EAGER: Synthesis of One-Dimensional Carbon Chains by Selective Bond Breaking in Polymers

目标：历史上，不同维度结构的碳同素异形体（例如，3d钻石，2d石墨和碳纳米管-轧制石墨片，以及0-D富勒烯）已经被大量研究。然而，由于缺乏足够大的、定义明确的碳链晶体样品，一维碳链（carbyne）长期以来一直是科学界的一个冷门。该项目的主要目标是通过激光辅助合成工艺从聚合物前体“聚噻吩”生产碳炔。这项研究不仅有可能通过首次对碳的晶体和电子结构进行详细的表征来丰富碳家族树的科学知识，而且还可能为全碳电子技术提供潜在的新技术途径。本项目将通过五个目标来实现目标：1)开发一种利用激光诱导选择性断键从多噻吩中合成碳炔的合成方法；2)以可扩展的数量生产定义明确且相当大的晶体碳；3)提高碳炔晶体的稳定性；4)阐明碳炔晶体的晶体结构和电子结构；5)了解碳炔的基本物理性质。PI表明，通过破坏聚噻吩中的C-S键和C-H键可以制备碳链纳米晶体。原子力显微镜和x射线衍射测量表明，具有准一维碳链结构的立方碳纳米晶体是可能形成的。基于这些初步结果，PI将使用共振激光激发选择性地破坏多噻吩中的C-S键，这有望产生具有明确结构的大规模碳炔晶体。此外，PI将对碳炔晶体进行结构表征，并使用扫描隧道显微镜研究其电子特性。研究了碳晶体的基本物理性质，以评估其在全碳电子器件中的潜在应用。智力优势：这项研究将建立一种最先进的方法来制备具有可扩展数量的相当大的定义良好的碳炔晶体。成功的实施将推动全碳电子技术的发展。与目前使用的工艺相比，待开发的工艺具有以下优点：1)所提出的方法通过消除有害溶液而对环境友好；2)通过得到定义明确的碳炔晶体，可以很好地表征碳炔的晶体结构；3)该工艺仅需要一步，满足碳炔晶体的制造需求，具有成本效益。由于PI之前已经成功地进行了激光与聚合物相互作用的研究，因此最近开发的工艺和表征设备将用于该项目。晶体碳的大规模生产将为全碳电子、光收集天线、抗氧化和防腐材料等广泛的工程应用提供知识基础和实用方法。研究成果将通过互联网、期刊论文、会议等多种方式向科学界、产业界和公众发布。这些新知识将被纳入内布拉斯加州大学林肯分校的课程中（即“ELEC 952：纳米技术导论”）。一名来自少数族裔的研究生和两名本科生将参与这个项目。

0944479LuGoal & Objectives: Historically, carbon allotropes of different dimensional structures (e.g., 3-D diamonds, 2-D graphite and carbon nanotubes - rolled graphitic sheets, and 0-D fullerenes) have been copiously studied. However, 1-D carbon chains (carbyne) have long been an unfrequented zone in scientific community due to the absence of sufficient sizeable and well-defined carbyne crystal samples. The primary goal of this project is to produce carbyne from a polymeric precursor 'polythiophene' through laser-assisted synthesis process. This research has the potential to not only enrich scientific knowledge of the carbon family tree by enabling for the first time a detailed characterization of the crystal and electronic structures of carbyne, but also allow for the potential new technological approaches to the all-carbon electronics. The goal of this project will be accomplished through five objectives: 1) to develop a synthesis method to obtain carbyne from polythiophene using laser-induced selective bond-breaking; 2) to produce well-defined and sizeable crystalline carbyne in scalable quantities; 3) to improve stability of carbyne crystals, 4) to clarify crystal and electronic structures of crystalline carbyne; and 5) to understand the fundamental physical properties of carbyne. The PI has shown that carbon-chain nanocrystals could be prepared by breaking the C-S and C-H bonds in polythiophene. Atomic force microscopy and X-ray diffraction measurements suggested that the formation of cubic carbon nanocrystals with a quasi-1-D carbon-chain structure is possible. Based on these preliminary results, the PI will selectively break the C-S bonds in polythiophene using resonant laser excitation, which is anticipated to produce sizeable carbyne crystals with well-defined structures in scalable quantities. Furthermore, the PI will carry out structural characterization of the carbyne crystals and investigate the electronic properties using scanning tunneling microscopy. Fundamental physical properties of the carbyne crystals will be investigated correspondingly to evaluate the possibility of potential applications in all-carbon electronics. Intellectual Merit: This research will establish a state-of-the-art approach to preparing sizeable well-defined carbyne crystals with scalable quantities. Successful implementation could advance all-carbon electronics. Compared to currently used processes, the process to be developed has these advantages: 1) the proposed method is environmentally friendly by eliminating hazardous solutions; 2) by obtaining well-defined carbyne crystals, the crystalline structure of carbyne will be well characterized; 3) the process is cost-effective because it requires only a single step, meeting manufacturing needs of carbyne crystals. Because the PI has successfully undertaken previous research on laser interactions with polymers, the process and characterization equipment recently developed will be used in this project Broader Impacts: This project will benefit social and educational communities. The mass-production of crystalline carbyne would provide a knowledge base and practical approaches for a wide range of engineering applications, such as the all-carbon electronics, light harvesting antenna, and antioxidant and anticorrosive material. The research results will be released to scientific, industrial, and public communities in various ways, including the internet, journal papers, and conferences. This new knowledge will be incorporated into courses at the University of Nebraska-Lincoln (i.e., 'ELEC 952: Introduction to Nanotechnology'). One graduate student from an underrepresented minority group and two undergraduate students will work on this project.