石墨烯在电子器件研究中的应用

石墨烯是近年来逐步发展起来的新型电子材料,具有导电性好、电子迁移率高、比表面积大、导热率高、弹性好等优点,石墨烯的开发和应用已成为纳米材料、生物、化学以及电子信息等多个领域的研究热点。围绕近年来石墨烯在电子器件中的应用研究,本文主要对其在生化传感器、高速器件、太阳能电池、储能器件、柔性器件5个热点方向中的部分研究成果进行综述。     

石墨烯材料在电子器件中的应用

石墨烯材料在电子器件中的应用有着较好的兼容性,现阶段石墨烯材料得到人们和相关技术人员的高度认可,并且将其广泛应用于化学、生物、电子信息等多个领域。     

基于碳纳米管的电子器件

碳纳米管有着众多独特的性质 ,尤其是它的电学性质。近几年来 ,碳纳米管的研究已展示出了在纳米电子器件上的应用前景 ,即通过构建尺寸只有几十纳米甚至更小的基于碳纳米管的电子器件和连线 ,实现速度远快于而功耗远小于目前集成电路的碳纳米管集成电路。文中在讨论碳纳米管电学性质的基础上 ,主要介绍基于碳纳米管的结、场效应晶体管和单电子晶体管等最新研究和进展     

碳纳米管在典型微纳电子器件中的应用进展

优异的电学、热学、机械特性和化学稳定性以及独特的一维纳米结构,使碳纳米管(CNT)成为应用在微纳电子器件中的理想功能材料。与传统电子器件相比,CNT微纳电子器件性能更为优异。本文综述了近年来制备和改进基于CNT的场发射器、晶体管和传感器的研究进展。经过特定方法的组装和处理,可使CNT场发射器获得低阀值电压、高发射电流和发射电流稳定等优异性能,使CNT晶体管具有高迁移率、大跨导和大电流开闭比,可提高各种CNT传感器的灵敏度。

     

基于PDMS-石墨烯泡沫的柔性压力传感器

为了解决柔性压力传感器在大的工作范围内工作时难以兼顾灵敏度的问题,设计了一种基于聚二甲基硅氧烷(PDMS)锥形微结构且夹层为石墨烯泡沫的柔性压力传感器.介绍了该传感器的制备方法,对比了有无锥形微结构的PDMS基底对传感器灵敏度的影响,分别对它们进行了相关测试.结果表明,具有锥形微结构基底的传感器具有更高的灵敏度,基于锥...     

利用碳纳米管制成的柔性有机发光二极管

加拿大蒙特利尔大学开发出制作柔性有机发光二极管（OLED）的工艺方法,使制造出柔性显示屏成为可能,该技术还可用于生产发光服装。     

激光诱导碳纳米管制备石墨烯纳米带及其电学性能分析

通过将纳米管解压缩可以很容易地生产石墨烯纳米带,因为碳纳米管结构可以被认为是卷起的石墨烯筒。这是一种特殊的2D石墨结构,具有出色的性能。应用领域广泛,包括晶体管、光学和微波通信设备、生物传感器、化学传感器、电子存储和处理设备以及纳米机电系统和复合材料。通过扫描电子显微镜（SEM）观察薄膜的形貌,通过拉曼光谱法表征石墨烯的性质,并通过半导体参数测量系统测量薄膜的电导率。拉曼光谱表明,通过优化工艺可以增强石墨烯的拉曼特性。碳纳米管制备石墨烯带的两个重要参数是激光能量密度和辐照时间。在这项研究中,通过准分子激光辐照碳纳米管薄膜来生产石墨烯纳米带。实验结果表明,在150 mJ的激光能量下,观察到连接时碳纳米管没有打开。在450 mJ的能量下,可以有效地破坏碳纳米管,并且使其部分地形成石墨烯带。此时,膜的电导率达到最大值。由于蓄热作用,在碳纳米管壁上出现大量的多孔结构。     

石墨烯柔性透明导电薄膜的制备

采用液相剥离法,以石墨粉末为原料,在有机溶剂中直接超声剥离,通过高速离心后得到质量较高的石墨烯分散液。利用喷涂法,在柔性基底(PET)上制备石墨烯透明导电薄膜。借助SEM、四探针等表征方法,研究不同有机溶剂和不同基底处理对薄膜表面形貌和光电性能的影响。结果表明:使用DMF作为分散剂制备的石墨烯没有引入其他官能团,结构缺陷少;在基底上做一层银金属栅网,可以有效降低薄膜的方片电阻,在透过率(λ=550nm)为81%时,方块电阻降低为172Ω/□,这种新型石墨烯/银金属栅网柔性透明导电薄膜有望取代市场主流ITO薄膜。     

有机显示器和电子器件的柔性基板和封装

尽管柔性显示技术面临性能的挑战,第一款商业化的产品仍计划在2006-2007年度投入市场.     

Synthesis of blue light-emitting graphene quantum dots and their application in flexible nonvolatile memory

We presented a facile method to prepare graphene quantum dots (GQDs) from double-walled carbon nanotube with blue light emission in a chlorobenzene solution, which enabled the preparation of GQD–polymer hybrid nanocomposite. The wavelength-dependent fluorescent lifetime of the GQDs was investigated by using time-resolved photoluminescence technique. Significantly, nonvolatile rewritable memory effect was observed for the GQD-based nanocomposite, suggesting the promising applications of GQDs in data storage. Moreover, due to the easy solution process, we demonstrated the design and realization of flexible GQD-based memory device. This work may expand the application of GQDs to the portable electronic devices.     

Impact of adhesive rheology on stress-distortion of bonded plastic substrates for flexible electronics applications

For fabrication of flexible electronics using standard microelectronics toolsets, a temporary bond-debond method has been developed that requires minimization of the distortion of bonded flexible substrate and bow of bonded system (flexible substrate-adhesive-carrier) during processing. To elucidate the critical parameters of the adhesive used in the bonding that control the stress (bow) and distortion, adhesives with different viscoelastic properties are examined systematically. By blending a high modulus adhesive into a low modulus adhesive, the storage modulus, loss modulus and loss factor of the adhesive can be tuned by orders of magnitude. Detailed examination of the impact of these three rheological parameters on the stress and distortion of bonded system reveals that the relative viscoelastic flow properties of the bonding adhesive to that of the bonded flexible substrate are directly correlated to bow and distortion. When the loss factor of the adhesive is less than that for the plastic substrate, precise registration of layers during photolithography is observed. These results provide insight into the rheological parameters critical to the adhesive formulations for the temporary bond-debond method in the fabrication of flexible electronics.     

Integration of a graphene ink as gate electrode for printed organic complementary thin-film transistors

We demonstrate a new electrode gate based on graphene ink for complementary printed organic metal oxide semiconductor (CMOS) technology on flexible plastic substrates. The goal is to replace the standard silver electrode gate. Devices made with graphene were enhanced and showed a high field-effect mobility of 3 cm² V⁻¹ s⁻¹ for P-type and 0.9 cm² V⁻¹ s⁻¹ for the N-type semiconductors. The improvement is attributed to the increase of the electrical capacitance of the organic dielectric (CYTOP) due to the graphene layer. A seven-stage ring oscillator was made with high oscillation frequencies of 2.1 kHz at 40 V corresponding to a delay/gate value of 34 μs. These performances are promising for use of low cost printed electronic applications.     

应用于印制电子的纳米银材料

最近印制电子技术发展日益完善,这项技术在传统印制电路板行业中也展现出巨大的应用前景。本文着重介绍了应用于印制电子的银纳米材料的发展现状,从与传统PCB导线制备工艺的比较中说明打印法制备银导线及材料的优势。文中还讨论了用于印制电子的纳米银材料的制备、墨水的配制、打印工艺、应用前景。     

Fabrication of flexible conductive graphene/Ag/Al-doped zinc oxide multilayer films for application in flexible organic light-emitting diodes

Graphene/Ag/Al-doped zinc oxide (AZO) multilayer films were fabricated by using chemical vapor deposition and magnetron sputtering methods. The electrical and optical properties of the transparent conductive graphene/Ag/AZO films were investigated. The graphene/Ag/AZO film can maintain high conductivity and transmittance without obvious degradation during bending test. A green flexible organic light emitting diode with a structure of graphene/Ag/AZO/N,N-diphenyl-N,N-bis(1-napthyl)-1,1-biphenyl-4,4-diamine/tris(8-hydroxyquinoline) aluminum(III)/lithium fluoride/Al exhibited a stable green emission and light-emitting efficiency during the cycle bending test. The multilayer films hold promise for application in flexible optoelectronic devices.     

All-solution-processed foldable transparent electrodes of Ag nanowire mesh and metal matrix films for flexible electronics

In this study, we developed foldable transparent electrodes composed of Ag nanowire (AgNW) networks welded by Ag nanoparticles (AgNPs) reduced from commercial Ag ink. All the processes used were solution-based. Using the Meyer rod method, uniform AgNW networks were roll-to-roll coated on large-area polymer substrates, and the spin-coated AgNPs firmly welded the AgNWs together at junctions and to substrates. The hybrid films consisting of AgNWs and the Ag film matrix exhibited higher electrical conductivity (5.0–7.3 × 10⁵ S/m) than and equivalent transparency (90–95%) to the AgNW networks. Furthermore, the hybrid films showed significantly better bending stability than AgNW networks. During cyclic bending tests to 10,000 cycles at 5 mm bending radius and even when almost folded with r_b of 1 mm, the resistivity changes were negligible because AgNWs were tightly held and adhered to the substrate by Ag films covering wires, thereby hindering fracturing of AgNWs under tension. Because the films were fabricated at a low temperature, there was no oxidation on the surfaces of the films. Hence, flexible organic light-emitting diodes (f-OLEDs) were successfully fabricated on polyethylene terephthalates (PET) coated with the hybrid films. The f-OLED in the bent state was comparable to that in the flat state, validating the potential applications of these transparent hybrid films as electrodes in various flexible electronics.     

电子组装中的可制造性设计

制造业的竞争日益激烈,降低产品成本、提高产品质量和缩短产品开发周期已成为企业生产和发展的关键。在这种形势下,并行工程作为一种有效的解决方案正在逐步发展起来。在并行工程环境下,面向制造的设计(DFM)是一项重要的技术,它通过在产品设计阶段充分考虑与制造有关的约束,全面评价产品设计和工艺设计,并提供改进的反馈信息,从而保证产品设计、工艺设计和制造一次成功,并尽可能降低制造成本。本文就电子产品组装过程中需考虑的一些可制造性设计因素进行阐述,希望能对相关工程设计人员有所帮助。     

中国印刷电子产业现状与前景展望

介绍了印刷电子的基本定义,印刷电子所涉及的产业领域,以及国外对印刷电子技术的研发投入情况。重点介绍了国内自2009年以来印刷电子的发展情况,特别是产业技术开发情况。分析了中国发展印刷电子产业的优势,并对未来印刷电子对中国一些产业领域的影响做了预测。     

Soluble carbon nanotubes/phthalocyanines transparent electrode and interconnection layers for flexible inverted polymer tandem solar cells

In this study, we focus on transparent electrodes for organic solar cells prepared from aqueous solutions consisting of single wall carbon nanotubes (SWCNTs) and a copper-phthalocyanine derivative (TSCuPc). We first investigated their electrical conductivity and optical properties. The high solubility level of the TSCuPc/SWCNTs enables the production of stable inks with high conductivity which allows obtaining flexible photovoltaic devices based TSCuPc/SWCNTs films with good performances. A power conversion efficiency of 3.2% was achieved in a device with a blend of poly (3-hexylthiophene-2,5-diyl):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) as the active layer with a TSCuPc/SWCNTs sprayed electrode on a polyethylene terephthalate (PET) substrate. TSCuPc and TSCuPc/SWCNTs were also employed as the electron transport layer (ETL) and the interconnecting layer (ICL) in an inverted tandem organic solar cell based on front P3HT–ICBA and back [70]PCBM–PCDTBT active layers, achieving an efficiency of 7.40%.     

Convection heat transfer in electrostatic actuated liquid droplets for electronics cooling

In this paper, the internal flow and heat transfer inside the electrostatic actuated droplets are studied for different droplet velocities by means of detailed flow computations. It is shown that the internal droplet flow exhibits a parabolic characteristic at one hand and that the presence of two convection cells decreases the heat transfer to the lower part of the droplet, thereby limiting the overall heat transfer through the droplet. A typical enhancement of the heat transfer with a factor 2 is achieved with respect to the minimal value that would be obtained assuming heat conduction as the only means of heat transfer in the liquid. Further an analytic lumped model is presented to estimate the transient average droplet temperature with an accuracy of 5% compared to the full transient computational fluid dynamics modelling.