EAGER: Towards Atomic-Scale Imaging of Hybrid Nanomaterials

技术概述：具有至少一个个位数纳米尺寸的异质结构，以及有机分子的参与，正在成为无机半导体和绝缘体的令人兴奋的替代品，用于低成本，可印刷和柔性电子产品。这些材料中的界面是功能不可或缺的，但在结构和化学上变得越来越复杂。全有机或有机/无机杂化纳米材料的定量成像是现有电子光学方法的一个巨大挑战。激光脉冲原子探针断层扫描（APT）正在成为一种潜在的革命性分析工具。在这个由NSF固态和材料化学计划支持的项目中，PI Joester的经验将在样品制备，APT操作和光谱解释中得到利用，以建立APT的范围，用于从单个纳米颗粒到器件的新兴有机和有机/无机杂化材料的原子尺度表征。具体来说，建议研究三种重要材料的模型系统：1)dna包裹的单壁碳纳米管（SWNT）作为分子电子/光学器件自组装构建块的代表。自组装纳米电介质（SANDs）作为有机薄膜在电子应用中的例子。以金属和金属氧化物纳米粒子负载的铁蛋白纳米笼为例。在每种情况下，APT都有可能极大地促进未来的结构-功能分析。例如，DNA包裹的SWNT的APT成像将能够系统地研究DNA序列和纳米管手性对复杂几何和电子特性的影响。结果将为单手性SWNT净化方案的合理设计和CNTFET器件的程序化组装提供输入。可视化的SAND原子尺度结构将极大地提高处理、缺陷形成和器件性能的关联能力。模型系统的选择是为了最大限度地与北大纳米技术研究中心和国际纳米技术研究所的现有研究工作产生协同作用。拟议的活动包括对从本科生到博士后的年轻研究人员进行研究培训，以及在原子探针断层扫描方面的暑期学校，以传播项目团队以外的动手技能。非技术总结：快速的材料创新是不可或缺的，以提高美国在柔性/可印刷电子，超低功耗，或超高速电路的紧急应用竞争力。西北大学正在引领全有机和低维有机/无机异质结构的发展，如碳纳米管场效应晶体管（cntfet）或自组装纳米介电薄膜（SAND）。然而，当前分析工具的缺点阻碍了这些非常规电子材料潜力的实现。激光脉冲原子探针层析成像（APT）是一种原子尺度的定量化学成像工具，具有无与伦比的空间分辨率和无偏化学选择性，可能会面临挑战。该项目由美国国家科学基金会固态和材料化学项目资助，拟利用PI Joester在APT的经验，与北大的主要专家和中心密切合作，研究0D， 1D和2D混合电子纳米材料的模型系统。建议的工作成果将会立即产生影响，促进结构功能研究，并大大加快北大及其合作院校的创新。受影响的研究领域包括能源材料、纳米电子学、传感器、光学和自旋电子器件。除了培训下一代科学家和工程师之外，通过在APT上的暑期学校向项目团队以外的用户提供样品制备技术和APT的实践培训，拟议活动的影响将大大扩大。

TECHNICAL SUMMARY:Heterostructures with at least one single digit nanometer dimension, and participation of organic molecules, are emerging as exciting alternatives to inorganic semiconductors and insulators for low cost, printable, and flexible electronics. Interfaces in such materials are integral to function, but are becoming increasingly complex in structure and chemistry. Quantitative imaging of all-organic or hybrid organic/inorganic nanomaterials is a formidable challenge to established electron optical methods. Laser-pulsed atom probe tomography (APT) is emerging as a potentially transformative analytical tool. In this project, supported by the NSF Solid State and Materials Chemistry Program, the experience of PI Joester will be leveraged in sample preparation, APT operation, and spectral interpretation to establish the scope of APT for the atomic-scale characterization of emergent organic and organic/inorganic hybrid materials from single nanoparticles to devices. Specifically, it is proposed to investigate model systems for three important classes of materials: I) DNA-wrapped single wall carbon nanotubes (SWNT) as representatives of self-assembled building blocks for molecular electronic/optical devices. II) Self-assembled nano-dielectrics (SANDs) as examples for organic thin films in electronic applications. III) Ferritin nanocages with metallic and metal oxide nanoparticle payloads as examples for hybrid nanomaterials. In each case, APT has the potential to greatly facilitate future structure-function analyses. For example, APT imaging of DNA-wrapped SWNT will enable systematic investigation of impact of DNA sequence and nanotube chirality on the complex geometry and electronic properties. Outcomes will provide input for rational design of single chirality SWNT purification schemes and programmed assembly of CNTFET devices. Visualizing SAND atomic scale structure will dramatically enhance the ability to correlate processing, defect formation, and device performance. Model systems were selected to generate maximum synergy with existing research efforts at the NU MRSEC and the International Institute for Nanotechnology at NU. Proposed activities include research training for young investigators from undergraduates to postdocs and a summer school in atom probe tomography to disseminate hands-on skills beyond the project team.NON-TECHNICAL SUMMARY:Rapid materials innovation is integral to enhancing US competitiveness in flexible/printable electronics, ultra-low power, or ultra-high speed circuits for emergent applications. Northwestern University is leading the development of all-organic and low dimensional organic/inorganic heterostructures such as carbon nanotube field effect transistors (CNTFETs) or self-assembled nanodielectric (SAND) thin films. However, shortcomings of current analytical tools hinder realization of the potential of these unconventional electronic materials. Laser-pulsed atom probe tomography (APT), an atomic scale quantitative chemical imaging tool with unrivaled spatial resolution and unbiased chemical selectivity, may rise to the challenge. In this project, funded by the NSF Solid State and Materials Chemistry Program, it is proposed to leverage the experience of PI Joester in APT to investigate model systems for 0D, 1D, and 2D hybrid electronic nanomaterials in close collaboration with leading experts and centers at NU. Outcomes of the proposed work will have immediate impact by facilitating structure-function studies and greatly accelerating innovation at NU and its partner institutions. Research areas impacted at NU include energy materials, nano-electronics, sensors, optical, and spintronic devices. In addition to training the next generation of scientists and engineers, the impact of the proposed activities will be significantly broadened by providing hands-on training in sample preparation techniques and APT to users outside the project team in a summer school on APT.