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Báo cáo hóa học: " A novel mechanical cleavage method for synthesizing few-layer graphenes"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: A novel mechanical cleavage method for synthesizing few-layer graphenes | Jayasena and Subbiah Nanoscale Research Letters 2011 6 95 http www.nanoscalereslett.eom content 6 1 95 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access A novel mechanical cleavage method for synthesizing few-layer graphenes Buddhika Jayasena Sathyan Subbiah Abstract A novel method to synthesize few layer graphene from bulk graphite by mechanical cleavage is presented here. The method involves the use of an ultrasharp single crystal diamond wedge to cleave a highly ordered pyrolytic graphite sample to generate the graphene layers. Cleaving is aided by the use of ultrasonic oscillations along the wedge. Characterization of the obtained layers shows that the process is able to synthesize graphene layers with an area of a few micrometers. Application of oscillation enhances the quality of the layers produced with the layers having a reduced crystallite size as determined from the Raman spectrum. Interesting edge structures are observed that needs further investigation. Introduction There is an urgent need to develop a large-scale method to manufacture graphene reliably for various promising applications being developed 1 . These applications rely largely on the unique properties of graphene 2 3 and the properties are strongly affected by the method of synthesis 4 . While several laboratory methods to synthesize graphene have been developed and reported the suitability of these methods to large-scale manufacturing remains to be proven. These methods can be broadly classified as epitaxial growth colloidal suspension unconventional methods and exfoliation. In the epitaxial growth method graphene can be grown on top of either metallic or insulator substrates using physical and chemical vapour deposition methods 2 4 5 . In the colloidal suspension method a combination of aqueous or organic solvent with an initial raw material such as graphite oxide is used 2 . There are also several unconventional methods such as unzipping carbon nanotubes CNT .