Elastic Properties of Chemically Derived Single Graphene Sheets

Elastic Properties of Chemically Derived Single Graphene Sheets

2008 | Cristina Gómez-Navarro, Marko Burghard, and Klaus Kern
The elastic properties of chemically derived single graphene sheets were investigated using tip-induced deformation experiments. The study focused on the mechanical and electrical properties of suspended, chemically reduced graphene oxide (GO) monolayers. Graphite oxide was prepared via the Hummers method, dispersed in water, and reduced by hydrogen plasma treatment. The resulting samples were suspended using wet etching and critical point drying. Atomic force microscopy (AFM) was used to characterize the mechanical properties, revealing a high stiffness (E = 0.25 TPa) and flexibility of the sheets, which is comparable to that of pristine graphene. The sheets exhibited excellent resilience, with their electrical conductivity remaining largely unchanged after multiple deformations. The electrical conductivity of the sheets was found to scale inversely with the elastic modulus, indicating the role of oxygen bridges in reinforcing bonds while impeding charge transport. The elastic modulus of the reduced GO monolayers was determined using the formula K_eff = 32Ew(t/l)^3 + 17T/l, where E is the elastic modulus, T is the tension, and w, t, and l are the width, thickness, and length of the beam, respectively. The results showed that the effective modulus (E_eff) was approximately 0.25 TPa, with a standard deviation of 0.15 TPa. The mechanical properties of the sheets were found to be significantly better than those of mechanically exfoliated graphene, with lower built-in tensions. The sheets also demonstrated excellent electrical stability, with resistance remaining largely unchanged after repeated deformation. The study highlights the potential of chemically reduced GO sheets for applications in nanoelectromechanical devices, such as resonators and sensors, due to their high mechanical strength, flexibility, and electrical conductivity.The elastic properties of chemically derived single graphene sheets were investigated using tip-induced deformation experiments. The study focused on the mechanical and electrical properties of suspended, chemically reduced graphene oxide (GO) monolayers. Graphite oxide was prepared via the Hummers method, dispersed in water, and reduced by hydrogen plasma treatment. The resulting samples were suspended using wet etching and critical point drying. Atomic force microscopy (AFM) was used to characterize the mechanical properties, revealing a high stiffness (E = 0.25 TPa) and flexibility of the sheets, which is comparable to that of pristine graphene. The sheets exhibited excellent resilience, with their electrical conductivity remaining largely unchanged after multiple deformations. The electrical conductivity of the sheets was found to scale inversely with the elastic modulus, indicating the role of oxygen bridges in reinforcing bonds while impeding charge transport. The elastic modulus of the reduced GO monolayers was determined using the formula K_eff = 32Ew(t/l)^3 + 17T/l, where E is the elastic modulus, T is the tension, and w, t, and l are the width, thickness, and length of the beam, respectively. The results showed that the effective modulus (E_eff) was approximately 0.25 TPa, with a standard deviation of 0.15 TPa. The mechanical properties of the sheets were found to be significantly better than those of mechanically exfoliated graphene, with lower built-in tensions. The sheets also demonstrated excellent electrical stability, with resistance remaining largely unchanged after repeated deformation. The study highlights the potential of chemically reduced GO sheets for applications in nanoelectromechanical devices, such as resonators and sensors, due to their high mechanical strength, flexibility, and electrical conductivity.
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Understanding Elastic properties of chemically derived single graphene sheets.