EAGER: Towards Atomic-Scale Imaging of Hybrid Nanomaterials

技术综述：具有至少一位数纳米尺寸的异质结构和有机分子的参与，正在成为低成本、可印刷和柔性电子产品的无机半导体和绝缘体的激动人心的替代品。这类材料中的界面对于功能是不可或缺的，但在结构和化学上正变得越来越复杂。全有机或有机/无机杂化纳米材料的定量成像对现有的电子光学方法是一个巨大的挑战。激光脉冲原子探针层析成像(APT)是一种潜在的变革性分析工具。在NSF固态和材料化学计划的支持下，该项目将利用Pi Joester在样品制备、APT操作和光谱解释方面的经验，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。具体地说，人们建议研究三类重要材料的模型体系：i)DNA包裹的单壁碳纳米管(SWNT)作为分子电子/光学器件的自组装构件的代表。二)自组装纳米介电材料(沙子)，作为电子应用中有机薄膜的例子。三)具有金属和金属氧化物纳米颗粒有效载荷的铁蛋白纳米笼，作为混合纳米材料的例子。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包裹的单壁碳纳米管的APT成像将使系统研究DNA序列和纳米管手性对复杂几何和电子性质的影响成为可能。研究结果将为合理设计单手性SWNT纯化方案和CNTFET器件的程序化组装提供参考。可视化沙子原子级结构将极大地增强将工艺、缺陷形成和设备性能关联起来的能力。选定的模型系统是为了最大限度地与南加州大学MRSEC和南洋理工大学国际纳米技术研究所的现有研究工作产生协同效应。拟议的活动包括为从本科生到博士后的年轻研究人员提供研究培训，以及举办原子探测断层扫描暑期班，以传播项目团队以外的实践技能。非技术摘要：快速材料创新是增强美国在柔性/可打印电子产品、超低功耗或用于紧急应用的超高速电路方面的竞争力不可或缺的一部分。西北大学是全有机和低维有机/无机异质结构的领先者，如碳纳米管场效应晶体管(CNTFET)或自组装纳米介电(沙子)薄膜。然而，目前分析工具的缺陷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见的化学选择性，可能会对这一挑战提出挑战。在这个由NSF固态和材料化学计划资助的项目中，建议利用PI Joester在APT的经验，与NU的领先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。拟议工作的结果将通过促进结构-功能研究和极大地加速国家大学及其伙伴机构的创新而产生立竿见影的影响。北大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外，拟议活动的影响还将大大扩大，方法是在APT的暑期学校向项目团队以外的用户提供有关样品制备技术和APT的动手培训。

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.