石墨烯及其复合材料专题 序

<正>石墨烯是由碳原子共轭构成的具有单原子层厚度的二维晶体,是目前已知的最薄的材料,其发现者也因此获得2010年的诺贝尔物理学奖。石墨烯独特的二维片层结构赋予其许多独特的性能,包括优异的导电性、导热性、透光性、力学性能以及巨大的比表面积,使其一经发现便成为碳家族中的明星材料,引发了全球范围的研究热潮。目前,石墨烯及其复合材料在光电器件、储能、光/电催化、传感、热电以及聚合物增强等方面展现出巨大的应用前景。据2015年     

石墨烯的制备与应用研究进展

石墨烯是由单层碳原子构成的新型二维晶体材料.在过去的几年里,这种独特的单原子层结构展现了许多奇特的物理化学性质,并且已经在微电子、量子物理、材料和化学等领域表现出优异的性能和广泛的应用前景,使碳材料继碳纳米管后再次成为国内外的研究热点.本文简要概述了石墨烯的性质、制备方法以及潜在应用,并对它的未来发展做了展望.     

类石墨相氮化碳二维纳米片的制备及可见光催化性能研究

以三聚氰胺为原料制备类石墨相氮化碳(g-C3N4),采用球磨与超声联用技术制备g-C3N4二维纳米片. 利用X 射线衍射光谱(XRD)、紫外-可见漫反射(UV-Vis)光谱、扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)、荧光(PL)光谱等分析手段对制备的催化剂进行了表征. 结果表明: g-C3N4二维纳米片具有与体相g-C3N4相同的晶体结构,片层结构仅有5个原子层厚.g-C3N4二维纳米片增加了对可见光的吸收,提高了光生电子-空穴对的分离效率.以染料罗丹明B的降解反应研究了g-C3N4二维纳米片在可见光下的催化性能. 结果表明,球磨超声1 h后制备的g-C3N4二维纳米片表现出最佳的光催化性能, 150 min 内对罗丹明B的降解率高达94%,是体相g-C3N4的2 倍.     

类石墨烯二维材料及光电器件应用研究进展

二维层状材料是具有单原子层或几个原子层厚度的平面材料,有着特殊的物理化学性能,在光电功能器件、吸附与分离、催化等领域具有重要应用前景,是目前国际研究的前沿和热点领域之一。其中,石墨烯是最先受到人们重视的二维材料,随即以过渡金属硫化物为主的类石墨烯二维光电功能材料也被广泛研究。近年来黑磷的发现也极大促进了二维光电材料的研究和发展。二维光电材料中石墨烯及类石墨烯硫化物的研究及其光电功能器件应用现状进行简单综述,并对其应用趋势进行展望,为光电材料研究领域的研究提供参考。     

功能化石墨烯材料在气体检测方面的应用研究进展

石墨烯是一种具有单原子层厚度的二维蜂窝状碳材料,由于其具有奇异的比表面积效应、光电效应和机械强度等优点,在能源、环境、军事和航天等领域得到了大量的研究。石墨烯材料的功能化可对其结构、物化性质和光电性质等方面进行有益调整,从而拓宽了其对化学物质的检测范围。主要综述了近期利用化学改性、纳米颗粒修饰和聚合物复合方法对石墨烯材料进行功能化改性的研究进展,以及功能化石墨烯材料在提高灵敏度和选择性等气体传感特性方面的应用,并对该领域存在的挑战和前景进行了展望。     

类石墨相氮化碳二维纳米片的制备及可见光催化性能研究

以三聚氰胺为原料制备类石墨相氮化碳(g-C_3N_4),采用球磨与超声联用技术制备g-C_3N_4二维纳米片。利用X射线衍射光谱(XRD)、紫外-可见漫反射(UV-Vis)光谱、扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)、荧光(PL)光谱等分析手段对制备的催化剂进行了表征。结果表明:g-C_3N_4二维纳米片具有与体相g-C_3N_4相同的晶体结构,片层结构仅有5个原子层厚。g-C_3N_4二维纳米片增加了对可见光的吸收,提高了光生电子-空穴对的分离效率。以染料罗丹明B的降解反应研究了g-C_3N_4二维纳米片在可见光下的催化性能。结果表明,球磨超声1h后制备的g-C_3N_4二维纳米片表现出最佳的光催化性能,150min内对罗丹明B的降解率高达94%,是体相g-C_3N_4的2倍。     

石墨烯纳米复合材料在光催化应用中的研究进展

石墨烯即"单层石墨片",是近年来人们发现和合成的具有独特的单原子层、二维晶体结构的纳米材料.利用石墨烯与半导体材料复合以提高光催化活性,已成为新型光催化研究的热点之一.对石墨烯及其应用进行了简单的叙述,重点报道了石墨烯在光催化制氢、光催化降解和光电转换应用方面的研究动态,以及用不同方法合成的石墨烯光催化复合材料,为以后石墨烯与其他材料的复合提供了实验依据.     

两片二维石墨使纳米尺寸电子器件中噪音降低

美国IBM公司华逊研究中心开发出一种降低电信号干扰的办法。graphene是一种二维单原子层石墨，当将其收缩几个原子的长度时即可使噪音减小。现在器件越做越小，材料附近出现的电信号干扰妨碍了纳米尺寸电子器件的性能提高。当在第一片graphene后再加上另一片时，电噪声可明显降低。这使未来的纳米电子学的前景更为看好。     

二维碳质材料的制备和应用

二维碳质材料具有碳质材料来源广泛、化学稳定性高、电学性质可调控等优点,而且二维构型的表面效应、小尺寸效应等使其具有特殊的光、电、热、力学和几何性能。本文对石墨烯及其衍生物、多孔炭片、炭布材料等二维碳质材料的制备进行了综述,并且概述了二维碳质材料在污染物吸附、检测和传感、锂离子电池、电容器、催化等领域中的应用,讨论了其发展中的挑战和展望。     

C/C复合材料层间裂纹扩展研究

作为一种耐高温高性能复合材料,Ｃ／Ｃ复合材料具优异的高温力学性能,但是材料本身的脆性是其弱点之一,其中,对于二维碳碳复合材料而言,层间裂纹扩展是其主要损伤机理,本文针对Ⅰ型和Ⅱ型层间裂纹扩展进行实验研究,深入分析了不同密度及加入填充剂填充的二维碳／碳复合材料的层间裂纹扩展方式,测试了Ⅰ型和Ⅱ型层间裂纹扩展能,发现裂纹扩展能随密度的增大而增大,加入石墨粉或热解炭粉可以有效提高材料的裂纹扩展能．     

Graphene: Piecing it together

Graphene has a multitude of striking properties that make it an exceedingly attractive material for various applications, many of which will emerge over the next decade. However, one of the most promising applications lie in exploiting its peculiar electronic properties which are governed by its electrons obeying a linear dispersion relation. This leads to the observation of half integer quantum hall effect and the absence of localization. The latter is attractive for graphene-based field effect transistors. However, if graphene is to be the material for future electronics, then significant hurdles need to be surmounted, namely, it needs to be mass produced in an economically viable manner and be of high crystalline quality with no or virtually no defects or grains boundaries. Moreover, it will need to be processable with atomic precision. Hence, the future of graphene as a material for electronic based devices will depend heavily on our ability to piece graphene together as a single crystal and define its edges with atomic precision. In this progress report, the properties of graphene that make it so attractive as a material for electronics is introduced to the reader. The focus then centers on current synthesis strategies for graphene and their weaknesses in terms of electronics applications are highlighted.     

石墨烯外延生长及其器件应用研究进展

石墨烯具有优异的物理和电学性能, 已成为物理和半导体电子研究领域的国际前沿和热点之一. 本文简单介绍了石墨烯的物理及电学特性, 详细评述了在众多制备方法中最有希望实现石墨烯大面积、高质量的外延生长技术, 系统论述了不同SiC和金属衬底外延生长石墨烯的研究进展, 并简要概述了石墨烯在场效应晶体管、发光二极管、超级电容器及锂离子电池等光电器件方面的最新研究进展. 外延生长法已经初步实现了从纳米、微米、厘米量级石墨烯的成功制备, 同时可实现其厚度从单层、双层到少数层的调控, 有望成为高质量、与传统电子工艺兼容、低成本、大面积的石墨烯宏量制备技术, 为其器件应用奠定基础.     

Converting graphene oxide monolayers into boron carbonitride nanosheets by substitutional doping

To realize graphene-based electronics, bandgap opening of graphene has become one of the most important issues that urgently need to be addressed. Recent theoretical and experimental studies show that intentional doping of graphene with boron and nitrogen atoms is a promising route to open the bandgap, and the doped graphene might exhibit properties complementary to those of graphene and hexagonal boron nitride (h-BN), largely extending the applications of these materials in the areas of electronics and optics. This work demonstrates the conversion of graphene oxide nanosheets into boron carbonitride (BCN) nanosheets by reacting them with B(2) O(3) and ammonia at 900 to 1100 °C, by which the boron and nitrogen atoms are incorporated into the graphene lattice in randomly distributed BN nanodomains. The content of BN in BN-doped graphene nanosheets can be tuned by changing the reaction temperature, which in turn affects the optical bandgap of these nanosheets. Electrical measurements show that the BN-doped graphene nanosheet exhibits an ambipolar semiconductor behavior and the electrical bandgap is estimated to be ≈25.8 meV. This study provides a novel and simple route to synthesize BN-doped graphene nanosheets that may be useful for various optoelectronic applications.     

Flexible,Stretchable, and Transparent Planar Microsupercapacitors Based on 3D Porous Laser‐Induced Graphene

The graphene with 3D porous network structure is directly laser‐induced on polyimide sheets at room temperature in ambient environment by an inexpensive and one‐step method, then transferred to silicon rubber substrate to obtain highly stretchable, transparent, and flexible electrode of the all‐solid‐state planar microsupercapacitors. The electrochemical capacitance properties of the graphene electrodes are further enhanced by nitrogen doping and with conductive poly(3,4‐ethylenedioxythiophene) coating. With excellent flexibility, stretchability, and capacitance properties, the planar microsupercapacitors present a great potential in fashionable and comfortable designs for wearable electronics.     

Nanoenvelopes: Wrapping a Single‐Walled Carbon Nanotube with Graphene using an Atomic Force Microscope

Engineering the morphology and structure of low‐dimensional carbon nanomaterials is important to study their mechanical and electrical properties and even superconductivity. Herein, first the techniques that are used to engineer carbon nanotubes, including manipulation, morphology modification, and fabrication of complex nanostructures, are reviewed. This is followed by a summary of the methods applied to fabricate graphene nanostructures, such as heterostructures and nanoenvelopes of graphene. Lastly, an insight into the applications of low‐dimensional‐carbon‐based electronics is given, such as carbon nanotube (CNT) transistors, graphene‐based nanoenvelopes, and graphene‐contacted CNT field‐effect transistors (FETs), which are promising components in future electronics.     

Flexible gigahertz transistors derived from solution-based single-layer graphene

Flexible electronics mostly relies on organic semiconductors but the limited carrier velocity in polymers and molecular films prevents their use at frequencies above a few megahertz. Conversely, the high potential of graphene for high-frequency electronics on rigid substrates was recently demonstrated. We conducted the first study of solution-based graphene transistors at gigahertz frequencies, and we show that solution-based single-layer graphene ideally combines the required properties to achieve high speed flexible electronics on plastic substrates. Our graphene flexible transistors have current gain cutoff frequencies of 2.2 GHz and power gain cutoff frequencies of 550 MHz. Radio frequency measurements directly performed on bent samples show remarkable mechanical stability of these devices and demonstrate the advantages of solution-based graphene field-effect transistors over other types of flexible transistors based on organic materials.     

电弧放电法制备石墨烯及其在导电油墨中的应用

导电油墨是印刷电子技术中使用的关键电子材料, 而导电填料作为导电油墨的主要成分要求其化学性能稳定且电导率高。其中, 基于石墨烯的导电油墨因为其、透射电子显微镜、拉曼光谱等手段对制备的石墨烯进行了表征。结果表明: 直流电弧放电法制备的石墨烯为2~10层、尺寸在100~200 nm范围且纯度高、结晶性好。在此基础上, 研究了涂层厚度、热处理温度以及弯曲角度等对石墨烯导电油墨导电性能的影响。研究发现, 石墨烯导电油墨电阻率与涂层厚度、热处理温度成反比, 且随着厚度、温度的增加石墨烯导电油墨的电阻率逐渐降低。并且样品在柔性基底上经过不同角度的弯曲折叠后电阻率没有明显变化。当厚度为170 μm的样品经过360℃ (30 min) 热处理后, 石墨烯导电油墨的电阻率仅为0.003 Ω·cm。上述结果表明, 电弧法制备的石墨烯导电油墨有望成为未来印制电子领域的关键材料。     

Structure and electronic transport in graphene wrinkles

Wrinkling is a ubiquitous phenomenon in two-dimensional membranes. In particular, in the large-scale growth of graphene on metallic substrates, high densities of wrinkles are commonly observed. Despite their prevalence and potential impact on large-scale graphene electronics, relatively little is known about their structural morphology and electronic properties. Surveying the graphene landscape using atomic force microscopy, we found that wrinkles reach a certain maximum height before folding over. Calculations of the energetics explain the morphological transition and indicate that the tall ripples are collapsed into narrow standing wrinkles by van der Waals forces, analogous to large-diameter nanotubes. Quantum transport calculations show that conductance through these "collapsed wrinkle" structures is limited mainly by a density-of-states bottleneck and by interlayer tunneling across the collapsed bilayer region. Also through systematic measurements across large numbers of devices with wide "folded wrinkles", we find a distinct anisotropy in their electrical resistivity, consistent with our transport simulations. These results highlight the coupling between morphology and electronic properties, which has important practical implications for large-scale high-speed graphene electronics.     

石墨烯透明导电薄膜可控制备及实用性研究

新型二维材料石墨烯,因其优异特性被认为是众多领域的理想新型功能材料,其产业化应用是当前及未来的重要研究课题之一。综述了针对性提高石墨烯导电薄膜透光率和导电性能的可控制备的最新研究进展,包括可控制备大尺寸、大面积石墨烯,以及通过掺杂或与其他材料形成复合材料等方法有效提高石墨烯薄膜的光电性能,并对石墨烯透明导电薄膜电极在触摸屏、显示屏等的实用化应用进行了探讨和展望。     

Graphene Oxide: Surface Activity and Two‐Dimensional Assembly

Graphene oxide (GO) is a promising precursor for preparing graphene‐based composites and electronics applications. Like graphene, GO is essentially one‐atom thick but can be as wide as tens of micrometers, resulting in a unique type of material building block, characterized by two very different length scales. Due to this highly anisotropic structure, the collective material properties are highly dependent on how these sheets are assembled. Therefore, understanding and controlling the assembly behavior of GO has become an important subject of research. In this Research News article the surface activity of GO and how it can be employed to create two‐dimensional assemblies over large areas is discussed.