聚苯胺与还原石墨烯复合材料的微波吸收性能

采用化学氧化法制备聚苯胺与还原石墨烯复合材料。复合材料的结构、晶型和电磁参数分别通过X射线衍射仪及HP8722ES型矢量网络分析仪进行表征、测试与分析。结果表明,同聚苯胺相比,聚苯胺与还原石墨烯复合材料的介电损耗明显增加。而且在复合材料中,石墨烯的含量越大,材料的微波吸收性能越好,在频率波段（9.5~13.4GHz）反射损耗均小于-10 dB,并在频率为11.2 GHz时达到最大反射损耗-29.69 dB。聚苯胺与还原石墨烯的复合使得材料的载流子迁移率变大,吸波特性得到改善。     

氧化石墨烯-卟啉复合材料光限幅性能的理论研究

利用时域有限差分法数值求解速率-场强方程,研究了一系列共价连接的氧化石墨烯-卟啉复合材料在纳秒时域内的光限幅性质和双光子吸收. 计算结果表明,氧化石墨烯-卟啉复合分子与单独的卟啉分子相比展现出增强的光限幅效应,并且有着更大的双光子吸收截面.与之前得到的含重金属的卟啉分子具有更强非线性光学性质的结论不同,不含金属元素的卟啉分子与氧化石墨烯结合后展现出了更强的非线性光学性质. 理论计算的结果与实验测量符合较好. 此外,着重研究了介质的厚度和脉冲宽度对分子双光子吸收截面的影响. 结果表明,随着介质厚度的增加或者脉宽的变宽分子的动态双光子吸收截面增大.     

盐酸掺杂聚苯胺薄膜的隐身性能

将本征态聚苯胺的N-甲基吡咯烷酮溶液浇铸在玻璃基板上,烘干脱去基板后得到自支持本征态聚苯胺薄膜,用HCl气体对薄膜进行掺杂,通过控制掺杂时间来控制掺杂浓度.红外反射率测试结果表明:在大气窗口内,掺杂浓度较低时,薄膜的红外反射率随着掺杂浓度的提高而增加;到达一定掺杂浓度后,反射率会随着掺杂浓度的提高有所降低,最终趋于稳定...     

还原石墨烯氧化物-银纳米线柔性复合电极的制备与性能研究

制备了一种具有高导电性、高透过率以及良好的柔性和机械稳定性的还原石墨烯氧化物(RGO)-银纳米线(AgNW)复合电极.将低浓度的AgNW旋涂在制备的RGO薄膜上,使AgNW搭接在RGO的晶界、褶皱处,提高了RGO薄膜的载流子迁移能力.在保证透过率的前提下,提高复合薄膜的导电性能.结合薄膜转写工艺,制备了电阻为420 Ω/口且透过率达62％的RGO-AgNW柔性复合电极.该复合电极具有良好的柔性以及机械稳定性,随着弯折次数的增加,电阻没有明显变化.     

激光烧结石墨烯-铜纳米复合材料性能研究

石墨烯拥有许多优异的性能,这些性能使石墨烯有望成为金属基复合材料的理想增强相。采用激光烧结的方法制备了石墨烯-铜纳米复合材料。X射线衍射（XRD）和Raman光谱测试结果表明,石墨烯存在于激光烧结所制备的纳米复合材料中。显微硬度测试结果显示,石墨烯的添加使得石墨烯-铜纳米复合材料的硬度比激光烧结纯铜的硬度提高了约22%。用电化学极化法研究了激光烧结的石墨烯-铜纳米复合材料和纯铜在3.5%（质量分数）NaCl 溶液中的腐蚀行为,石墨烯-铜纳米复合材料的腐蚀电位比激光烧结纯铜的腐蚀电位略有降低,腐蚀电流也有所降低,说明其耐腐蚀性能较激光烧结纯铜略好。     

激光烧结石墨烯-铜纳米复合材料性能研究

石墨烯拥有许多优异的性能,这些性能使石墨烯有望成为金属基复合材料的理想增强相。采用激光烧结的方法制备了石墨烯-铜纳米复合材料。X射线衍射(XRD)和Raman光谱测试结果表明,石墨烯存在于激光烧结所制备的纳米复合材料中。显微硬度测试结果显示,石墨烯的添加使得石墨烯-铜纳米复合材料的硬度比激光烧结纯铜的硬度提高了约22%。用电化学极化法研究了激光烧结的石墨烯-铜纳米复合材料和纯铜在3.5%(质量分数)NaCl溶液中的腐蚀行为,石墨烯-铜纳米复合材料的腐蚀电位比激光烧结纯铜的腐蚀电位略有降低,腐蚀电流也有所降低,说明其耐腐蚀性能较激光烧结纯铜略好。     

单层与双层石墨烯的光学吸收性质研究

采用紧束缚模型分别描述单层、双层石墨烯的能带结构, 利用光子-电子相互作用的二阶微扰理论分别计算单光子和双光子吸收系数.计算结果表明: 单层石墨烯单光子吸收系数为常数, 约为6.8×10⁷ m^-1, 即单层石墨烯对入射光的吸收率约为2.3%; 双层石墨烯的单光子吸收比单层石墨烯的单光子吸收强, 且随入射光波长呈分段性变化.单层石墨烯的双光子吸收系数与波长λ⁴成正比; 双层石墨烯双光子吸收系数在红外波段(～ 3100 nm处)有一个很强的共振吸收峰. 研究结果可为石墨烯材料在光电子器件的研究和制作方面提供指导. 关键词： 石墨烯 光学吸收 紧束缚模型     

电化学法制备的还原氧化石墨烯薄膜及其光电性能研究

通过电化学方法在FTO导电玻璃上沉积了不同还原程度(C/O)的还原氧化石墨烯薄膜(rGO),其中rGO薄膜由未经处理的GO电解液制备,A-rGO由碱处理后的电解液制备,B-rGO由NaBH4处理后的电解液制备。利用XRD、XPS、SEM、UV-Vis对薄膜的化学结构和微观形貌进行了表征,并研究了薄膜在可见光照射下的光电性能。结果表明:在1.8 V下沉积的不同C/O比的rGO薄膜中,B-rGO薄膜的C/O比最高(8.1),带隙最小(0.54 eV),导带最靠近FTO的导带位置。在可见光照射下,几种薄膜均产生了阴极电流,电流密度随C/O比的增大而增大,其中B-rGO最大达1μA·cm-2。本文提供了一种通过控制C/O比来控制rGO薄膜光电性能的方法。     

ZnO/CoFe_2O_4复合材料的制备与吸波性能

采用水热法和化学共沉淀法分两步合成了ZnO/CoFe2O4复合体.吸波性能测试结果表明,ZnO/CoFe2O4复合体吸波性能有所提高.这主要归因于CoFe2O4和ZnO的复合,实现了阻抗匹配,充分利用了CoFe2O4铁氧体的磁损耗和ZnO材料的介电损耗,从而获得性能优越的吸波剂材料.     

石墨烯/钡铁氧体复合材料的制备及微波吸收性能的综合实验设计

电磁波污染已经严重威胁到信息安全和人体的健康,微波吸收材料被认为是解决电磁波污染问题最可行的措施之一。通过水热法获取氧化石墨烯/钡铁氧体纳米复合物,利用X-射线衍射仪、扫描电子显微镜、振动样品磁强计和矢量网络分析仪等分析技术对所制备的材料进行了表征。结果显示,当复合材料的厚度为2 mm时,其有效带宽可达6.8 GHz,当频率在12.64 GHz时,反射损耗最小为-41.66 dB。通过此综合实验设计,从实验的角度对纳米复合材料吸波机理进行了研究,有助于提高学生的科研兴趣,启发学生创新思维。     

Three Dimensional Branched Gold Nanostructures on Reduced Graphene Oxide Films Formed at a Liquid/Liquid Interface

Interfacing anisotropic gold nanostructures with graphene can open up new avenues for modifying the light–matter interaction of graphene. A chemical route is explored to synthesize branched gold nanostructures on reduced graphene oxide (rGO) layers by in situ reduction, assisted by binary surfactant mixtures containing tetraoctylammonium bromide with cetyltrimethy­lammonium bromide, sodium dodecylsulfate, or sodium citrate. The hybrid material self‐assembles at a liquid/liquid interface forming a free‐standing film. Electron microscopy studies reveal the morphology, microstructure, and crystallinity of the hybrids. The gold nanostructures are branched in three dimensions and possess various shapes, such as irregular stars, multipods, and spiky features, interspersed with rGO layers. The hybrids exhibit plasmon modes in the visible and near‐infrared region due to the shape anisotropy. The enhancement effect of the spiky features is also observed in the Raman spectra. The growth mechanism of the branched nanostructures is followed by kinetic studies and indicates that the formation of multiple twinned crystals is the key factor for branching.     

Development of Novel Graphene/g‐C3N4 Composite with Broad‐Frequency and Light‐Weight Features

In this study, a novel graphene/g‐C₃N₄ microwave absorber is developed to solve the electromagnetic wave interference problem. Graphene/g‐C₃N₄ composite is synthesized by loading g‐C₃N₄ nanosheets on graphene through a simple liquid‐phase approach. High‐performance electromagnetic absorption performance can be achieved. The optimal reflection loss value is up to ?29.6 dB under a thin coating layer of 1.5 mm. At the same time, the corresponding absorption bandwidth of this composite can reach 5.2 GHz (12.8–18 GHz). Excellent electromagnetic absorption property may be attributed to the current attenuation theory which has been proven by replacing graphene with porous graphene or graphene oxide. The results reveal that free electron numbers and loading mass of g‐C₃N₄ on graphene play the key roles in the intensity of current attenuation and resistance value.     

高温还原氧化石墨烯膜及其导热性能

采用氧化还原法制备了结构致密且具有较高柔韧性的石墨烯薄膜,探究了薄膜经过较高退火温度还原后结构变化,并通过T型稳态法测量了其热导率,研究了还原温度对薄膜热导率和力学性能的影响。结果表明,高温还原有助于氧化石墨烯中含氧官能团的去除和sp2杂化碳晶格的恢复,并且温度越高还原效果越好。当还原温度高达2800℃时,在200~350 K温度范围内石墨烯膜的热导率在336.9~436 W·m^-1·K^-1之间,伴随着温度的升高,热导率有先增大后减小的趋势。     

Graphene Nanosheets Suppress the Growth of Sb Nanoparticles in an Sb/C Nanocomposite to Achieve Fast Na Storage

Presently, graphene incorporation is one of the most effective strategies to develop superior electrode materials for sodium‐ion batteries (SIBs). Herein, it is excitingly found that an incorporated graphene nanosheet in the preparation processes can not only completely protect all the Sb nanoparticles in an Sb/C composite from being inactivated, but also suppresses their growth to undesirable micrometer size. While there are still many exposed Sb particulates on the surface of pristine Sb/C microplates, the graphene‐incorporated Sb/C/G nanocomposite consists of uniform Sb nanoparticles of 20–50 nm, all of which have been protected by and wrapped in the mixed carbon network. When used as anode materials for SIBs, the Sb/C/G nanocomposite exhibits the best Na‐storage properties in terms of the highest reversible capacity (650 mA h g^?1 at 0.025 A g^?1), fastest Na‐storage ability (290 mA h g^?1 at a high current density of 8 A g^?1), and optimal cycling performance (no capacity decay after 200 cycles), in comparison to pristine Sb/C and pure Sb. It is further revealed that the much enhanced performance should originate from the improvement of Na‐storage kinetics and increase of electronic conductivity via comparing the electrochemical impedance spectra, and cyclic voltammetry profiles, as well as the polarization variation along with current densities.     

氧化石墨烯/硒化锌纳米光电材料的制备及其蓝光发射特性

采用一种简单有效的原位水热合成方法,使用石墨烯氧化物（GO）作为反应物和晶体生长基底成功制备出了还原氧化石墨烯/硒化锌（r-GO/ZnSe）纳米复合材料。采用X射线粉末衍射（XRD）、透射电子显微镜（TEM）、高分辨透射电镜（HRTEM）以及红外-可见光谱（FT-IR）等方法对r-GO/ZnSe纳米复合材料进行了检测。结果表明,平均粒径在30 nm的立方闪锌矿晶体结构的ZnSe粒子均匀分散在氧化石墨烯片层上,构成纳米复合结构。 UV-Vis光谱显示,纳米复合材料的光学吸收的起始波长在445 nm附近。PL光谱显示,纳米复合材料在470 nm附近存在一个很强的发射峰。这种石墨烯基纳米复合材料在白光二极管领域中有重要的应用价值。     

Synergetic Photocatalytic Nanostructures Based on Au/TiO2/Reduced Graphene Oxide for Efficient Degradation of Organic Pollutants

Recently, there is crucial interest in the design and fabrication of nanocatalysts for efficient decomposition of organic pollutants in wastewater using visible light. This work reports the assembling fabrication of synergetic photocatalytic Au/TiO₂/RGO nanostructures by utilizing the reduced graphene oxide (RGO) as substrate material and efficient separator for electrons and holes. The Au/TiO₂ nanostructures with a ≈7 nm TiO₂ particles size are dispersed uniformly on RGO nanosheets. UV–vis diffuse reflectance spectroscopy verifies that Au/TiO₂/RGO nanocomposites show strong absorption of visible light. The degradation efficiency after 1 h for hydroquinone under visible light and UV light is ≈77% and ≈90%, respectively. Under visible light, the calculated apparent rates (k ) of the Au/TiO₂/RGO nanocomposites are 0.0112 and 0.0174 min^?1 for decomposition of methylene blue and hydroquinone. That are five times greater than that of bare TiO₂. The high photocatalytic activity is mainly attributed to the synergy between RGO and Au/TiO₂ nanostructure. The strategy of composite nanostructures assembling on RGO is ensured to have a great practicable potential for the designing of high efficient multielement composite nanoparticles catalysts.