石墨烯/半导体复合结构在光催化方面的应用研究进展

首先简单介绍了石墨烯的结构、性能和制备方法,然后着重阐述了石墨烯/半导体复合结构在光解水产氢、降解污染物、转化CO2这3个光催化方面的应用研究。最后从半导体的选择、复合工艺的改进、石墨烯功能化3个角度对研究过程中存在的问题提出了展望。     

石墨烯及石墨烯基复合柔性透明电极的研制

采用改进的化学气相沉积法制备了缺陷较少的石墨烯,并以旋涂导电聚合物薄膜为石墨烯中间基底,进行石墨烯薄膜的转移和柔性透明复合电极的制备。采用激光拉曼光谱、光学显微镜、动静态接触角仪、原子力显微镜、四探针测试仪和透光率仪等对制备的材料进行表征。分析了甲烷通入方式和石墨烯转移对石墨烯质量的影响,以及表面活性剂、旋涂转速对电极表面形貌及光学与电学性能的影响。结果表明:本实验环境下,使用的甲烷流量范围能制备出单层或少层的石墨烯,而先低后高式梯度浓度通入甲烷有利于减少石墨烯的缺陷,其ID/IG值最小,为0.034。双离子型表面活性剂改善了导电聚合物在石墨烯表面成膜的形貌,其表面粗糙度在8 nm左右,且表面活性剂浓度为10 mmol/L时,其在石墨烯表面的静态接触角为37.17°。选取最佳成膜导电聚合物水溶液配比,并在500 r/min旋涂转速下,所得复合电极的方阻为274.8Ω/sq,相比石墨烯降低了39.77%;当复合旋涂转速大于1 500 r/min时,复合电极透过率大于90%。     

石墨烯基超级电容器电极材料研究进展

石墨烯基纳米复合材料是制备超级电容器电极的重要原料之一,也是当下的研究热点。首先介绍了石墨烯/导电聚合物、石墨烯/金属氧化物两类二元纳米复合材料的特点及其制备方法;再介绍了三种不同结构类型的石墨烯/导电聚合物/金属氧化物三元纳米复合材料,并通过分析其结构特点,说明其优势与不足;最后简要介绍了石墨烯与金属硫化物、贵金属粒子以及其他碳材料复合的研究现状。通过分析可知,目前石墨烯基纳米复合材料仍存在较多不足之处,寻求快速、绿色、经济的方法制备能有效提高超级电容器电化学性能的石墨烯基纳米复合材料,将是未来的发展方向。     

石墨烯基复合吸波材料的研究进展

石墨烯由于其独特的物理和化学性能,在吸波领域备受瞩目,成为吸波材料研究的一大热点。综述了石墨烯／磁性纳米颗粒复合吸波材料、石墨烯／导电聚合物复合吸波材料及石墨烯／纳米金属或金属氧（硫）化物复合吸波材料在吸波领域的应用研究现状,并展望了石墨烯基复合吸波材料未来的发展方向。     

石墨烯基复合超级电容器材料研究进展

石墨烯基复合材料因其优异的性能广泛应用于各个领域,尤其在超级电容器的研究中。本文对石墨烯基复合超级电容器材料的结构进行了分类,并分别从石墨烯-碳基复合材料、石墨烯-导电高分子复合材料、石墨烯-过渡金属化合物复合材料的角度,总结了不同石墨烯基复合超级电容器材料的研究进展,重点强调了优化电极结构和提高电极性能之间的关系。同时,概述了石墨烯基复合材料在锂离子电池、太阳能电池、催化等其他方面的应用。获得高能量密度、功率密度以及长循环寿命的超级电容器是其作为电极材料的发展趋势。     

基于3D打印的三维石墨烯基电极研究进展

超级电容器是一种高性能的能量存储设备,因具有高功率密度、快速的充放电速率、高安全性能、优异的循环稳定性和较宽的工作温度范围等优点备受人们关注和青睐,并在清洁能源、电动汽车、无线通信、航空航天、军事和消费电子等领域得到了广泛的应用。电极材料是决定超级电容器储能性能的关键因素之一,开发新型、高效电极材料的已成为国内外研究的热点。传统电极材料经过长期的发展虽取得了一些技术革新和突破,但仍存在碳基电极容量不大、过渡金属化合物导电性不高、导电聚合物循环稳定性不足等缺点。石墨烯是一种由单层碳原子构成的碳纳米材料,具有优异的物理化学性能,是超级电容器电极材料的新宠。三维石墨烯不仅能保留单层或少数层石墨烯独特的物理化学性质,而且具有低密度、多孔性、高度连通结构和微反应环境等特性,在超级电容器领域备受关注,比石墨烯具有更加广泛的应用前景。目前,三维石墨烯的制备方法主要有湿化学技术、CVD技术和3D打印技术等。其中,3D打印技术凭借其在空间构型设计和化学组成优化方面的独特优势,在生物医药和能源器件等领域迅速发展。基于3D打印的石墨烯基材料不仅具有良好的孔道分布和优异的力学性能,而且其独特的3D打印结构还能...     

石墨烯基导热薄膜的研究进展

随着现代技术的发展,散热和导热已成为制约芯片器件小型化和大功率制造业发展的关键问题之一。由于传统的金属导热材料存在密度大和易氧化等问题,近年来以石墨烯基材料为代表的非金属碳基材料逐渐成为国内外的研究热点。本文综述了近年国内外石墨烯导热薄膜的制备方法及最新研究成果,分析讨论了热处理工艺、晶粒尺寸、薄膜密度及杂质原子和缺陷等对石墨烯导热薄膜性能的影响和物理机理,并对该领域的发展趋势进行了展望。     

石墨烯基复合材料的研究进展

主要概述了石墨烯基功能性复合材料的研究进展,着重介绍石墨烯与聚合物、其他碳质材料、金属纳米粒子以及金属化合物纳米粒子组成的石墨烯基复合材料的研究进展及其应用前景。     

Emergent properties resulting from type-II band alignment in semiconductor nanoheterostructures

The development of elegant synthetic methodologies for the preparation of monocomponent nanocrystalline particles has opened many possibilities for the preparation of heterostructured semiconductor nanostructures. Each of the integrated nanodomains is characterized by its individual physical properties, surface chemistry, and morphology, yet, these multicomponent hybrid particles present ideal systems for the investigation of the synergetic properties that arise from the material combination in a non-additive fashion. Of particular interest are type-II heterostructures, where the relative band alignment of their constituent semiconductor materials promotes a spatial separation of the electron and hole following photoexcitation, a highly desirable property for photovoltaic applications. This article highlights recent progress in both synthetic strategies, which allow for material and architectural modulation of novel nanoheterostructures, as well as the experimental work that provides insight into the photophysical properties of type-II heterostructures. The effects of external factors, such as electric fields, temperature, and solvent are explored in conjunction with exciton and multiexciton dynamics and charge transfer processes typical for type-II semiconductor heterostructures.     

光解水制氢半导体光催化材料的研究进展

自从Fujishima-Honda效应发现以来,科学研究者一直努力试图利用半导体光催化剂光分解水来获得既可储存而又清洁的化学能--氢能.近一二十年来,光催化材料的研究经历了从简单氧化物、复合氧化物、层状化合物到能响应可见光的光催化材料.本文重点描述了这些光催化材料的结构和光催化特性,阐述了该课题的意义和今后的研究方向.     

半导体电学特性四探针测试技术的研究现状

四探针法是材料学及半导体行业电学表征较常用的方法,其原理简单,能消除接触电阻影响,具有较高的测试精度.由厚块原理和薄层原理推导出计算公式,并经厚度、边缘效应和测试温度的修正即可得到精确测量值.据测试结构不同,四探针法可分为直线形、方形、范德堡和改进四探针法,其中直线四探针法最为常用,方形四探针多用于微区电阻测量.本文综述了四探针测试技术的基本理论,包括四探针法的分类、原理和修正,并阐述了四探针测试技术在微观领域的发展.     

The development of graphene-based devices for cell biology research

Graphene has emerged as a new carbon nanoform with great potential in many applications due to its exceptional physical and chemical properties. Especially, graphene and its derivatives are also gaining a lot of interest in the biomedical field as new components for biosensors, tissue engineering, and drug delivery. This review presents unique properties of graphene, the bio-effects of graphene and its derivatives, especially their interactions with cells and the development of graphene-based biosensors and nanomedicines for cancer diagnosis and treatment.     

Charge transport in disordered graphene-based low dimensional materials

Two-dimensional graphene, carbon nanotubes, and graphene nanoribbons represent a novel class of low dimensional materials that could serve as building blocks for future carbon-based nanoelectronics. Although these systems share a similar underlying electronic structure, whose exact details depend on confinement effects, crucial differences emerge when disorder comes into play. In this review, we consider the transport properties of these materials, with particular emphasis on the case of graphene nanoribbons. After summarizing the electronic and transport properties of defect-free systems, we focus on the effects of a model disorder potential (Anderson-type), and illustrate how transport properties are sensitive to the underlying symmetry. We provide analytical expressions for the elastic mean free path of carbon nanotubes and graphene nanoribbons, and discuss the onset of weak and strong localization regimes, which are genuinely dependent on the transport dimensionality. We also consider the effects of edge disorder and roughness for graphene nanoribbons in relation to their armchair or zigzag orientation. This article is published with open access at Springerlink.com     

An overview of the applications of graphene-based materials in supercapacitors

Due to their unique 2D structure and outstanding intrinsic physical properties, such as extraordinarily high electrical conductivity and large surface area, graphene-based materials exhibit great potential for application in supercapacitors. In this review, the progress made so far for their applications in supercapacitors is reviewed, including electrochemical double-layer capacitors, pseudo-capacitors, and asymmetric supercapacitors. Compared with traditional electrode materials, graphene-based materials show some novel characteristics and mechanisms in the process of energy storage and release. Several key issues for improving the structure of graphene-based materials and for achieving better capacitor performance, along with the current outlook for the field, are also discussed.     

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。     

Tunable graphene-based Q-switched erbium-doped fiber laser using fiber Bragg grating

A graphene-based Q-switched erbium-doped fiber laser (EDFL) with a tunable fiber Bragg grating (TFBG) acting as a wavelength tuning mechanism is proposed and demonstrated. The proposed setup utilizes a newly-developed ‘ferrule-to-ferrule transfer’ technique to obtain a single graphene layer that allows for Q-switch operation in the EDFL using a highly doped-gain medium. A TFBG is used as a wavelength tuning mechanism with a tuning range of 10 nm, covering the wavelength range from 1547.66 nm to 1557.66 nm. The system has a wide repetition rate range of over 206.613 kHz from 1.387 kHz to 208.000 kHz with pulse durations of between 94.80 μs to 0.412 μs. The laser output is dependent on the pump power, with energy per pulse of 4.56 nJ to 16.26 nJ. The system is stable, with power and wavelength variations of less than 0.47 dBm and 0.067 nm. The output pulse train is free from self-mode locking and pulse jitters.     

复合电沉积制备SnO2/TiO2薄膜及其光电催化性能

为了寻求廉价、高效和稳定的光催化剂,用复合电沉积技术在紫铜片上制备了Sn/TiO2薄膜,经300℃热氧化使之形成SnO2/TiO2复合电极.利用SEM,XRD对薄膜进行了表征,以甲基橙为模型化合物,对复合电极的光催化和光电催化性能进行了测定.研究表明:该薄膜由0.3~1μm的颗粒构成,每个颗粒又由纳米晶粒形成;电极具有多孔结构,膜中的SnO2以两种不同的晶体结构存在;在薄膜质量相等的情况下,SnO2/TiO2薄膜的光催化活性是纯TiO2粒子膜的2.87倍;外加一定偏压下,其催化性能大幅度提高.