Modulation of the electronic, optical and transport properties of graphene via chemical doping: Towards application as a transparent conductive electrodes
Motivation:
Graphene has emerged as a strong candidate as a transparent conductive electrodes (TCE) as a potential replacement for the popular Indium Tin oxide (ITO). This is due to the unique fundamental electronic, optical, mechanical and chemical properties of graphene. However, large scale production routes of graphene (currently most popular it the Chemical Vapor Deposition "CVD") is poly-crystalline and defective, resulting in a lower conductivity as compared to higher quality graphene. Hence to capture the advantage of the large-scale processability of CVD graphene, chemical doping can significantly reduce its sheet resistance, in addition to largely modifying its work function which enables universality of using graphene either as a low work function cathode or a high work function anode in optoelectronic applications. Approach:
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Chemical Vapor Deposition (CVD) of Graphene - optimization and clean transfer
Motivation:
Chemical vapor deposition (CVD) is currently the most promising route towards large-scale production of graphene, especially with very recent reports on the roll-to-roll adaptation of both the synthesis and transfer process. The properties and uniformity of CVD graphene are largely influence by the conditions using during it preparation and to a large extent by the transfer process. A proper optimization of both of these processes is an essential step for any laboratory working on graphene. Approach:
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Structural and Morphological changes to CVD graphene upon exposure to Oxygen plasma
Motivation:
Graphene oxide has emerged as a solution-processed route to produce graphene thin films. However, to be the conductivity of graphene oxide films are significantly higher than those of synthesized from CVD, and hence a reduction process is required to restore the properties of pristine graphene. However, it has been challenging to restore the structure of pristine graphene and achieve full removal of the oxide species. A better understanding of the structural, morphological and chemical evolution of the oxide species on graphene can aid in developing better strategies for reducing graphene oxide towards pristine graphene.
Approach:
Graphene oxide has emerged as a solution-processed route to produce graphene thin films. However, to be the conductivity of graphene oxide films are significantly higher than those of synthesized from CVD, and hence a reduction process is required to restore the properties of pristine graphene. However, it has been challenging to restore the structure of pristine graphene and achieve full removal of the oxide species. A better understanding of the structural, morphological and chemical evolution of the oxide species on graphene can aid in developing better strategies for reducing graphene oxide towards pristine graphene.
Approach:
- Controllable oxidation of an initially high quality pristine graphene (CVD Single Layer Graphene).
- Chemical and Structural analysis at each oxidation stage via XPS and Raman spectroscopy
- Monitoring the morphological changes via AFM.