▎ 摘　　要

NOVELTY - Fabricating (M1) a graphene thin film, involves: (a) preparing graphene oxide; (b) preparing graphene through reducing the graphene oxide by a sulfonyl hydrazide-based reducing agent; (c) preparing a graphene dispersed solution by dispersing the graphene into an organic solvent; and (d) fabricating a graphene thin film by applying the graphene dispersed solution. USE - For fabricating a graphene thin film and an optoelectronic device including an organic solar cell or an organic light emitting diode (OLED) (claimed). ADVANTAGE - The method is stable, environment-friendly, and economical mass-production method; avoids the use of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS); and produces uniform thin film available for a solution process. The graphene thin film is stable; has high density and high conductivity; has a thickness of 0.5-10000 nm; and enhances a life span of an organic solar cell device by applying the thin film to an electrode or a buffer layer of the organic solar cell. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for fabricating (M2) an optoelectronic device involving forming a buffer layer, and an electrode layer, where the buffer layer and the electrode layer are formed according to the method (M1).