Comparative study of nickel selenide, iron selenide and platinum on triiodide reduction for dye-sensitized solar cells

In this work, nickel selenide (NiSe 2 ) and iron selenide (FeSe 2 ) were synthesized by a simple and mild hydrothermal method . The selenides were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). XRD and EDX studies show the compositions of the products. The NiSe 2 presents an irregular flaky-like structure whereas the FeSe 2 forms a non-uniform rods structure. The catalytic effects of NiSe 2 and FeSe 2 in comparison to Pt were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FeSe 2 exhibits the highest catalytic activity and the lowest charge transfer resistance, followed by Pt and NiSe 2 . The photovoltaic and long-run performance of dye-sensitized solar cells (DSSCs) with poly( ε -caprolactone) (PCL)-dimethylformamide (DMF)-potassium iodide (KI) gel polymer electrolytes were investigated with respect to NiSe 2 , FeSe 2 and Pt counter electrodes. The efficiencies attained for NiSe 2 , FeSe 2 and Pt counter electrodes are 6.05, 7.20 and 6.99%, respectively. The FeSe 2 demonstrates better corrosion resistance to the iodide/triiodide (I − /I 3 − ) electrolyte than Pt.