EAGER: Flame Synthesis of Graphene Films

EAGER：石墨烯薄膜的火焰合成

• 批准号: 1249259
• 负责人: Stephen Tse
• 金额: $ 15万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1249259&HistoricalAwards=false
• 关键词: EAGER; Flame; Synthesis; Graphene; Films

Carbon-based nanostructures and films define a new class of engineered materials that display remarkable photonic, electrical, and mechanical properties. Graphene is a monolayer of sp2-bonded carbon atoms in a two-dimensional (2-D) structure. This layer of atoms can be wrapped into 0-D fullerenes, rolled into 1-D nanotubes, or stacked as in 3-D graphite. A novel technique to grow graphene films in open environments on substrates has been developed using multiple inverse-diffusion flames with methane as fuel. The post-flame hydrocarbon species (rich in CHm and Cn), which serve as reagents for carbon-based growth, are generated in quantities much greater than that achievable in stable, self-sustained premixed flames. Moreover, the inverse diffusion flame geometry ensures that oxygen is completely consumed at the flame front, permitting the production of high-quality films. This flame synthesis configuration is potentially transformative and breaks away from the conventional need for confined synthesis (as in standard chambered Chemical Vapor Deposition), and is capable of nanomaterials synthesis in open-atmosphere environments, affording not only scalable large volume production, but also large-area growth over different contoured surfaces (e.g. by rasterizing burner or translating substrate) at high rates. This exploratory program is aimed at increasing fundamental understanding of the mechanisms of graphene growth in flames, and utilization of that understanding to define process conditions that enable high-rate and high-quality synthesis of graphene films. Specifically, experiments will be conducted to characterize the effects of fuel composition, flame temperature, inert addition, hydrogen addition, oxygen concentration, pressure, substrate material, substrate temperature, burner-substrate distance, and other controllable process parameters on graphene growth and properties. In-situ laser-based diagnostics, including spontaneous Raman spectroscopy, laser-induced fluorescence, and laser-induced breakdown spectroscopy, will be used to determine the local growth conditions, such key gas-phase chemical species concentrations and temperature.Isolating monolayer graphene by microcleaving and discovering its amazing properties has generated intense experimental research on its fabrication. However, widespread use of graphene will require large-scale synthesis methods. Production methods that currently exist are typically expensive, require long processing times, and are limited to confined synthesis. The growth of these nanostructures and films over large areas remains especially challenging. Accordingly, it is evident that there is a strong need for better methods of synthesizing nanostructures, particularly carbon-based nanostructures. Flame synthesis has demonstrated a history of scalability and offers the potential for high-volume continuous production at reduced costs. In utilizing combustion, a portion of the hydrocarbon gas provides the elevated temperatures required, with the remaining fuel serving as the hydrocarbon reagent, thereby constituting an efficient source of both energy and hydrocarbon reactant. These aspects can be especially important as the operating costs for producing advanced materials, especially in the semiconductor industry, far exceed the equipment costs. In addition, the research affords the possibility of coating large existing structures with graphene in open environments, which is currently not possible.

基于碳的纳米结构和膜定义了一类新的工程材料，这些材料显示出了显着的光子，电气和机械性能。 石墨烯是在二维（2-D）结构中的SP2键合碳原子的单层。 该原子层可以包裹成0-D富勒烯，将其卷成1-D纳米管，也可以像3-D石墨一样堆叠。 在开放环境中，在底物上种植石墨烯膜的一种新型技术是使用用甲烷作为燃料的多种反向扩散火焰开发的。 泡后碳氢化合物物种（富含CHM和CN）作为碳基生长的试剂，其数量的产生远大于在稳定的，自我维持的预燃料中可实现的量。 此外，逆扩散火焰几何形状可确保在火焰阵线完全消耗氧气，从而允许产生高质量的薄膜。 这种火焰合成构型具有潜在的变化，并且可以摆脱限制合成的常规需求（如标准的腔室化学蒸气沉积中，并且能够在开放大气环境中纳米材料合成，不仅可以扩展大量的大量生产，而且可以使大区域的生长量相同的速率（例如，均匀的速率）（例如，均匀的速度均匀倍增）。该探索性计划旨在提高对火焰中石墨烯生长机制的基本理解，并利用该理解来定义能够对石墨烯膜的高速和高质量合成的过程条件。 具体而言，将进行实验，以表征燃料成分，火焰温度，添加惰性，添加氢，氧气浓度，压力，底物材料，底物温度，燃烧器 - 基底距离以及其他可控过程参数对石墨烯生长和性能的影响。 基于原位激光的诊断，包括自发的拉曼光谱，激光诱导的荧光和激光诱导的分解光谱法，将用于确定局部生长条件，这些关键的气相化学物种浓度和温度。通过微连接和发现其令人惊叹的物质化的实验，使单层素化烯具有固定的单层素化元，其构造实验构成了精通的实验。 但是，石墨烯的广泛使用将需要大规模合成方法。 当前存在的生产方法通常昂贵，需要较长的处理时间，并且仅限于限制合成。 这些纳米结构和电影在大区域的增长仍然特别具有挑战性。 因此，很明显，非常需要更好地合成纳米结构，尤其是基于碳的纳米结构的方法。 火焰合成证明了可扩展性的历史，并为降低的成本提供了大量连续生产的潜力。 在利用燃烧时，一部分碳氢化合物可提供所需的温度升高，其余燃料用作碳氢化合物试剂，从而构成了能量和碳氢化合物反应剂的有效来源。 这些方面可能特别重要，因为生产先进材料的运营成本，尤其是在半导体行业，远远超过了设备成本。 此外，该研究提供了在开放环境中与石墨烯涂覆大型现有结构的可能性，目前是不可能的。