Fundamental Studies of Novel Inorganic Fullerenes

这个项目的重点是研究最近发现的一类无机闭壳纳米结构，由层状结构的过渡金属二卤化物的嵌套八面体组成，预计具有离散的化学计量比。研究了二硫化钼和二硫化钼纳米八面体以及其他层状材料，如二硫化钽、二硫化Nb、二硫化钨、二硫化钼和二硫化钼的合成和性质。目前用于生产“无机富勒烯”(IF)的激光烧蚀方法将得到优化，并将探索其他方法来生产这些新结构，如弧光放电。新型IF相的结构和电子性质将用扫描探针显微镜进行研究。单个IF粒子将被成像，并通过隧道光谱测量其电子性质，无论是在环境条件下还是在超高真空环境中作为温度的函数。通过隧道光谱测量的电子态密度将决定这些新材料是半导体还是金属。此外，这些特性将作为IF结构的尺寸、形状和组成的函数来研究。由于低滚动和滑动摩擦的组合，IF材料具有潜在的润滑剂用途。本质上是单分散的半导体迭代函数系统将用于量子点应用。从事这一项目的研究生和本科生都将接触到与开辟固态化学和材料科学的新领域相关的发现的兴奋。他们将获得许多不同的合成、分离和表征技术的经验，并学会相互之间和科学界交流他们的结果。由此产生的跨学科培训将使他们为未来在化学、材料科学和纳米技术领域的学术界、工业和政府实验室的职位做好准备。

The focus of this project is to study a recently discovered class of inorganic closed shell nanostructures, composed of nested octahedra of layered-structure transition metal dichalcogenides that are expected to have discrete stoichiometries. The synthesis and properties of the molybdenum disulfide and -diselinide nano-octahedra as well as other layered materials such as tantalum disulfide, niobium diselinide, tungsten disulfide, molybdenum diselinide, and molybdenum diteluride, produced by laser ablation of the bulk material will be investigated. The currently used laser ablation method for "inorganic fullerenes" (IF) production will be optimized, and other methods for producing these novel structures such as are discharge will be explored. The structural and electronic properties of the novel IF phases will be investigated with scanning probe microscopies. Individual IF particles will be imaged and their electronic properties measured via tunneling spectroscopy, both under ambient conditions and as a function of temperature in an ultrahigh vacuum environment. The electronic density of states, measured by tunneling spectroscopy, will determine if these new materials are semiconducting or metallic. Additionally these properties will be studied as a function of size, shape and composition of the IF structures. The IF materials are potentially useful as lubricants due to a combination of low rolling and sliding friction. The intrinsically monodisperse semiconducting IFs will be useful for quantum dot applications.%%%Both graduate and undergraduate students working on this project will be exposed to the excitement of discovery associated with opening a new area of solid state chemistry and materials science. They will get experience with many different synthesis, separation and characterization techniques and learn to communicate their results to each other and the scientific community. The resulting interdisciplinary training will make them well prepared for future positions in academia, industry and government laboratories in areas of chemistry, materials science and nanotechnology.