Enhanced efficiency of dye-sensitized solar cells (DSSCs) with polyaniline-decorated FeCo2O4 counter electrodes: Synthesis, characterization, and performance analysis

Abstract

In this work, FeCo₂O₄ (FCO)/polyaniline (PANI) composite has been prepared and its performance in DSSCs has been compared with pristine FCO, PANI and platinum (Pt). X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM) have been employed for the structural and morphological analyses. Contact angle measurement has been performed to examine the contact between electrode and electrolyte. Electrocatalytic effects have been investigated through cyclic voltammetry (CV) and Tafel polarization. Electrochemical impedance spectroscopy (EIS) has been carried out to study the internal resistance and charge transfer kinetics. The FCO exhibits flower-like nanosheets structure whereas the PANI shows irregular coral-reef structure. A similar flower-like morphology is observed in the FCO/PANI composite. The surface of the composite appears to be rough and porous, which improves the electrode-electrolyte contact, as supported from the contact angle measurement. The FCO/PANI composite exhibits the highest electrocatalytic activity and the lowest charge transfer resistance, followed by PANI, FCO and Pt. The efficiencies of DSSCs assembled with FCO, PANI, FCO/PANI and Pt counter electrodes are 4.22, 5.58, 6.38, and 3.58 %, respectively. Superior cell efficiency with FCO/PANI counter electrode is attributed to its rough and porous morphology, greater adherence on the FTO glass and higher I₃⁻ reduction rate.