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

建议编号：0828771(与0828824合作)主要研究员：Pfefferle，Lisa(Papadimitrakopolous，Fotios)机构：耶鲁大学(美国康涅狄格州)合作建议：单壁碳纳米管的直径和手性控制及再生长智力优点：合成有用数量的均匀(n，m)身份的单壁碳纳米管是一个严峻的挑战，对于先进的电子应用是必要的，也是高端碳纳米管应用面临的主要限制。一种吸引人的方法是分离小批量的单壁碳纳米管，然后切割成“种子”，实现有效的管端催化剂模板，并从两端重新生长，保持原始的(n，m)手性。最近涉及分子操纵和模板的令人兴奋的方法提出了解决这一分离和再生挑战的方法，但这些方法本身就很复杂，难以规模化，而且尚不清楚种子手性是否保持以及再生是否优先有利于某些物种。我们开发的初步数据表明，在单壁碳纳米管末端反应模板化生长催化剂是可行的，这为通过更有效和可扩展的工艺大幅降低催化剂模板化过程的复杂性提供了潜力。通过在缩短的单壁碳纳米管“种子”的内部装载催化剂，并在适当的条件下添加反应物(例如氢气)，我们正在生产具有催化剂模板的单壁碳纳米管“种子”，以在保持体相分布的情况下在再生长过程中有效地延长。两种有效的模板试剂包括甲烷化氢气或反歧化COB2B。温度是关键，它取决于试剂/催化剂对，也取决于管子的一致性。这种方法在化学上是有意义的，因为它模拟了单壁碳纳米管本身的生长过程。我们给出了分散的单壁碳纳米管种子气相再生长原理的证明。优点包括过程可伸缩性、保真度和减少后处理以降低缺陷率。还将使用具有给定(n，m)丰度分布的富含P13PC的SWNT种子来探索再生，以确定富含P12PC的再生是否在种子顶端启动并保持手性。我们将研究不同直径、手性和金属性的单壁碳纳米管的再生长过程，这些单壁纳米管是由(I)我们先前展示的窄直径分布的单壁碳纳米管的合成和(Ii)由共聚PI根据类型、直径和手性分级得到的单壁碳纳米管。我们已经证明了制备不同(n，m)丰度、窄直径分布和平均直径在0.6到1.7 nm之间的单壁碳纳米管的能力。建议的工作结合了PI在纳米管合成方面的互补专业知识，以及co-PI在纳米管分离和利用光致发光和可调谐激光共振拉曼光谱进行定量(n，m)表征方面的广泛专业性。这种结合的专业知识将使我们能够探索我们的再生过程的机制以及优化。机理研究还将利用PI在反应条件下对单壁碳纳米管生长催化剂进行X射线吸收分析的工作。更广泛的影响：特定(n，m)单壁碳纳米管的化学生产将给单壁碳纳米管设备行业带来革命性的变化。要探索的方法是廉价的，需要很少的后处理，并将把高质量的单壁碳纳米管提供给更多的研究人员。SWNT还为感兴趣的本科生提供了令人兴奋的研究材料：我们的活动包括开发一门以实验室为基础的课程，让来自当地非博士授予机构的学生参与，参与一个关于水修复和SWNT与微生物相互作用的研究项目。学生们将看到SWNT是如何制作的，参与水溶性的功能化，并在他们的家庭实验室中进行实验，以评估SWNT对目标微生物的毒性。这将与联合PIS参与康涅狄格州范围内为本科生开发的纳米技术课程有关。这包括开发康涅狄格州大学的“Nanovan项目”，在这个项目中，AFM显微镜被装载到一辆面包车上，然后开车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.