| AVS 58th Annual International Symposium and Exhibition | |
| Surface Science Division | Friday Sessions |
| Session SS-FrM |
| Session: | Surface Science on Graphene |
| Presenter: | Yves J. Chabal, University of Texas at Dallas |
| Authors: | M. Acik, University of Texas at Dallas C. Gong, University of Texas at Dallas G. Lee, University of Texas at Dallas K. Cho, University of Texas at Dallas C. Mattevi, University of Texas at Dallas M. Chhowalla, University of Texas at Dallas Y.J. Chabal, University of Texas at Dallas |
| Correspondent: | Click to Email |
Graphene devices are based on finite size flakes (e.g. nanoribbons) in contact with dielectrics or other materials, and therefore require control of edges and depend on the control of processing methods (often involving vapor or wet chemistry). Graphene oxide (GO) represents an interesting system from which much can be learned about oxygen interaction with graphene. Furthermore, studying the reduction of GO provides a powerful way to understand the stability of oxygen species and the role of trapped molecules. We have studied both the thermal and chemical reduction of single- and multi-layer GO using in situ infrared (IR) absorption spectroscopy under a variety of conditions. For the commonly used as-synthesized GO, we find that water molecules play an important role in both defect formation (evident from CO2 evolution)1 and carbonyl-termination of defect edges at intermediate annealing temperatures (150-250 C).2 We also find that a very stable edge configuration appears after high temperature anneals (> 850C), involving edge-ether termination of atomically straight zigzag edges and characterized by an anomalously strong IR absorption.3 The situation is dramatically different when water is replaced by alcohols or more complex molecules (e.g. ionic liquids). In general, defect formation is greatly suppressed (no CO2 evolution) with less carbonyl formation and a reduced density of atomically straight, edge-ether terminated edges. This talk will summarize the current understanding of the mechanisms involved in thermal reduction and suggest pathways for developing stable graphene nanostructures with reasonable electrical properties.
1. Acik et al., Generation and capture of CO2 and CO in graphite oxide stacks during thermal reduction Mater. Res. Soc. Symp. Proc., 1205E, 1205 (2010).
2. Acik et al., The Role of Intercalated Water in Multilayered Graphene Oxide. ACS Nano 4, 5861 (2010).
3. Acik et al.,Unusual infrared-absorption mechanism in thermally reduced GO. Nature Materials 9, 840 (2010).