One-step synthesis of nano-scaled tungsten oxides and carbides for dye-sensitized solar cells as counter electrode catalysts

Nano-scaled tungsten oxides and carbides are synthesized using a simple one-step chemical method. They are subsequently introduced into dye-sensitized solar cells (DSCs) as counter electrode (CE) catalysts to replace the expensive Pt. The catalytic mechanism is investigated by measurements of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel-polarization curve for the as-prepared catalysts. The DSCs using WC/W2C, W2C and WO2 as CE catalysts yield high power conversion efficiency (PCE) of 6.23%, 6.68%, and 6.88%, respectively, comparable to that of the DSC using Pt CE. The results demonstrate that tungsten oxides and carbides are the potential alternative to the expensive Pt CE for reducing the cost of DSCs.