Graphene-Based Polymer Nanocomposites in Electronics

Discovery of graphene nanolayers has made a big bang in nanotechnology and many industrial innovations have come up as a result. Graphene and its derivatives filled polymers also contribute towards the fabrication of numerous electronic and mechanical devices such as sensors, capacitors, tyres, shields etc. In this regard a detailed survey of this topic has utmost importance mainly focusing on the application side. This chapter is aimed at providing a brief introduction about various graphene nanocomposite systems, its major properties especially relevant in electronics and a few applications. We also discuss the thermal, piezoelectric, optoelectric and actuating properties of graphene polymer nanocomposites in addition to the electromagnetic interference shielding and ferroelectric performances.

Graphene, a monolayer of sp² hybridized carbon atoms arranged in a two dimensional lattice has attracted electronic industrial interest due to its exceptional electrical properties. One of the most promising applications of this material is in polymer nanocomposites in which the interface of graphene based materials and polymer chains merge to develop the most technologically promising devices. This chapter presents the electrical properties of such graphene based polymer nanocomposites and also discusses the effect of various factors on their electrical conductivity. Graphene enables the insulator to conductor transition at significantly lower loading by providing percolated pathways for electron transfer and making the polymers composite electrically conductive. The effect of processing conditions, dispersion, aggregation, modification and aspect ratio of graphene on the electrical conductivity of the graphene/polymer nanocomposites is conferred.

High permittivity polymer-based composites are highly desired due to their potential applications as high energy density capacitors and inherent advantages of easy processing, flexibility and light weight. Graphene, a two-dimensional nanomaterial with a layer thickness of one atom, has showed many outstanding properties and aroused tremendous research enthusiasm. Its large aspect ratio, high surface area and high electric conductivity make it an ideal filler for fabricating polymer-based percolative nanocomposites with high dielectric performance. This chapter reviews progresses in graphene-filled polymer nanocomposites with high permittivity that have been made over the past few years. The basic theory of percolation and the interface effect of graphene/polymer on the dielectric properties of nanocomposites are discussed.

Graphite and its derivative materials are widely used in fabricating energy harvesters and are known as materials of this generation. The excellent applications of these materials in technology come from their superior electronic properties. Piezoelectric, Actuator and other tactile materials based on graphene have come up with substantially improved properties. The present chapter deals with these aspects of graphene filled polymer nanocomposites where a thorough investigation of the design and properties of them is carried out. Effect of homogeneous distribution of graphene within the matrix, interfacial interaction and functionalization of fillers are discussed to bring dynamic control to nanoscale actuators and piezoelectrics. In addition to explaining the fundamental requirements to make the best piezoelectric and actuator materials, the existing confronts to guide future progress is also undertaken in this study.

Fuel cells have long been considered as highly efficient devices for energy conversion which transform chemical energy directly into electricity, without any venomous pollutants emitted into ambient environment. In recent years, graphene-polymer nanocomposites have attracted intense interest as functional components in fuel cells. This chapter focuses on the potential applications of graphene-polymer composites in fuel cells. Recent advancement in the synthesis of graphene, polymer, graphene-polymer composites will be presented. Then, latest explorations of graphene-polymer composites applied as membranes, anode and cathode materials will be summarized. Furthermore, the vital roles of graphene-polymer to support noble metal catalysts will be illustrated. Finally, prospects of graphene-polymer composites for fuel cells will be outlined for further development.

As a kind of emerging two-dimensional (2D) materials, graphene has attracted worldwide attentions both in fundamental studies and practical applications across many fields such as physics, chemistry, materials and electronics. Here, we will survey the recent advances in optoelectronics properties of graphene and graphene nanocomposites, as well as their potential applications. Moreover, the chemistry, the preparation techniques, and the structure–property relationships of the graphene nanocomposites would be highlighted.

Graphene—a two-dimensional lattice oriented monolayer of sp²-hybridized carbon atoms—has taken up considerable attention leading to a growing scientific interest due to its exceptionally high electrical conductivity (orders of magnitude higher than copper), optical transparency (>90 %), chemical robustness (more than 500 °C) and mechanical stiffness (more than 1,000 GPa) as well as high specific surface area. Design and development of graphene incorporated polymer photovoltaics is one of the promising routes to harness the extraordinary properties of graphene for the generation of efficient solar-to-power conversion devices. Graphene as well as its chemically functionalized forms, graphene oxide (GO) and reduced-GO, are the smart materials for photovoltaic cells performing specific functions depending upon their intriguing properties. Herein we review the multifunctional and practical applicability of graphene and its composite materials as the electron acceptor, counter electrode and hole transport components of polymer solar cells. We conclude the chapter with the present scenario and challenges related to the stability and commercialization of graphene–polymer based photovoltaic devices.

Graphene is an amazing material with unique electrical and optical properties that have never been observed in conventional materials. Graphene can absorb light from ultraviolet to infrared and transit carriers at a speed of 1/300 of light, which make graphene an excellent candidate for optoelectronic applications. Graphene composites consisting of graphene and other materials combine the high carrier mobility property of graphene and the excellent light absorption properties of other semiconductors, which are ideal for development of next-generation optoelectronic devices, especially photodetectors. In this chapter, we review the recent progress of graphene composite photodetectors with significant performance improvement compared to the original graphene photodetectors and discuss its future developments. We consider that graphene composite photodetectors would play an important role in future optical interconnect and imaging systems.

The purpose of this chapter is to give a review of the polymer/nanographite composite (PNGC) materials specially developed for applications in mechanical strain and pressure sensors that can be used for design of flexible sensing systems. Our recent achievements in design, processing, and investigation of physical properties of elastomer and nanostructured carbon composites as prospective materials for mentioned sensors are also presented. In the beginning, theoretical principles of tunneling percolation theory and piezoresistivity have been described. We discuss the most suitable polymer matrices and electrically conductive nanographite fillers for sensitive PNGC. Preparation methods of mechanically sensitive PNGC have been considered. Different particularly produced and tested polymer/nanographite composites are overhauled and possible advantages and disadvantages of PNGC in different possible applications are analyzed.

With their unique and excellent properties such as high carrier mobility and high surface area, graphene-base materials have shown great promise as efficient sensing materials for highly sensitive and low noise sensors. Graphene offers some important advantages over other carbon-based materials such as carbon nanotubes (CNTs), which includes enhanced sensitivity and low inherent electrical noise. These merits mainly comes from their structural features, as it is composed of all surface carbon atoms with large and flat geometry enabling high sensitivity and low contact resistance. Moreover, their surface can be functionalized with organic molecules (e.g., polymers, nanocrystalline, bio-molecular), and surface molecules on graphene surface can also be used as gas/vapor sensing materials that promote the sensing capability of overall composites. This has sparked interests in the development of highly sensitive and selective gas/vapor sensors based on graphene-based materials and their polymer composites. In this review, recent progress on graphene and its composites will be discussed in the context of their use in sensors. It mainly focuses on how engineering graphene with other functional molecules can affect their ability to detect a number of different gas/vapor. It also emphasizes achievements made with graphene-filled polymer composites for gas/vapor sensor applications.

A major application identified for graphene/polymer nanocomposites is as electromagnetic (EM) wave absorbers in high frequency electronics which is the backbone of present day communication systems. In this application area, thin and flexible absorbers are essential for ensuring electromagnetic interference (EMI)/EM compatibility standards. Presently, communication modes are primarily mobile in nature and inherently light weight and small in size. In this context, there is a great demand for high performance novel absorbing materials that can offer required solutions. The properties of graphene-filled polymer nanocomposites clearly make them outstanding candidates for microwave absorption. Graphene as a filler is quite unique as it offers the highest surface-to-volume ratio and hence once it is incorporated inside a polymer matrix it offers increased conductive and dielectric loss without a large increase in impedance mismatch. It is possible to disperse graphene in some polymers uniformly and hence their large surface-to-volume ratio becomes advantageous. Once they are well dispersed in the host, the composite can be imagined as a kind of distributed capacitors combining in series and parallel resulting in reduced capacitance but increased dissipation, yielding impedance-matched absorber. Graphene can be functionalized with various functional groups giving an additional degree of freedom to fine-tune its properties. This in turn increases the flexibility in designing novel graphene-based materials. For an absorber, not only its EM response but its mechanical, adhesive, and weatherability characteristics are also important. Since meeting the EM absorption requirement over a range of frequencies by a single material is difficult, the possibility of functionalization of graphene opens up many opportunities and hence graphene/polymer nanocomposites open up scope for a wide spectrum of combinatorial investigations that are able to give solutions for the emerging scenario where in the usage of microwave spectrum is becoming more widespread, rather than not merely confined to the strategic sector as it used to be.

The unique properties of graphene, such as high specific surface area, aspect ratio and electrical conductivity, make it very promising to fabricate electromagnetic induction (EMI) shielding materials. In this chapter, we firstly made a brief introduction about the development of EMI shielding materials as well as the preparation of graphene and polymer/graphene nanocomposites (PGNs). Typical surface modification of graphene to optimize its dispersion within polymer matrix was reviewed later. After that, we presented critical factors for the EMI shielding effectiveness (SE) of PGNs in detail. Meanwhile, the EMI shielding mechanism was introduced associated with corresponding examples.