One-step electrodeposited CoSe2 nano-reticular with high electroconductivity and electrocatalytic as a counter electrode for dye sensitized solar cell

Herein, a nano-reticular structure cobalt diselenide (CoSe2) film with high electroconductivity and electrocatalytic has been synthesized by one-step electrodeposition method and is applied as a counter electrode for dye sensitized solar cell (DSSC). Cyclic voltammetry (CV) measurements with different potential windows are carried out to reveal the deposition mechanism of cobalt selenide, illustrating that the formation of CoSe2 occurred at −0.62 V via inductive effect reaction with selenide (Se2−). Tafel and CV characterizations demonstrate an excellent electrocatalytic activity of CoSe2 counter electrode towards I−/I3− reduction reaction, which is attributed to the electronic effect between Co and Se and electrochemical active sites, provided by wrinkled layer structure, for adsorption and reduction of I3−. EIS measurements show a great electroconductivity ability of electrodeposition CoSe2 film. The DSSC based on the CoSe2 counter electrode yields a maximum power conversion efficiency of 3.96% (Jsc = 10.84 mA cm−2, Voc = 0.65 V and FF = 55%) under the standard AM 1.5G illumination, which is 1.6 times higher than that of commercial Pt-based DSSC.