Optically and electrically tunable graphene quantum dot–polyaniline composite films

Graphene quantum dot–polyaniline (PANI–GQD) composite films were synthesized by a chemical oxidation polymerization process. The optical properties of the PANI–GQD composite were studied by varying the mole concentration of PANI and the size of the GQDs. The Au/PANI–GQDs/ITO sandwich device was fabricated in order to investigate the transport properties of the composite. A stable hysteresis loop was observed in response to the applied voltage. By varying the PANI content and size of the GQDs, the area within the hysteresis loop and electrical conductance behavior of the device can be tuned in a controlled manner. Both the tunable luminescence and electrical hysteresis behavior are attributed to surface states of the GQDs. The PANI–GQD composite films are expected to find application in photonic devices.