In this article, the method to fabricate a highly conductive graphene thin film from natural graphite powder through oxidation, exfoliation, deposition and reduction processes will be presented. Subsequently, the application of the graphene thin film to the electrodes of organic thin-film devices will be introduced.
  Chemically oxidized graphite powder was dispersed in water, and it was exfoliated by sonication or by repeated centrifugation and washing processes to obtain graphene oxide (GO). Successively a GO film was fabricated by coating a substrate with the GO solution, and it was chemically and thermally reduced to produce a highly conductive graphene film. Operation of organic thin film solar cells, which make use of the graphene films as their transparent electrodes, has been demonstrated. To date, the power-conversion ratio as high as 1% is achieved. Good operating performance of organic thin film field-effect transistors, which have graphene source/drain electrodes, is also demonstrated.