Development of cost-effective counter electrodes (CEs) and enhancement of power conversion efficiency are two persistent objectives for dye-sensitized solar cells (DSSCS). We report a novel method for synthesizing the state of art polyaniline nanoribbons (PANI NRs) CE with serrated, flexible and ultrathin nanostructure by in situ polymerization of aniline on an inorganic template, followed by acid etching. Herein, electrospun vanadium pentoxide (V2O5) nanofibers are chosen as templates to deposit PANI by a chemical bath polymerization method, which are served as the oxidants as well. Owing to its abundant active sites and the good contact performance, the PANI NRs CE shows high catalytic activity and the DSSC based on the PANI-c NRs CE shows a photoelectric conversion efficiency of 7.23% under full sunlight illumination (100 mW cm(-2), AM 1.5 G), which is 97.44% that of the Pt-based DSSC (7.42%). Therefore, the high performance of PANI NRs can be considered as a cost-effective CE for the DSSC. (C) 2016 Elsevier B.V. All rights reserved.