Dye-sensitized solar cells based on flower-shaped α-Fe2O3 as a photoanode and reduced graphene oxide-polyaniline composite as a counter electrode

We demonstrated an environmentally friendly photoanode composed of nano-flower structured hematite (alpha-Fe2O3) and a photocathode composite made of reduced graphene oxide-polyaniline (PANI-RGO) for efficient dye-sensitized solar cells (DSSCs). The porous petals-root structure of the alpha-Fe2O3 film characterized by different structural means (XRD, SEM, HRTEM, SAED and N-2 adsorption-desorption) was demonstrated to provide an efficient pathway for the charge carrier transfer of DSSCs. The incident photon-to-electron conversion efficiency (IPCE) profiles suggested a broad photo-response spectral region of up to 700 nm in the presence of nano-flower alpha-Fe2O3 in the photoanode. The PANI-RGO composite coated on the counter electrode was proven to have a higher photon-to-electron conversion efficiency than the conventional Pt, which is attributed to the improved electro-catalytic activity and conductivity of PANI-RGO. It was found that the energy conversion efficiency (1.24%) achieved from PANI-RGO as photocathode material is increased by a factor of 1.3 compared with Pt. The better electro-catalytic activity of PANI-RGO CE is brought about by a synergistic effect between PANI and RGO, which was verified by micro-Raman spectroscopy and electrochemical characterizations (CV, EIS).