Large thermoelectric power factor in polyaniline/graphene nanocomposite films prepared by solution-assistant dispersing method

Polyaniline (PANI)/graphene thermoelectric (TE) nanocomposite films with three types of graphene have been prepared by a solution-assistant dispersing method. The graphene nanoplates were aligned in the PANI matrix in the direction parallel to the substrate. The structural defects and oxygen content in the graphene had great influence on the TE performance of the PANI/graphene composites. The composite films prepared with graphene with lower structural defects and oxygen impurities showed higher TE properties. The maximum electrical conductivity and power factor of the composite film reached 856 S cm(-1) and 19 mu W m(-1)K(-2) respectively, which were the highest values among the reported polymer/graphene TE composites. These outstanding TE properties can be ascribed to the strong pi-pi conjugation interactions between PANI and low-defect graphene as well as to the solution process, which expands the PANI molecular conformation and therefore results in the enhancement of carrier mobility and electrical conductivity. This work provides a simple and effective approach to preparing polymer/graphene composite materials with high TE performance.