▎ 摘　　要

NOVELTY - A graphene oxide thin film is formed on a substrate, and primary chemical reduction is carried out using a reducing agent. Secondary thermal reduction and nitrogen doping are carried out on the primarily chemically reduced graphene oxide thin film, and a transparent graphene film having enhanced conductivity and controllable work function is manufactured. USE - Manufacture of transparent graphene film for device used for liquid crystal display device, electronic paper display device, solar cell and organic electroluminescent device (all claimed). ADVANTAGE - The transparent graphene film having improved conductivity and controlled work function is manufactured with improved productivity. The graphene film provides solar cell having improved light efficiency. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) transparent graphene film having conductivity of 4900-5100 S/cm and thickness of 10 nm; and (2) organic electroluminescent device comprising an anode having the graphene film, a hole transport layer, a light-emitting layer, an electron transport layer and a cathode.