Collaborative Research: Diameter and Chirality Control and Regrowth of Single-Walled Carbon Nanotubes

提案编号：0828771（与0828824合作）主要赞助人：Pfefferle，丽莎（帕帕季米特拉科波罗斯，Fotios）机构：耶鲁大学（美国）。康涅狄格州）合作提案：直径和手性控制和单壁碳纳米管的再生长智力优点：合成有用数量的均匀（n，m）身份的单壁碳纳米管（SWNT）是一个严峻的挑战，是先进电子应用所必需的，也是高端SWNT应用所面临的主要限制。一种有吸引力的途径涉及分离小批量的给定SWNT，然后切割成“种子”，实现有效的管端催化剂模板化，并从保持原始（n，m）-手性的末端再生长。最近令人兴奋的方法，涉及分子操作和模板提出解决这种分离和再生的挑战，但这些是固有的复杂性和难以规模化，它是不清楚的种子手性是否保持和再生是否优先有利于某些物种。我们已经开发了初步的数据，它是可行的反应模板的生长催化剂上的单壁碳纳米管的结束，提供了一个更有效的和可扩展的过程的催化剂模板化过程的复杂性的实质性缓解的潜力。通过在缩短的SWNT“晶种”的内部负载催化剂，并在适当的条件下添加反应物（例如H2），我们生产具有催化剂模板的SWNT“晶种”，用于在再生长过程中有效延长，同时保持本体特性分布。两种有效的模板剂包括通过甲烷化的氢气或通过反相甲烷化的COB 2B。温度是关键，并且取决于试剂/催化剂对以及管标识。这种方法具有化学意义，因为它模拟了SWNT生长过程本身。我们提出了分散的单壁碳纳米管种子的气相再生长的原理证明。优点包括工艺可扩展性、保真度和减少后处理以降低缺陷率。再生也将使用P13 PC富集的SWNT种子进行探测，具有给定的（n，m）-丰度分布，以确定P12 PC富集的再生是否在种子尖端开始并且手性是否保持。我们将研究作为不同直径，手性和金属性的SWNT的函数的再生长过程，所产生的：（i）我们先前证明的窄直径分布的SWNT的合成和（ii）SWNT分馏的共PI根据类型，直径和手性。我们已经证明了生产不同（n，m）-丰度，窄直径分布和平均直径从0.6到1.7 nm不等的单壁碳纳米管样品的能力。拟议的努力结合互补的专业知识的PI在纳米管合成和广泛的专业化的共同PI在纳米管分离和定量（n，m）-表征使用光致发光和可调谐激光共振拉曼光谱。这种结合的专业知识将允许探索我们的再生过程的机制沿着优化。机制研究还将利用PI在反应条件下对SWNT生长催化剂进行X射线吸收分析的工作。更广泛的影响：特定（n，m）SWNT的化学生产将彻底改变SWNT设备行业。待探索的方法是廉价的，需要很少的后处理，将把高质量的单壁碳纳米管的手中，更多的研究人员。SWNT还为感兴趣的本科生提供了一个令人兴奋的研究材料：我们的活动包括开发一个实验室课程，涉及来自当地非博士授予机构的学生，参与水修复和SWNT与微生物相互作用的研究项目。学生们将看到如何单壁碳纳米管的制作，参与水溶性功能化，并在他们的家庭实验室做实验，以评估单壁碳纳米管对目标微生物的毒性。这将与合作PI参与康涅狄格州范围内的纳米技术本科生课程开发有关。这包括开发康州大学的“Nanovan项目”，其中AFM显微镜被装入货车，并驱动到高中进行现场演示，包括SWNT演示。

PROPOSAL NUMBER: 0828771 (collaborative with 0828824)PRINCIPAL INVESTIGATOR: Pfefferle, Lisa (Papadimitrakopolous, Fotios)INSTITUTION: Yale University (U. Connecticut)Collaborative Proposal: Diameter and Chirality Control and Re-growth of Single-Walled Carbon Nanotubes Intellectual Merit: Synthesizing useful quantities of uniform (n,m) identity single-walled carbon nanotubes (SWNT) is a serious challenge, necessary for advanced electronic applications and a major limitation facing high-end SWNT applications. An attractive route involves the isolation of small batches of the given SWNT, followed by cutting into "seeds", achieving effective tube end catalyst templating, and regrowth from the ends maintaining the original (n,m)-chirality. Recent exciting methodologies involving molecular manipulation and templating propose to address this separation and regrowth challenge, but these are inherently complex and difficult to scale, and it is not clear whether seed chirality is maintained and whether regrowth preferentially favors certain species. We have developed preliminary data that it is feasible to reactively template the growth catalyst on the SWNT ends, offering the potential for substantial easing of the complexity of the catalyst templating process with a more effective and scalable process. By loading catalyst on the inside of shortened SWNT "seeds", and adding reactant (e.g. H2) at proper conditions, we are producing SWNT "seeds" with catalyst templated for effective lengthening in a regrowth process with the bulk identity distribution maintained. Two effective templating reagents include hydrogen through methanation or COB2B through reverse disproportionation. Temperature is key, and depends on the reagent/catalyst pair and also on the tube identity. This approach makes chemical sense as it mimics the SWNT growth process itself. We present proof of principle of gas phase regrowth of dispersed SWNT seeds. Advantages include process scalability, fidelity and reduced post-processing for lower defect rate. Regrowth also will be probed using P13PC-enriched SWNT seeds, with given (n,m)-abundance profiles, to establish whether P12PC-enriched regrowth is initiated at the seed-tips and chirality is maintained. We will investigate the regrowth process as a function of different diameter, chirality and metallicity of SWNT, produced by: (i) our previously demonstrated synthesis of narrow-diameter distribution SWNT and (ii) SWNT fractionated by the co-PI according to type, diameter and chirality. We have demonstrated the ability to produce SWNT samples with different (n,m)-abundances, narrow diameter distribution and mean diameter varying from 0.6 to 1.7 nm. The proposed effort combines complementary expertise of the PI in nanotube synthesis and the extensive specialization of the co-PI in nanotube separation and quantitative (n,m)-characterization using photoluminescence and tunable-laser resonance Raman spectroscopy. This combined expertise will allow exploring the mechanism of our regrowth process along with optimization. Mechanism studies will also take advantage of the PIs work on X-ray absorption analysis of SWNT growth catalysts under reaction conditions. Broader Impacts: Chemical production of specific (n,m) SWNT would revolutionize the SWNT device industry. The method to be explored is inexpensive, requires little post processing and would put good quality SWNT in the hands of many more researchers. SWNT also provides an exciting material for interesting undergraduates in research: our activities include developing a lab-based course involving students from local non-PhD granting institutions, involving participation in a research project on water remediation and the interaction of SWNT with microbes. Students will see how SWNT are made, participate in functionalization for water solubility, and do experiments in their home lab to assess SWNT toxicity to a target microbe. This will be linked to the Co-PIs involvement in a Connecticut-wide course development in Nanotechnology for undergraduates. This includes developing UConn's "Nanovan-Project", where an AFM microscope is loaded into a van and driven to high schools for live demonstrations including a SWNT demonstration.