【作者】 陈宁；

【导师】 卢兴；

【作者基本信息】 华中科技大学 ， 材料学， 2021， 博士

【摘要】 富勒烯为一类具有高度共轭π电子结构的笼状分子,具有优异的理化性质。溶液自组装策略可将亚纳米尺度的富勒烯分子组装为微/纳米尺度的有序结构,从而便利了富勒烯相关应用的研究和推广。在富勒烯微/纳结构的溶液自组装过程中,溶剂环境复杂,导致其形成机理仍不明确,有目的性的调控难以实现。因此,本论文采用基于溶液自组装的液液界面沉积法合成了一系列新颖的富勒烯微/纳结构,并针对溶剂在富勒烯分子自组装过程中的引导机理进行了深入探讨,为富勒烯微/纳结构的设计合成提供了借鉴,且针对所形成微/纳结构的形貌特征,对其性质也进行了相应研究。主要内容分为以下四部分:（1）富勒烯分子在液液界面处的自组装行为难以调控,导致暴露面不确定的曲面结构从未获得。而选用高粘度的异丁醇为不良溶剂,苯甲醚为良溶剂时,可调控C₆₀分子的生长行为,从而制备独特的曲面三维“大卫之星”状C₆₀微晶,解决了曲面富勒烯晶体难以制备的难题。异丁醇的高粘度使C₆₀分子的扩散受限,特定晶面难以生长为暴露面,最终形成无确定暴露面的曲面。此外,通过调整C₆₀微晶的表面曲率可有效调控其光电性质。（2）带表面缺陷的富勒烯微/纳结构在光电和催化领域备受关注,但是产量最高的C₆₀分子却由于其分子的高对称性而形成此类结构。而C₆₀分子在苯乙醚/正丙醇分别作为良/不良溶剂时,可以实现先端部后侧壁的两步生长,从而形成侧壁带裂纹的C₆₀微晶。表面裂纹的存在有助于光子吸收,从而使这些微晶的光致发光强度明显增强。此外,具有宽裂纹的微晶展现出基于静电作用的微观物质识别特性,为其生物应用奠定基础。（3）C₇₀微/纳结构的种类远不及C₆₀丰富。考虑到溶剂分子对富勒烯分子自组装行为的指导,带乙氧基的苯乙醚被选为良溶剂介入C₇₀分子的自组装过程,并促使C₇₀带状微米结构得以形成。单晶结构表明其晶格中苯乙醚的氧原子与C₇₀的六元环间存在的孤电子对-π相互作用是带状结构形成的关键,这也为其他富勒烯分子类似结构的制备提供参考。并且通过简单地改变醇种类,可调控微米带的尺寸。经45°C和60°C处理,微米带表面会出现裂纹,这使其光致发光强度进一步提升。（4）开发了一种红荧烯结晶辅助C₆₀微米片转化为纳米棒阵列的简单而又有效的策略。在预先制备的菱形C₆₀微米片上滴加红荧烯的间二甲苯溶液,待挥发完,微米片便转化为晶态红荧烯掺杂的C₆₀纳米棒阵列。当仅滴加间二甲苯溶剂时,只能形成随机分布的C₆₀纳米棒。C₆₀微米片与挥发形成的红荧烯晶体的晶面间距相匹配及两种分子间的电荷转移相互作用,促使C₆₀微米片转化为纳米棒阵列。因高度有序的阵列结构与两种分子间的电荷转移相互作用,纳米棒阵列的光电流密度较随机排列的纳米棒在紫外区提高了31.2%。更多还原

【Abstract】 Fullerenes as a class of carbon cage molecules with a highly conjugatedπ-system,possess unique physical and chemistry properties.The sub-nanometer fullerene molecules can be assembled into ordered micro-/nanostructures through solution self-assembly strategies.These structures possess the characteristics of micro-/nano materials which facilitate the research and promotion of fullerene-related applications.During the solution self-assembly process of fullerene micro-/nanostructures,the complex solvent environments result in the unclear formation mechanism,which leads to the purposeful regulation is difficult to achieve.Accordingly,in this dissertation,we obtain several novel fullerene structures using the solution self-assembly based liquid-liquid interfacial precipitation method,and then explore the guide mechanism of solvents during the self-assembly process of fullerenes.Moreover,the morphology-dependent properties of these fullerene structures have also been studied.The main results of our work are summarized as below:（1）Fullerene structures with definitely exposed facets can be synthesized easily at the liquid-liquid interface,but the structures without defined exposed facets are difficult to obtain.By selecting the high-viscosity isobutyl alcohol（IBA）/anisole as the poor/good solvents,respectively,the three-dimensional“Star of David”-shaped C₆₀ microcrystals with the unique curved surface are produced,which solves the difficulty of preparing curved fullerene crystals.The high viscosity of IBA restricts the diffusion of C₆₀,which affect peculiar facet to be exposed,thus generating the curved surface without definitely exposed facets.Furthermore,the photoelectric properties of these C₆₀ microcrystals can be regulated effectively by adjusting their surface curvatures.（2）Fullerene micro-/nanostructures with surface defects have attracted the attention in the field of photoelectric and catalysis.However,the most abundant C₆₀ is difficult to assemble into such structures due to the high symmetry.Through carefully selecting,the C₆₀microstructures with surface cracks are synthesized through the two-step growth with phenetole/n-propanol（NPA）as the good/poor solvents,respectively.The surface cracks increase the light absorption,thus enhancing the photoluminescence（PL）of these C₆₀microcrystals.Besides,C₆₀ microcrystals having wide cracks show microscopic recognition properties based on electrostatic interaction,laying the foundation for biological applications.（3）The variety of C₇₀ micro-/nanostructures is far less abundant than C₆₀ counterparts.Considering the guidance of solvents on the self-assembly of fullerene molecules,phenetole with ethoxy group is selected as the good solvent for the self-assembly of C₇₀ molecules,which generates C₇₀ microbelts under different alcoholic poor solvents.Single crystal structures show that the lone pair-πinteraction between the oxygen atom of phenetole and the hexatomic ring of C₇₀ is key to form the microbelt,which also provides a reference for the preparation of similar structures for other fullerene molecules.Besides,the size of C₇₀microbelts can be simply tuned by changing the type of alcohol.Moreover,the cracks are formed on the surface of the microbelts upon treated at 45°C or 60°C,which increases the photoluminescence intensity.（4）A simple strategy has been developed to convert C₆₀ microsheets into C₆₀ nanorod arrays with the assistance of crystallized rubrene.The rubrene-m-xylene solution is dropped on the pre-prepared C₆₀ rhombus microsheets,promoting the transformation of microsheets into crystalline rubrene-doped C₆₀ nanorod arrays upon m-xylene evaporation.However,only dropping m-xylene results in the formation of randomly distributed C₆₀ nanorods.The close match of interlayer spacing between the C₆₀ microsheets and rubrene crystals generated after evaporation,together with the charge transfer（CT）interaction between the two types of molecules,promotes the conversion from microsheets into nanorod arrays.Due to the ordered structures and the CT interaction between the two types of molecules,the photocurrent density of the nanorod arrays is improved by 31.2%in the UV region relative to the random nanorods.更多还原