Synthesis Of Solvated C₆₀ And Investigations Of Their Properties Under High-Pressure

Carbon has become a superstar in the fields of material science, chemistry, andcondensed matter physics since the discovery of C60in middle of1980’s. Several newcarbon allotropes, including fullerenes (C60, C70, etc.), carbon nanotubes, andgraphene have been discovered and subjected to study in the past few decades. Withinthe carbon family, fullerenes have very unique closed-cage structure and can betreated as zero dimensional materials, which have many fascinating properties. Thefamily includes C20, C36, C60, C70, and other compounds. They have a wide range ofproperties and considerable potential in applications such as energy storage and solarcells.C60is one of the most important members of the carbon family. Its’ physicalproperties under high pressure have been studied intensively. The fact that fullerenescan generate solvates when they crystallize from solvents is of particular interest.Many studies have focused on the growth and characterization of solvated fullerenes.However, no high-pressure structural studies on this kind of fullerene materials werecarried out until2012. High-pressure structural investigations were first performed onsolvated fullerenes and this family was found to behave very differently from pureand alkali-doped fullerenes. Since that, the high pressure studies about this kind ofcarbon materials have become a hot topic. But this is just a beginning. More researchand explore on this topic are highly expected. This thesis is mainly focused on thephysical properties of the solvated fullerenes under high-pressure conditions, such aspolymerization.C60polymerized under high pressures. C60cages collapse when the pressurehigher than30GPa, and the crystalline structure becomes amorphous. Solvatedfullerenes display some unique properties, which changed our understanding offullerenes. In this paper, we use the solution evaporation method fabricated two kinds of solvated C60. They are C60·TCAN（1,1,2-trichloroethane）and C60·mesitylene.Raman spectroscopy, Infrared Radiation analysis and X-Ray diffraction were all usedto investigating the properties of the samples under high pressures.The incorporation of guest molecules into the host C60lattice changes its crystalstructure. The original fcc structure transform into orthorhombic system. There areweak van der Waals interactions between the solvent molecules and C60, and themolar ratio of the two kinds of molecules is1:1in both solvated C60.Two adjacent C60molecules in the solvate C60·TCAN crystals were polymerizedinto C60dimer under high pressures. But the C60molecules in the C60·mesitylenecrystals do not polymerized under high pressures. C60cages in the two solvatedcrystals collapsed into fragments involving pentagon and hexagon rings at32GPa and36GPa respective. At higher pressure, the crystalline structure becomes amorphous.C60·TCAN does not have a phase transition up to38.7GPa, preserving theorthorhombic periodicity. The C60·TCAN became long range ordered amorphouscarbon clusters. The bond transformed from sp2to sp3partly.