanofibers was 160,340 and 700℃respectively. When the temperature reached 900℃, the C60 powders, C60 nanotubes and C60 nanofibers residues was:0,20% and 10%.(5) The growth mechanism of C60 nanotubes was investigated. The complex reaction was occurred between C60 and pyridine molecules, and then formed a charge transfer complex, which was necessary to prepare C60 nanotubes.(6) The C60 nanofibers were rapidly prepared using modified liquid-liquid interface deposition (colloidal precipitation) method. The C60 nanofibers morphology was characterized by POM, SEM, TEM and other tests, the results showed that:C60 nanofibers diameter was uniform and their surface was smooth. The Raman and IR spectra proved that C60 nanofibers were composed of pure C60.The thermal stability of C60 nanofibers was studied. The growth mechanism of C60 nanofibers was deduced:the complex reaction between C60 and toluene did not occur, which can not form charge transfer complex. But the dispersion of C60 in toluene solution can form colloidal solution and light can promote the formation of colloidal solution, thus the growth of C60 nanofibers was accelerated.(7) Fullerene C60 nanoparticles were prepared using a colloidal precipitation method. Their diameter was about 300-500nm. The C60 nanoparticles were solid structure, the size of nanoparticles was different; the larger size of nanoparticles the surface smoother; the smaller size of nanoparticles the surface rougher. The C60 micron/nanometer rods were prepared using soft template method, their diameter was in micron scale in the case of not mixing preparation, and some of rods diameter in nanometer scale, the length of rods can reached tens to hundreds micrometers. In the case of mixing C60 nanorods showed overlapping cluster of physical state, most of the diameter was 300nm, and length of 2-4 microns, the size distribution was more uniform. The C60 nanorods surface was smooth. They showed hexagonal cross section. The flower cluster and dendritic-like structure of C60 micro/nanometer structures was prepared by slowly dropping in toluene-C60 system.(8) The C60/C70 nanofibers were synthesized with a mixture of fullerenes C60/C70 powders. The C60/C70 nanofibers were characterized. The results showed that part of C60/C70 nanofibers was solid structure, others with hollow structure or the hollow structure was not continuous. The fibers possessed optical anisotropy; the average diameter of fibers was about 1000nm, their surface was smooth. In this experiment, we first discovered spiral structure of C60/C70 nanofibers with diameters of about 200nm.更多还原