Polyaniline/graphene nanocomposites as counter electrode materials for platinum free dye-sensitized solar cells (DSSCSs)

•Nanocomposites of graphene/polyaniline were synthesized via in-situ polymerization method.•These composites were employed as catalyst materials for the counter electrode of DSSCs.•SEM analysis of PANi/GR shows PANi particles are well adhered to the surface of graphene sheets.•Cyclic voltametery, chronoamperometery and Tfael test confirm that catalyst are electrochemically stable.•DSSC with PANi/9%GR shows the PCE of 7.45%, slightly lower than Pt based device (7.63%). The objective of this work is to fabricate the efficient and Pt-free DSSCs. Nanocomposites of PANi/graphene have been synthesized via in-situ polymerization of aniline in the graphene acidic dispersion. The morphology and the distribution of particles in composites have been analyzed by Scanning Electron Microscopy (SEM). The electrochemical performance of PANi/Graphene nanocomposites has been investigated by Tafel test. Results found here show that the graphene/polyaniline composites as catalyst materials show an outstanding electrochemical activity in DSSCs. Under optimal conditions, DSSC with PANi/Graphene shows the power-conversion-efficiency (PCE) of 7.45%, which is slightly lower than that of Pt-based DSSC (7.63%) fabricated under similar conditions.