Graphene: The magic material for future electronics and energy conversion
Feb. 20, 2013
Cover
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Carbon is one of the most fundamental, spread, versatile and diverse elements for life. It is also at the center of modern nanotechnology and holds significant promise as the leading material for future electronics.Since its isolation by the Nobel Laureates Geim and Novoselov in 2004, graphene, a material consisting of pure hexagonal carbon layers, has gathered gargantuan interest due to its unique properties. The electronic characteristics of graphene are particularly exciting, so much that some even claim graphene could render current silicon based technology obsolete. Recently, the EU decided in the framework of its flagship-initiative to fund graphene research and development in the next 10 years with 1 Billion Euro to exploit the enormous potential this material bears.

Two recent publications from TU Dresden in the renowned Nature journal Scientific Reports emphasize the enormous potential which graphene possesses for future applications. Whilst graphene promises so much, significant hurdles remain in being able to reliably produce graphene with sufficient quality and structural precision so as to enable its use in mass device fabrication. Scientists from TU Dresden and the IFW Dresden teamed up with a top team from Delft University (Netherlands) and showed in their article how one can get disordered carbon atoms, known as amorphous carbon, to re-arrange into a highly ordered perfectly arranged two-dimensional honeycomb lattice forming pure and defect-free graphene layers (Figure 1). "It is amazing to witness disordered atoms to re-arrange themselves into crystalline graphene layers", says Dr. Mark H. Rümmeli of TU Dresden and the IFW Dresden. "The process developed by our team goes even one step beyond producing graphene: Unwanted defects in the material can be healed by itself, making it highly reliable for different applications in modern electronics" Rümmeli continues.

The second article deals with the thermal characteristics of graphene. One of the superlatives of graphene is that it is the material with the highest thermal conductivity, which implies that graphene is not expected to be a promising material for thermoelectrics, which is the conversion of temperature differences to electrical currents and vice versa. But combined with the fact that graphene can easily be tailored in many different ways, it could in fact be an extremely efficient component for thermoelectric applications (link). The method for tailoring graphene for thermoelectrics proposed by this group of scientists from TU Dresden, Technical University of Denmark, Anadolu University (Turkey) and Texas A&M University (USA) relies on a bottom-up scheme: ribbons of graphene are synthesized starting from precursor molecules which are made up of different isotopes of carbon (Figure 2). In their simulations the scientists show that the thermal conductivity can be reduced by 98.8% without disturbing the electronic conduction quality which is necessary for a good thermoelectric material. As a result, figures of merit achieving the target values for technical applications can be obtained.

"It was not expected that graphene can be synthesized in such a simple way and that it can act as such an efficient thermoelectric converter. In both publications, we have shown novel routes in graphene research bringing this material closer and closer to application and readiness for the market" says Prof. Gianaurelio Cuniberti of TU Dresden, head of the Chair Materials Science and Nanotechnology where major parts of both projects were performed, and continues: "This work would not have been possible without our close collaboration in materials, microscopy and modeling from different institutions here in Dresden. This synergetic approach lies at the heart of the DRESDENconcept and the success enjoyed by the Dresden research community within the German Excellence Initiative. Clearly Dresden's research is making an impact and its visibility in the international community is continuously growing."

Graphene: The magic material for future electronics and energy conversion
Feb. 20, 2013
Cover
©None

Carbon is one of the most fundamental, spread, versatile and diverse elements for life. It is also at the center of modern nanotechnology and holds significant promise as the leading material for future electronics.Since its isolation by the Nobel Laureates Geim and Novoselov in 2004, graphene, a material consisting of pure hexagonal carbon layers, has gathered gargantuan interest due to its unique properties. The electronic characteristics of graphene are particularly exciting, so much that some even claim graphene could render current silicon based technology obsolete. Recently, the EU decided in the framework of its flagship-initiative to fund graphene research and development in the next 10 years with 1 Billion Euro to exploit the enormous potential this material bears.

Two recent publications from TU Dresden in the renowned Nature journal Scientific Reports emphasize the enormous potential which graphene possesses for future applications. Whilst graphene promises so much, significant hurdles remain in being able to reliably produce graphene with sufficient quality and structural precision so as to enable its use in mass device fabrication. Scientists from TU Dresden and the IFW Dresden teamed up with a top team from Delft University (Netherlands) and showed in their article how one can get disordered carbon atoms, known as amorphous carbon, to re-arrange into a highly ordered perfectly arranged two-dimensional honeycomb lattice forming pure and defect-free graphene layers (Figure 1). "It is amazing to witness disordered atoms to re-arrange themselves into crystalline graphene layers", says Dr. Mark H. Rümmeli of TU Dresden and the IFW Dresden. "The process developed by our team goes even one step beyond producing graphene: Unwanted defects in the material can be healed by itself, making it highly reliable for different applications in modern electronics" Rümmeli continues.

The second article deals with the thermal characteristics of graphene. One of the superlatives of graphene is that it is the material with the highest thermal conductivity, which implies that graphene is not expected to be a promising material for thermoelectrics, which is the conversion of temperature differences to electrical currents and vice versa. But combined with the fact that graphene can easily be tailored in many different ways, it could in fact be an extremely efficient component for thermoelectric applications (link). The method for tailoring graphene for thermoelectrics proposed by this group of scientists from TU Dresden, Technical University of Denmark, Anadolu University (Turkey) and Texas A&M University (USA) relies on a bottom-up scheme: ribbons of graphene are synthesized starting from precursor molecules which are made up of different isotopes of carbon (Figure 2). In their simulations the scientists show that the thermal conductivity can be reduced by 98.8% without disturbing the electronic conduction quality which is necessary for a good thermoelectric material. As a result, figures of merit achieving the target values for technical applications can be obtained.

"It was not expected that graphene can be synthesized in such a simple way and that it can act as such an efficient thermoelectric converter. In both publications, we have shown novel routes in graphene research bringing this material closer and closer to application and readiness for the market" says Prof. Gianaurelio Cuniberti of TU Dresden, head of the Chair Materials Science and Nanotechnology where major parts of both projects were performed, and continues: "This work would not have been possible without our close collaboration in materials, microscopy and modeling from different institutions here in Dresden. This synergetic approach lies at the heart of the DRESDENconcept and the success enjoyed by the Dresden research community within the German Excellence Initiative. Clearly Dresden's research is making an impact and its visibility in the international community is continuously growing."