【作者】 张利；

【导师】 卢兴；

【作者基本信息】 华中科技大学 ， 材料学， 2017， 硕士

【摘要】 与空心富勒烯（empty fullerenes）相比,内嵌金属富勒烯（endohedral metallofullerenes,EMFs）在碳笼和内包金属原子之间存在电荷转移,因此内嵌金属富勒烯具有很多新奇的物理化学性质。这些特性使它在微纳光电器件方面具有巨大的潜在应用价值。将内嵌金属富勒烯通过有序化自组装成规则的微纳结构可以促进其在相关领域的实际应用。但是现在文献报道的金属富勒烯微纳结构的形貌依然不多,因此对其进一步研究具有重要意义。本文首次围绕金属富勒烯中的Lu₂@C₈₂,Sc₃N@C₇₈和Y@C₈₂形貌的制备调控、结构分析及光电性能方面进行了以下探索:利用掺有金属氧化物的石墨棒作为电极,通过直流电弧法合成金属富勒烯,然后通过高效液相色谱多次分离获得纯的金属富勒烯样品。实验中Lu₂@C₈₂,Sc₃N@C₇₈和Y@C₈₂均用此方法获得。通过液液界面沉积法（LLIP）,首次合成了Lu₂@C₈₂,Sc₃N@C₇₈和Y@C₈₂的一维微纳结构。实验发现,在甲苯-异丙醇（T-IPA）,间二甲苯-异丙醇（M-IPA）和二硫化碳-异丙醇（CS₂-IPA）体系下,均能获得Lu₂@C₈₂和Y@C₈₂的棒状微纳结构;在甲苯-异丙醇,对二甲苯-异丙醇体系下可以获得Sc₃N@C₇₈的棒状结构。另外,实验结果证明,通过改变富勒烯溶液浓度,溶剂比例和种类可以实现对金属富勒烯形貌的形状和大小的调控。与此同时,我们结合X射线衍射仪（XRD）和透射电子显微镜（TEM）对所获得的微纳结构进行晶型分析,并探究了其生长机理。对Lu₂@C₈₂在M-IPA体系下和Sc₃N@C₇₈在T-IPA体系下分别形成的纳米棒研究发现,与未形成有序结构的金属富勒烯溶液相比,金属富勒烯微纳结构的紫外可见光吸收光谱在可见光区域的吸收明显提高。以CS₂-IPA体系下形成的Lu₂@C₈₂六棱柱状一维结构为原料,首次研究了双金属富勒烯微纳结构的的光致发光（PL）特性。研究结果证明,有序化的微纳结构与Lu₂@C₈₂粉末相比,相同条件下PL强度明显增加。实验发现Lu₂@C₈₂和Sc₃N@C₇₈的一维纳米结构在紫外和可见光照射下均呈现优异的光电性能,证明了金属富勒烯微纳结构在微型光电器件上的应用潜力。更多还原

【Abstract】 Compared with empty fullerenes,endohedral metallofullerenes（EMFs）,a new class of hybrid molecules formed by encapsulation of metallic species inside fullerene cages,exhibit unique properties because of the presence of metals and their hybridization effect via electron transfer.Accordingly,EMFs show prospect in photoelectric and photoluminescence applications.To this end,ordered nano/microstructures are normally necessary to realize the corresponding applications.However,investigation of nanostructures of EMFs and exploration of their applications are quite limited up to now.Therefore,it is of great significance to explore ordered micro/nanostructures of EMFs.Herein,we prepared different kinds of micro/nanostructures of EMFs,including Lu₂@C₈₂,Sc₃N@C₇₈8 and Y@C₈₂.Finally,the photoelectric properties of the prepared structures were studied.The results are summarized as follows:EMFs were synthesized by a direct current arc discharge method.We isolated Lu₂@C₈₂,Sc₃N@C₇₈8 and Y@C₈₂2 from the mixing fullerenes by HPLC.We have successfully prepared one-dimensional（1D）micro/nanostructures of EMFs,including Lu₂@C₈₂,Sc₃N@C₇₈8 and Y@C₈₂,by a liquid-liquid interface precipitation method for the first time.Rodlike structures of Lu₂@C₈₂2 and Y@C₈₂2 were obtained by different kinds of mixing solvents including toluene-isopropyl alcohol（T-IPA）,m-xylene-isopropyl alcohol（M-IPA）,and carbon disulfide-isopropyl alcohol（CS₂-IPA）.Furthermore,we prepared 1D nanostructures of Sc₃N@C₇₈8 by the mixing solvents of both T-IPA and p-xylene-isopropanol alcohol（P-IPA）.In addition,the experiments demonstrate the morphologies and sizes of the structures can be controlled by changing the concentration of EMFs,the type of good solvents and the volume ratio of good to poor solvents.At the same time,we analyzed the growth process and crystal systems of the structures prepared by LLIP with XRD and TEM technologies.Compared with solution of Lu₂@C₈₂,Lu₂@C₈₂2 nanorods prepared by CS₂-IPA mixing solution exhibits broader and stronger absorption in the visible region,and the Sc₃N@C₇₈8 nanorods formed in the T-IPA solution system shows similar results.Herein,we measured the photoluminescence（PL）properties of Lu₂@C₈₂2 power and the Lu₂@C₈₂2 crystals.The PL intensity of the self-assembled Lu₂@C₈₂nanorods exhibits an obvious enhancement compared to that of Lu₂@C₈₂2 powder.In addition,the photoluminescence properties and photoelectrochemical properties of EMFs showed a remarkable enhancement after assembled into micro/nanostructures in our experiments.更多还原