功能氧化石墨烯纳米带/热塑性聚氨酯复合材料薄膜的制备及阻隔性能

以氧化解压多壁碳纳米管的方法制备了氧化石墨烯纳米带(GONRs),然后用异氟尔酮二异氰酸酯(IPDI)对GONRs化学修饰得到功能氧化石墨烯纳米带。采用溶液成形的方法在涂膜机上制备了功能氧化石墨烯纳米带(IPGONRs)/热塑性聚氨酯(TPU)复合材料薄膜,研究了IP-GONRs对TPU薄膜阻隔性能的影响。扫描电镜和X射线衍射的数据表明,IP-GONRs完全剥离地均匀分散在TPU基体中,并且基本沿着纳米复合材料薄膜表面平行分布。仅添加3.0%(质量分数,下同)的IP-GONRs时,TPU薄膜的氧气透过率便下降67%,因此获得了具有优异阻隔性能的IPGONRs/TPU纳米复合材料薄膜。这种具有优异阻隔性能的复合材料薄膜在食品包装和轻量气体存储容器方面有潜在的应用。     

氧化石墨烯纳米带与氧化石墨烯增强热塑性聚氨酯薄膜的制备及性能

利用纵向裂解多壁碳纳米管制备了氧化石墨烯纳米带,并采用溶液成型的方法制得氧化石墨烯纳米带-氧化石墨烯(GONRs-GO)/热塑性聚氨酯(TPU)复合材料薄膜。场发射扫描电镜和X射线衍射分析结果显示,GONRs与GO间相互剥离并均匀地分散在TPU基体中;氧气透过率(OTR)和力学性能测试表明,GONRs和GO具有协同增强TPU复合材料薄膜的阻隔和力学性能的作用。当GONRs和GO在TPU中添加量均为1.5%(质量分数)时,GONRs-GO/TPU复合材料薄膜的阻隔和力学性能达到最佳。相比于纯TPU薄膜,该GONRs-GO/TPU复合材料薄膜的OTR降低了83.94%,拉伸断裂强度、屈服强度、扯断伸长率则分别提高了59.28%,59.54%和15.0%。     

石墨烯纳米带的研究进展

自2010年石墨烯的发现者获得诺贝尔物理奖以来,石墨烯纳米带以其更好的理化性质成为了世界各国学者的研究热点。本文首先介绍了石墨烯纳米带的制备方法:切割碳纳米管法(电极切割碳纳米管法、混酸切割碳纳米管法、钾气裂解碳纳米管法、等离子体刻蚀碳纳米管法)、刻蚀石墨烯法(等离子体刻蚀石墨烯法、半月板掩模光刻石墨烯法、二维胶体晶体刻蚀石墨烯法)、膨胀石墨带减薄法、有机合成法、化学气相沉积法;然后介绍了石墨烯纳米带在电学领域的应用,还简要介绍了其在力学、热学等领域的应用;最后展望了石墨烯纳米带的发展前景。     

功能化氧化石墨烯纳米带/EVA复合材料薄膜的制备及表征

采用纵向氧化切割多壁碳纳米管法制得氧化石墨烯纳米带(GONRs),通过硅烷偶联剂KH-570与GONRs反应得到功能化氧化石墨烯纳米带,随后利用溶液成型的方法在涂膜机上制得功能化氧化石墨烯纳米带(K-GONRs)/乙烯-乙酸乙烯共聚物(EVA)复合材料薄膜.用FTIR,XRD,XPS,TEM,FE-SEM,氧气透过仪和电子万能试验机研究了复合材料的结构与性能.研究表明,本实验成功制得薄条状K-GONRs,其层间距约为0.970nm,相比GONRs增加了0.095nm; K-GONRs形状均一、规整并均匀分散于EVA基体中;当K-GONRs质量分数为1％时,K-GONRs/EVA复合材料薄膜的氧气透过率和拉伸强度相比纯EVA薄膜分别降低了54.5％和提高了89.3％,阻隔性能和力学性能得到明显改善.     

氧化石墨烯纳米带/TPU复合材料薄膜制备及性能表征

采用氧化法将碳纳米管纵向切割成氧化石墨烯纳米带,利用溶液成形在涂膜机上制备氧化石墨烯纳米带/TPU复合材料薄膜。FT-IR、拉曼光谱、XRD、FE-SEM、TEM等测试表明,碳纳米管成功地被纵向切割成带状结构的氧化石墨烯纳米带。力学测试表明,当氧化石墨烯纳米带用量为2%(质量分数)时,复合材料薄膜弹性模量与拉伸强度相比TPU薄膜提高了160%与123%。氧气透过率测试表明当氧化石墨烯纳米带用量为2%(质量分数)时,复合材料薄膜氧气透过率降低77%,阻隔性能明显提高。     

石墨烯纳米复合材料在电子转移及光电转换中的应用研究

石墨烯及其衍生物作为二维碳纳米材料可以有效地结合金属、半导体纳米粒子,同时,石墨烯及其衍生物与有机功能分子之间也可以通过共价或以π-π、静电等非共价形式发生相互作用。简述了石墨烯纳米复合材料的基本结构、制备策略、电子储存与转移以及能量传递特性,讨论了石墨烯纳米复合材料在光、电催化、电化学太阳能电池等领域中的研究应用进展。     

3D氧化石墨烯纳米带-碳纳米管/TPU复合材料薄膜的制备与性能

利用溶液成型法制得3D功能化氧化石墨烯纳米带-碳纳米管(pGONRs-CNTs)/热塑性聚氨酯(TPU)复合材料薄膜。采用FTIR,XRD,XPS和TEM对所得pGONRs-CNTs的结构及性能进行表征,并结合所得TPU复合材料薄膜的氧气透过率和拉伸性能测试以及表面形貌观察,研究GONRs与CNTs的协同作用以及不同含量pGONRs-CNTs对TPU复合材料薄膜阻隔和力学性能的影响。结果表明:pGONRs-CNTs复合体具有独特的3D交织状结构,其中GONRs间通过CNTs链接,二者间较强的π-π键使得这种结合形态牢固紧密,同时CNTs的存在也起到支撑骨架的作用,防止GONRs的滑移与团聚;通过异氰酸苯酯的改性处理,pGONRs-CNTs复合体的亲油性得到明显提高,同时较为庞大的异氰酸根的引入,使得GONR-GONR间的层间距得到了进一步的提高,更有利于其在聚合物基体中实现均匀分散。当pGONRs-CNTs质量分数为0.5%时,pGONRs-CNTs/TPU复合材料薄膜的氧气透过率和拉伸强度相比纯TPU薄膜分别降低了63.08%和提高了46.55%,阻隔性能和力学性能均得到显著改善。     

石墨烯制备与带隙调控的研究进展

石墨烯的独特结构和性能使其在纳米电子、半导体器件等领域中的研究成为热点课题。综述了石墨烯的结构特性及制备方法,重点评述了石墨烯带隙调控的方法及其原理,概括了各种方法可实现的带隙调节范围及研究现状,并介绍了半导体石墨烯在纳米电子器件上的应用前景,提出今后值得关注的研究方向。     

还原氧化石墨烯-贵金属纳米复合物的制备及表征

以氧化石墨和氯铂酸为前驱体,在油胺中简便地合成了还原氧化石墨烯-铂(Reduced graphene oxide-platinum,rGOPt)纳米复合物,并对其进行了表征。透射电子显微镜和光谱测试结果表明,铂纳米颗粒均匀分布在石墨烯表面,尺寸约为30nm,铂纳米粒子为多孔隙结构,结晶性能良好,氧化石墨在高温下转变为还原氧化石墨烯。用此方法也可以制备还原氧化石墨烯-金(rGO-Au)或还原氧化石墨烯-银(rGO-Ag)的纳米复合物,金、银纳米颗粒呈球状,对可见光具有明显的表面等离子吸收。同时,油胺作为溶剂、贵金属盐的还原剂和表面活性剂,使制备过程简单、快捷。     

石墨烯/聚合物纳米复合材料的研究进展

石墨烯与聚合物复合得到的纳米复合材料是具有广阔应用前景的新型材料。介绍了石墨烯的独特结构、性能和制备方法;着重论述了石墨烯/聚合物纳米复合材料的主要制备方法和表征技术,以及这些方法制备出的纳米复合材料在超级电容器、纳米电子器件、储存信息和通信材料等领域的广泛应用。同时也简述了其在现阶段研究中存在的一些问题,指出随着研究的不断深入,石墨烯/聚合物纳米复合材料的应用会逐渐广阔。     

Modified Engineering of Graphene Nanoribbons Prepared via On-Surface Synthesis

1D graphene nanoribbons (GNRs) have a bright future in the fabrication of next-generation nanodevices because of their nontrivial electronic properties and tunable bandgaps. To promote the application of GNRs, preparation strategies of miscellaneous GNRs have to be developed. The GNRs prepared by top-down approaches are accompanied by uncontrolled edges and structures. In order to overcome the difficulties, bottom-up methods are widely used in the growth of various GNRs due to controllability of GNRs' features. Among those bottom-up methods, the on-surface synthesis is a promising approach to prepare GNRs with distinct widths, edge/backbone structures, and so forth. Therefore, modified engineering of the GNRs prepared via on-surface synthesis is of great significance in controllable preparation of GNRs and their potential applications. In the past decade, there have been a lot of reports on controllable preparation of GNRs using on-surface synthesis approach. Herein, the advances of GNRs grown via on-surface growth strategy are described. Several growth parameters, the latest advances in the modification of the GNR structure and width, the GNR doping/co-doping with heteroatoms, a variety of GNR heterojunctions, and the device application of GNRs are reviewed. Finally, the opportunities and challenges are discussed.     

Graphene Nanoribbons: On-Surface Synthesis and Integration into Electronic Devices

Graphene nanoribbons (GNRs) are quasi-1D graphene strips, which have attracted attention as a novel class of semiconducting materials for various applications in electronics and optoelectronics. GNRs exhibit unique electronic and optical properties, which sensitively depend on their chemical structures, especially the width and edge configuration. Therefore, precision synthesis of GNRs with chemically defined structures is crucial for their fundamental studies as well as device applications. In contrast to top-down methods, bottom-up chemical synthesis using tailor-made molecular precursors can achieve atomically precise GNRs. Here, the synthesis of GNRs on metal surfaces under ultrahigh vacuum (UHV) and chemical vapor deposition (CVD) conditions is the main focus, and the recent progress in the field is summarized. The UHV method leads to successful unambiguous visualization of atomically precise structures of various GNRs with different edge configurations. The CVD protocol, in contrast, achieves simpler and industry-viable fabrication of GNRs, allowing for the scale up and efficient integration of the as-grown GNRs into devices. The recent updates in device studies are also addressed using GNRs synthesized by both the UHV method and CVD, mainly for transistor applications. Furthermore, views on the next steps and challenges in the field of on-surface synthesized GNRs are provided.     

Electronic Property Modification of Single‐Walled Carbon Nanotubes by Encapsulation of Sulfur‐Terminated Graphene Nanoribbons

The use of carbon nanotubes (CNTs) as cylindrical reactor vessels has become a viable means for synthesizing graphene nanoribbons (GNRs). While previous studies demonstrated that the size and edge structure of the as‐produced GNRs are strongly dependent on the diameter of the tubes and the nature of the precursor, the atomic interactions between GNRs and surrounding CNTs and their effect on the electronic properties of the overall system are not well understood. Here, it is shown that the functional terminations of the GNR edges can have a strong influence on the electronic structure of the system. Analysis of SWCNTs before and after the insertion of sulfur‐terminated GNRs suggests a metallization of the majority of semiconducting SWCNTs. This is indicated by changes in the radial breathing modes and the D and G band Raman features, as well as UV–vis–NIR absorption spectra. The variation in resonance conditions of the nanotubes following GNR insertion make direct (n,m) assignment by Raman spectroscopy difficult. Thus, density functional theory calculations of representative GNR/SWCNT systems are performed. The results confirm significant changes in the band structure, including the development of a metallic state in the semiconducting SWCNTs due to sulfur/tube interactions. The GNR‐induced metallization of semiconducting SWCNTs may offer a means of controlling the electronic properties of bulk CNT samples and eliminate the need for a physical separation of semiconducting and metallic tubes.     

Combined Visible Plasmons of Ag Nanoparticles and Infrared Plasmons of Graphene Nanoribbons for High-Performance Surface-Enhanced Raman and Infrared Spectroscopies

Ag nanoparticles (NPs) modified graphene nanoribbons (GNRs) are proposed to function as the high-performance shared substrates for surface-enhanced Raman and infrared absorption spectroscopy (SERS and SEIRAS). This is realized by modulating the localized plasmonic resonances of Ag NPs in visible region and GNRs in mid-infrared region simultaneously, so as to selectively employ each resonance to acquire SERS and SEIRAS on a single substrate. As a proof of concept, shared substrates are prepared by fabricating GNRs on a Fabry–Pérot like cavity, followed by depositing a thin Ag film with annealing treatment to achieve Ag NPs. Complementary Raman and infrared active vibrational modes of rhodamine 6G molecules can be extracted from the SERS and SEIRAS spectra. By optimizing the dimension of Ag NPs, SERS enhancement factors at the order of 10⁵ can be achieved, which are comparable with or even larger than that of the reported shared substrates. Meanwhile, various polyethylene oxide vibrational modes can be recognized with maximum SEIRAS amplification up to 170 times, which is one order larger than that of the reported graphene plasmonic infrared sensors. Such plasmonic nanosensor with excellent SERS and SEIRAS performance exhibits promising potential for biosensing applications on an integrated lab-on-a-chip strategy.     

Metallic Graphene Nanoribbons

Isolated graphene nanoribbons(GNRs)usually have energy gaps,which scale with their widths,owing to the lateral quantum confinement effect of GNRs.The absence of metallic GNRs limits their applications in device interconnects or being one-dimensional physics platform to research amazing properties based on metallicity.A recent study published in Science provided a novel method to produce metallic GNRs by inserting a symmetric superlattice into other semiconductive GNRs.This finding will broader the applications of GNRs both in nanoelectronics and fundamental science.     

Massive Dirac Fermion Behavior in a Low Bandgap Graphene Nanoribbon Near a Topological Phase Boundary

Graphene nanoribbons (GNRs) have attracted much interest due to their largely modifiable electronic properties. Manifestation of these properties requires atomically precise GNRs which can be achieved through a bottom–up synthesis approach. This has recently been applied to the synthesis of width-modulated GNRs hosting topological electronic quantum phases, with valence electronic properties that are well captured by the Su–Schrieffer–Heeger (SSH) model describing a 1D chain of interacting dimers. Here, ultralow bandgap GNRs with charge carriers behaving as massive Dirac fermions can be realized when their valence electrons represent an SSH chain close to the topological phase boundary, i.e., when the intra- and interdimer coupling become approximately equal. Such a system has been achieved via on-surface synthesis based on readily available pyrene-based precursors and the resulting GNRs are characterized by scanning probe methods. The pyrene-based GNRs (pGNRs) can be processed under ambient conditions and incorporated as the active material in a field effect transistor. A quasi-metallic transport behavior is observed at room temperature, whereas at low temperature, the pGNRs behave as quantum dots showing single-electron tunneling and Coulomb blockade. This study may enable the realization of devices based on carbon nanomaterials with exotic quantum properties.     

MOF-Derived In2O3/CuO p-n Heterojunction Photoanode Incorporating Graphene Nanoribbons for Solar Hydrogen Generation

Solar-driven photoelectrochemical (PEC) water splitting is a promising approach toward sustainable hydrogen (H₂) generation. However, the design and synthesis of efficient semiconductor photocatalysts via a facile method remains a significant challenge, especially p-n heterojunctions based on composite metal oxides. Herein, a MOF-on-MOF (metal-organic framework) template is employed as the precursor to synthesize In₂O₃/CuO p-n heterojunction composite. After incorporation of small amounts of graphene nanoribbons (GNRs), the optimized PEC devices exhibited a maximum current density of 1.51 mA cm⁻² (at 1.6 V vs RHE) under one sun illumination (AM 1.5G, 100 mW cm⁻²), which is approximately four times higher than that of the reference device based on only In₂O₃ photoanodes. The improvement in the performance of these hybrid anodes is attributed to the presence of a p-n heterojunction that enhances the separation efficiency of photogenerated electron-hole pairs and suppresses charge recombination, as well as the presence of GNRs that can increase the conductivity by offering better path for electron transport, thus reducing the charge transfer resistance. The proposed MOF-derived In₂O₃/CuO p-n heterojunction composite is used to demonstrate a high-performance PEC device for hydrogen generation.     

掺杂对锯齿形(Zigzag)石墨烯纳米带输运性质的影响

基于第一性原理计算,研究了掺杂对锯齿形石墨烯纳米带电子输运性质的影响。研究发现,掺杂原子种类、掺杂位置的不同将对电子输运产生极大的影响。当中间散射区域的中心C原子被B杂质原子代替时,在电子输运谱的费米能级以下会出现一个零透射的波谷,而另一侧则不变;当带中心杂质为N原子时情况正好相反。零透射波谷的出现意味着有带隙产生,即发生了从金属到半导体的转变。当杂质原子从中心位置移到带边缘时,波谷将移到费米能级的另一侧,从而引起从受主到施主特征的转变,这是杂质原子的束缚态与边缘态相互作用的结果。     

Advance in Close‐Edged Graphene Nanoribbon: Property Investigation and Structure Fabrication

The absence of dangling bonds in close‐edged graphene nanoribbons (CEGNRs) confers upon them a series of fascinating properties, especially when compared with cylindrical carbon nanotubes and open‐edged GNRs. Here, the configuration of CEGNRs is described, followed by the structure‐related properties, including mechanical, thermal, electrical, optical, and magnetic properties. Based on the unique structures and extraordinary properties, their potential applications in a variety of fields, such as field‐effect transistors, energy suppliers, nanoactuators, and fibers, are discussed. Remarkably, the strategies applied for generating CEGNRs, mainly from the collapse of carbon nanotubes and graphene tubes, are depicted in detail. Finally, the prospects in the research area of CEGNRs are proposed.     

电场作用下扶手椅型石墨烯纳米带的第一原理计算

本文采用密度泛函理论,研究了边缘氧化扶手椅型石墨烯纳米带(AGNRs)的电子结构和相对稳定性.结果表明,边缘氧化的AGNRs要比边缘氢化的纳米带稳定.由于氧原子比碳原子具有较大的电负性,边缘氧化AG-NRs表现出金属性能带结构.此外,氧饱和AGNRs比氢饱和AGNRs对电场作用更为敏感,这将有助于在带隙工程中实现其电子结构剪裁.