The effect of transition metal ions (M2+=Mn2+,Ni2+,Co2+,Cu2+) on the chemical synthesis polyaniline as counter electrodes in dye-sensitized solar cells

The effect of transition metal ions(M=Mn,Ni,Co,Cu) on the chemical synthesis of polyaniline(PANI) used as a platinum-free counter electrode(CE) in dye-sensitized solar cells(DSSCs) was investigated.PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide(I~-/I~-) redox couples. The power conversion efficiency(η) of PANI CEs doped with Mn,Ni,Co(4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cudecreased the power conversion efficiency of PANI CE(PANI-Cuη = 1.41%). The electrical properties of the PANI, PANI-Ni, PANI-Co,PANI-Mnand PANI-Cuwere studied by cyclic voltammetry(CV), impedance(EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions(M=Mn,Ni,Co,Cu). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.