Making graphene applications lighter, cheaper, and more efficient

Amit Tewari is attempting to use graphene—the thinnest layer of graphite—to design electronic devices such as sensors, organic solar cells and organic transistors which will be lighter, more flexible, and cheaper than the ones currently available.

Amit is a research scholar at the IITB-Monash Research Academy, a Joint Venture between IIT Bombay and Monash University, which operates a graduate research programme in Mumbai. Research is conducted by scholars in both countries, while studying for a dually-badged PhD from both organizations.

Graphene, an ultrathin 2D material arranged in a honeycomb structure, has been blessed with numerous unprecedented properties such as high electrical and thermal conductivity, high elasticity, and transparency, which has made it the most studied nanomaterial. Graphite, one of the allotropes of carbon, is available abundantly in nature and is a parent material for extracting graphene.

Several research groups are working on techniques to obtain high quality and defect-free graphene in bulk that could be employed in various applications such as batteries, sensors, touch screen, coating against corrosion and electrode material in Organic Thin Film Transistors (OTFTs) and Organic Solar Cells (OSCs).

Fig. 1 Different techniques for synthesizing graphene along
with their applications

The methods that are currently being used to synthesise graphene require high investment with limited production, and are therefore difficult to commercialise. Furthermore, there are solution-based techniques for the synthesis scalable quantity of graphene through chemical exfoliation using additives and liquid-exfoliation using high shear forces; which are simple, cheap and eco-friendly.

Says Amit, "I am attempting to synthesize graphene through the chemical route focusing more on reducing the extent of defects and trap sites on graphene flakes that plays a key role in improving the performance of electrical equipments fabricated using it. The proposed techniques such as micro-mechanical cleavage of graphite, chemical vapor deposition (CVD), epitaxial growth on SiC (silicon carbide) substrate, arc discharge under required conditions are quite expensive and cannot be extended on a commercial scale."

Amit's project is challenging because he aspires to employ this obtained graphene for organic solar cells (OSC) as well as organic thin film transistors (OTFTs) either as an electrode or as one of its components, say active layer or electrode for charge collection. Besides, he needs a large area continuous sheet of graphene that is expected to reduce the scattering of charge carriers and thus lead to overall increment of electrical conductivity.

Fig. 2 The structure of the OTFT with bottom gate top contact (left) and Organic solar cell

Explaining his work so far, Amit says that the synthesis of graphene has been completed, and he now needs to determine which reduction technique (thermal or chemical) will provide the lowest sheet resistance (or high conductivity) – one of the key aspects of his research.

What delights Amit the most about his time at the Academy is that his project is multi-disciplinary, and can be applied to any field of science. "I studied physics during my master's, but for this project I need to develop a deep understanding of chemistry as well. The challenge is to obtain high quality graphene in large quantities with least investment."

Prof Murali Sastry, CEO of the IITB-Monash Research Academy is keenly monitoring Amit's progress. "I believe that the Academy will contribute strongly to high-impact research outcomes, and deliver a wide range of benefits – economic and societal – to India, Australia and the global community," he says.

With the help of researchers like Amit you may soon be able to replace your existing mobile phone with one that is more flexible, efficient, lighter, and, hopefully less expensive as well.

Research scholar: Amit Tewari, IITB-Monash Research Academy

Project title: Graphene Based Organic Electronic Devices

Supervisors: Prof. Dipti Gupta (Primary Supervisor); Prof. A. R. Bhattacharyya (Co-Supervisor) at IIT Bombay and Prof. Christopher McNeill (Primary Supervisor) at Monash University

Contact details: atewari2000@gmail.com

This story was written by Mr Krishna Warrier based on inputs from the research student and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.