石墨烯-碳纳米管复合薄膜透射电镜微栅及其成像、制备和表征方法研究

There are difficulties for high-resolution transmission electron microscopy (HRTEM) characterization for small-size samples using common grids.In this project,a novel grid for use in transmission electron microscopy is developed.The supporting film of the grid is composed of thin graphene films overlying a super-aligned carbon nanotube network.The composite film combines the advantages of graphene and carbon nanotube networks and has the following properties:it is ultra-thin,it has a large flat and smooth effective supporting area with a homogeneous appearance, high stability,and good conductivity.The high-resolution imaging mechanism,fabrication method and characterization method will be investigated in this project. The theory and technique methods of the single-layer atom layer supporting film grid will be founded.The graphene-carbon nanotube grid has a distinct advantage when characterizing the fine structure of a mass of nanomaterials over conventional amorphous carbon grids.Clear high-resolution transmission electron microscopy images of various nanomaterials are obtained easily using the new grids. By integrating the fully automatic fabrication process of the SACNT grids with the large-scale preparation process of graphene,batch production of the new grids can be accomplished.Due to the foreseeable unique physical and chemical properties of the new type of composite film, it is also expected to be used in semiconductor, energy, environmental protection, biological and other fields.

针对目前普通微栅进行小尺寸纳米样品透射电镜高分辨表征的困难，本项目提出一种基于单层原子支持膜的石墨烯-碳纳米管复合微栅。该微栅的支持膜是由石墨烯片复合超顺排碳纳米管网状薄膜构成。碳纳米管网起支撑作用，覆盖于其上的石墨烯用于承载样品进行高分辨分析。这种复合薄膜综合了石墨烯和碳管两种材料的优点，为纳米材料的透射电镜高分辨研究和表征提供了一种超薄的，高承载率的，高稳定性的新型微栅。本项目通过研究石墨烯承载样品的高分辨成像机制和衬度提高规律，新型微栅的制备工艺，以及性能表征和承载样品的表征实验，从而建立单原子层支持膜微栅进行高分辨表征的相关理论和技术基础。这种基于可批量制备的超顺排碳纳米管和石墨烯薄膜的微栅结构，易于实现低成本，快速和批量的制造，此外，这种复合薄膜具有可预见的独特物理，化学性质，可望应用于能源，环保，生物等领域，本项目的相关理论和技术基础研究可为其大范围应用提供保证。

针对目前普通微栅进行小尺寸纳米样品透射电镜高分辨表征的困难，本项目提出了一种基于石墨烯单层原子支持膜的石墨烯-碳纳米管复合微栅。本项目首先进行了石墨烯-碳纳米管复合薄膜的制备工艺、表征和特性研究，包括石墨烯和碳纳米管的制备、转移和表征方法等的研究。开发了一种采用超顺排碳纳米管薄膜作为支撑层，制备石墨烯-碳纳米管复合薄膜的简单高效的新方法。该方法可推广至其它二维薄膜材料的制备和转移。提出了金属薄膜辅助转移、可溶于水的有机物辅助转移等新的碳纳米管、石墨烯转移方法；开发了二次电子像直观表征碳纳米管带隙分布、水蒸气凝结辅助光学显微镜表征碳纳米管等新的表征方法。在此基础上，研制了以石墨烯-碳纳米管复合薄膜为支持膜的透射电镜微栅，进行了石墨烯-碳纳米管复合薄膜微栅承载纳米材料、生物材料的高分辨表征实验研究，实现了石墨烯-碳纳米管复合薄膜在电子显微表征领域的应用；初步进行了单原子层微栅样品透射电镜表征的超高分辨成像机制和衬度提高规律研究。还进行了石墨烯-碳纳米管复合薄膜的其它应用研究探索，包括通过石墨烯-超顺排碳纳米管复合薄膜测定石墨烯的功函数，石墨烯-超顺排碳纳米管复合薄膜作为栅极的应用研究等。本项目有关石墨烯-碳纳米管复合薄膜的制备、表征和应用研究结果，也为这种具有独特结构和性质的二维薄膜未来在半导体、能源，环保，生物等领域的应用提供了研究基础。