Work Function Engineering of Graphene

Abstract

Graphene is a two dimensional one atom thick allotrope of carbon that displays unusual crystal structure, electronic characteristics, charge transport behavior, optical clarity, physical & mechanical properties, thermal conductivity and much more that is yet to be discovered. Consequently, it has generated unprecedented excitement in the scientific community; and is of great interest to wide ranging industries including semiconductor, optoelectronics and printed electronics. Graphene is considered to be a next-generation conducting material with a remarkable band-gap structure, and has the potential to replace traditional electrode materials in optoelectronic devices. It has also been identified as one of the most promising materials for post-silicon electronics. For many such applications, modulation of the electrical and optical properties, together with tuning the band gap and the resulting work function of zero band gap graphene are critical in achieving the desired properties and outcome. In understanding the importance, a number of strategies including various functionalization, doping and hybridization have recently been identified and explored to successfully alter the work function of graphene. In this review we primarily highlight the different ways of surface modification, which have been used to specifically modify the band gap of graphene and its work function. This article focuses on the most recent perspectives, current trends and gives some indication of future challenges and possibilities.

Modulation of the exfoliated graphene work function through cycloaddition of nitrile imines

“…In this sense, the possibility of adjusting the work function through chemical functionalization makes graphene a very promising material in the semiconductor field. 29 Band-gap opening has been demonstrated after in situ doping, 30 chemical doping, 31 electrochemical doping 32 or BN doping of chemical vapor deposited graphene. 33 The WF of graphene can be tuned by using different methods, such as the electric field effect, 34 chemical doping with heteroatoms, 35 or chemical functionalization.…”

Solution-Processed rGO/AgNPs/rGO Sandwich Structure as a Hole Extraction Layer for Polymer Solar Cells

“…In case of HEL, the work function is found to be 4.9 eV, which is similar to the work function of graphene doped with AgNPs. Garg et al demonstrated that the work function of graphene could be tuned from 4.3 eV to 5.0 eV by introducing Ag [12]. According to Figure 3(b), we have encountered that the work function of GO can be easily tuned to a value lower or higher than that of ITO by being reduced with hydrazine or sandwiched with AgNPs, respectively.…”

Role of Graphene in Photocatalytic Solar Fuel Generation

“…Graphene is a zero band gap semimetal with a small overlap between its HOMO and LUMO [12][13][14]. In fact, the electrical, mechanical, optical, and thermal properties of graphene are very similar to those of single-walled carbon nanotubes (SWCNTs), while it can be prepared at significantly lower cost [11].…”