Graphene in Electronics

Light-emitting diodes (LEDs) are basically a light-emitting polymer pinned between two electrodes externally connected to a power supply, where the cathode furnishes electrons to the LUMO of the polymer and the anode injects holes in the HOMO of the polymer. Once the electrons and holes recombine into the bulk of the polymer an exciton is produced which then releases its energy in the form of electromagnetic radiation [289]. Peumans et al. demonstrated the use of graphene as transparent electrodes 

Recently, the emerging need for high-speed electronics and renewable energy has motivated researchers to discover, develop and assemble new types of nanomaterials. Among the different carbon allotropes, graphene 

---

Graphene, the two-dimensional form of carbon, also shows great promise, and its study has attracted two Nobel Prizes and considerable research activity (Chabot et al., 2014). A report for the US Army Laboratory notes the potential for graphene in electronic textiles (Nayfeh et al., 2011). 

It often becomes necessary to prepare dispersions of graphene in organic or aqueous media [73-74]. For this purpose, different approaches have been successfully employed for few-layer graphene. The two main approaches for obtaining this type of graphene are covalent functionalization or by means of noncovalent interactions. There has been some recent effort to carry out covalent and noncovalent functionalization of graphene with aromatic molecules, which help to exfoliate and stabilize the individual graphene sheets and to modify their electronic properties [75 84]. 

In any case, it is safe to conclude that solving all the aforementioned concerns is just a matter of time. Once they have been dealt with, the industrial production of carbon-based printable DSSCs as well as the common use of graphene hybrids in electronic devices will become a reality. 

The purpose of this review is to present recent developments on the utilization of fullerenes, carbon nanotubes, and graphene in molecular electronics. 

Discovered in 2004, graphene is a so-called super material made up of single layers of graphite as shown in the upper diagram of Figure 3.32a. It is able to conduct electricity one million times better than copper metal and has enormous potential in electronics. 

For further evolution of the probe nanotechnology we should have new types of fine probes. We have developed focused ion beam (FIB) methods for silicon probe modification and sharp pointing. They are very powerful for the fabrication of probes with desirable properties and orientations. Fig. 3 displays the application of this method for integrated CNT and graphene based electronics and nanosystems in mass production. 

The production of graphene via the reduction of graphite oxide was first described by Hanns-Peter Boehm, an X-ray crystallographer, who isolated and identified a few, or even single, graphene sheets with transmission electron microscopy and X-ray diffraction in 1962 (Fig. 4.10) (Boehm et al., 1962). Boehm authored the International Union of Fhire and Applied Chemistry (lUPAC) report defining the term graphene in 1994. The production of... 

Graphene is a material made of carbon arranged in a flattened buckyball pattern. It has many potential uses in electronics and other mechanical and engineering applications. 

Success has recently been reported in preparing silicene, the silicon equivalent of graphene, on a silver substrate.2 Like graphene and other two-dimensional forms of carbon, silicene is anticipated to have promising applications in electronics. 

See C. N. R. Rao, K. Biswas, K. S. Subrahmanyam, A. Govindaraj, J. Mater. Chem., 2009,19, 2457 for a useful review of graphene s synthesis and properties, including electronic properties that are beyond the scope of this text. This review includes images of graphene in single and multiple layers. 

The extraordinary electronic properties of graphene have spurred the search for other two-dimensional carbon allotropes. Graphene s electronic properties are related to its exhibiting Dirac cones and points, where the valence and conduction bands meet at the Fermi level at these points it may be considered a semiconductor with a zero band gap. The allotrope 6,6,12-graphyne has been predicted to have two nonequivalent types of Dirac points—in contrast to graphene, in which all Dirac points are equivalent—and may therefore have more versatile applications. ... 

Isoniemi, T., Tuukkanen, S., Cameron, D.C., Simonen, J., Toppari, J.J., 2015. Measuring optical anisotropy in poly (3, 4-ethylene dioxythiophene) poly(styrene sulfonate) films with added graphene. Org. Electron. 25, 317-323. 

---