纳米尺度下材料尺寸对于电子关联强度的影响

Strongly-correlated transition metal oxide nanostructures are playing an increasingly important role in the performance of fuel cells, Li-ion batteries, photovoltaic and catalytic devices, as well as functionalized hosts for drug delivery. The electronic structure of these nanoparticles is not fully understood. We propose to study these transition metal oxides in both bulk phase and nanostructures using soft X-ray spectroscopy. We will use these measurements to determine the electronic structure of these materials, and the influence that sample size has on electron correlation strength. The physics behind strongly correlated systems like transition metal oxides is not fully understood, and the physics of transition metal oxide nanostructures is even less understood. We are perfectly situated to combine the recent advances in thin film and nanostructure synthesis techniques with recent advances in synchrotron excited X-ray spectroscopy to finally resolve some of these puzzling questions. The proposed research has never before been attempted, but is finally feasible and will produce exceptional research results that will be valuable to solid state physics, materials engineering, and optimizing device performance. The applicant is a world-class expert in soft X-ray spectroscopy and electronic structure calculations. The applicant's experience in these areas will ensure the success of the proposed research. These results will contribute original research into the physics of strongly correlated materials, and help explain how these materials influence the performance of devices.

强关联过渡金属氧化物在燃料电池、锂电池、光伏及催化器件、药物输送载体等领域有着越来越广泛的应用。对于这些材料在纳米尺度下的电子结构人们尚不明确。我们计划通过利用同步辐射软X射线光谱技术，结合传统常规实验，以及理论模拟，研究这些过渡金属氧化物体材料和纳米材料的电子结构。从而得出在微尺度下，材料的尺寸和形貌的变化对于电子关联强度的影响。人们对于强关联过渡金属氧化物尤其是其纳米结构的物理性质还不甚了解，我们此项工作的重要和创新之处体现在把当今迅速发展的材料纳米合成技术与同步辐射光谱表征技术相结合，分析材料的基本电子结构。基于申请人团队在软X射线光谱实验和计算领域的丰富经验和相关前期研究成果，通过对纳米材料的电子结构的成功解析，将对于固体物理、材料工程、以及器件性能优化等各个领域都有重要作用。实验结果将加深人们对强关联材料物理的认识，并为这些材料对于器件表现的影响提供合理的解释。

金属氧化物纳米材料在离子电池和光伏器件等应用中起到越来越重要的作用。然而人们对这些纳米材料的电子结构并没有完全掌握，尤其是材料中缺陷以及共存的晶相对于材料性质对于材料性质的影响程度。在本课题中，我们利用X射线光谱结合从头计算的方法，研究了金属氧化物纳米材料的电子结构以及其对器件效率的影响。我们的工作在同行审阅国际高水平期刊上发表数篇，同时我们的工作进一步推广了利用同步辐射光谱研究纳米材料性质对器件效率影响的方法。