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

0944479 LuGoal目标：历史上，不同维度结构的碳同素异形体（例如，三维金刚石、二维石墨和碳纳米管（轧制石墨片和0-D富勒烯）已经被大量研究。然而，一维碳链（碳炔）长期以来一直是一个不常光顾的领域，在科学界由于缺乏足够的大规模和明确的碳炔晶体样品。本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”制备碳炔。这项研究不仅有可能通过首次详细表征碳炔的晶体和电子结构来丰富碳家族树的科学知识，而且还可以为全碳电子学提供潜在的新技术方法。本项目的目标将通过五个目标来实现：1）开发一种利用激光诱导选择性断键从聚噻吩合成碳炔的方法; 2）以可扩展的数量生产定义明确且可规模化的结晶碳炔; 3）提高碳炔晶体的稳定性; 4）澄清结晶碳炔的晶体和电子结构;（5）了解碳炔的基本物理性质。PI研究表明，通过打断聚噻吩中的C-S键和C-H键可以制备碳链纳米晶。原子力显微镜和X射线衍射测量表明，形成具有准一维碳链结构的立方碳纳米晶体是可能的。基于这些初步结果，PI将使用共振激光激发选择性地断裂聚噻吩中的C-S键，这预计将以可扩展的数量产生具有明确结构的相当大的碳炔晶体。此外，PI将进行碳炔晶体的结构表征，并使用扫描隧道显微镜研究电子特性。本研究将探讨碳炔晶体的基本物理性质，以评估其在全碳电子学上应用的可能性。智力优势：这项研究将建立一个国家的最先进的方法来制备相当大的明确的碳炔晶体与可扩展的数量。成功的实施可以推动全碳电子产品的发展。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）通过获得明确定义的碳炔晶体，将很好地表征碳炔的晶体结构; 3）该工艺具有成本效益，因为它仅需要单个步骤，满足碳炔晶体的制造需求。由于PI已经成功地进行了激光与聚合物相互作用的研究，最近开发的工艺和表征设备将用于该项目。结晶碳炔的大量生产将为全碳电子、光捕获天线、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。研究成果将以各种方式发布给科学，工业和公共社区，包括互联网，期刊论文和会议。这些新知识将被纳入内布拉斯加大学林肯分校的课程（即，“ELEC 952：纳米技术介绍”）。一名来自代表性不足的少数群体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.