NOVELTY - Manufacturing graphene, comprises: (a) preparing a subject substrate; (b) forming a metal thin film on the subject substrate and heat-treating the metal thin film; (c) supplying a carbon source material; (d) heating the supplied carbon source material, the subject substrate, and the metal thin film; (e) diffusing carbon atoms; and (f) forming graphene on the subject substrate by the carbon atoms diffused through the metal thin film.    USE - The method is useful for manufacturing graphene, where the graphene is used in a transparent electrode, and an active layer (claimed).    ADVANTAGE - The method is cost effective and efficiently produces a highly improved graphene which can be used in producing transparent electrode used in display devices.    DETAILED DESCRIPTION - Manufacturing graphene, comprises: (a) preparing a subject substrate; (b) forming a metal thin film on the subject substrate and heat-treating the metal thin film to increase the grain size of the metal thin film; (c) supplying a carbon source material on the metal thin film; (d) heating the supplied carbon source material, the subject substrate, and the metal thin film; (e) diffusing carbon atoms generated from the heated carbon source material due to thermal decomposition into the metal thin film; and (f) forming graphene on the subject substrate by the carbon atoms diffused through the metal thin film. INDEPENDENT CLAIMS are:    (1) a transparent electrode comprising the graphene;    (2) an active layer comprising the graphene;    (3) a display comprising the transparent electrode;    (4) an electronic device having the active layer;    (5) an optoelectronic device comprising: an anode; a hole transport layer (HTL); an emission layer; an electron transport layer (ETL); and a cathode, where the anode is the transparent electrode;    (6) a battery comprising the transparent electrode;    (7) a solar cell comprising the transparent electrode; and    (8) a dye-sensitized solar cell, comprising a semiconductor electrode, an electrolyte layer, and an opposed electrode, the semiconductor electrode comprises a transparent electrode and. a photoabsorption layer, and the photoabsorption layer comprises a nanoparticle oxide and a dye, where the transparent electrode and the opposed electrode are the transparent electrode.