Ultrasonic irradiation preparation of graphitic-C3N4/polyaniline nanocomposites as counter electrodes for dye-sensitized solar cells

[Display omitted] •A new kind of low cost Pt-free counter electrode for DSSCs was prepared.•PANI/g-C3N4 NC was prepared by in-situ electrochemical polymerization under sonication.•PANI/g-C3N4 NCs how good catalytic activity in promoting tri-iodide reduction.•Physicochemical characterization was carried out by different techniques.•The DSSC NC electrode exhibits an energy conversion efficiency of 1.8%. In this research, polyaniline/graphitic carbon nitride (PANI/g-C3N4) nanocomposites were synthesized via in-situ electrochemical polymerization of aniline monomer whit different number of cyclic voltammetry scans (10, 20 and 30 cycles) after electrode surface pre-preparation using a potential shock under ultrasonic irradiation. PANI/g-C3N4 nanocomposites with two values of g-C3N4 (0.010 wt% and 0.015 wt%) were deposited on the surface of the transparent conducting film (FTO glass) by immersing FTO into the aniline solution and g-C3N4 during the electro-polymerization. The resulting PANI/g-C3N4 films were characterized by Fourier transformed infra-red (FTIR), power X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) techniques. The prepared electrodes were applied as counter electrode in dye-sensitized solar cells. Among them, the prepared electrode with 10 cycles and 0.01 wt% g-C3N4 showed the best efficiency. These hybrids show good catalytic activity in elevating tri-iodide reduction and due to the synergistic effect of PANI and g-C3N4, PANI/g-C3N4 nanocomposite electrode shows power conversion efficiency about 1.8%.