▎ 摘　　要

NOVELTY - Producing graphene quantum ring, comprises (a) adding carbon fiber into a mixed solution of strong acid, and ultrasonically processing, (b) heat treating the ultrasonically processed solution, and drying the solution to obtain a mixture, and (c) diluting the obtained mixture, adjusting the pH, dialyzing and cooling and drying the mixture. USE - The graphene quantum ring is useful in field effect transistor and solar cell (all claimed), preferably hybrid (inorganic and organic) solar cells and photoelectric device. ADVANTAGE - The graphene quantum ring has excellent electrical and optical properties, and work function of -4.16 eV. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for graphene quantum ring having zigzag and armchair hollow structure at the center and laminated with graphene sheet of cylindrical shape.