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

Abstract

In this work, nickel selenide (NiSe2) and iron selenide (FeSe2) 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 NiSe2 presents an irregular flaky-like structure whereas the FeSe2 forms a non-uniform rods structure. The catalytic effects of NiSe2 and FeSe2 in comparison to Pt were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FeSe2 exhibits the highest catalytic activity and the lowest charge transfer resistance, followed by Pt and NiSe2. 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 NiSe2, FeSe2 and Pt counter electrodes. The efficiencies attained for NiSe2, FeSe2 and Pt counter electrodes are 6.05, 7.20 and 6.99%, respectively. The FeSe2 demonstrates better corrosion resistance to the iodide/triiodide (I−/I3−) electrolyte than Pt.