CoSe2/graphene composite: a low-cost, high performance counter electrode for dye sensitized solar cells
Abstract In this study, Pt-free dye-sensitized solar cells (DSSCs) were fabricated using cobalt selenide (CoSe2)/graphene sheets using facile hydrothermal technique. The Pt free counter electrode (CE) was systematically investigated their physico-chemical properties by using SEM, TEM, XRD, Raman, UV, PL, XPS and BET analysis. Under typical AM 1.5G illumination, the DSSC based on the CoSeSe2 counter electrode achieves a maximum PCE of 12.2 % (Jsc = 22.3 mA/cm2, Voc= 810 mV, and FF= 0.71), which is 5.8 times higher than that of conventional Pt-based DSSC. The improved electro catalytic activity and photo conversion efficiency of the CoSeSe2/graphene CE is due to prevent the recombination of electron-hole pair and extended the visible light absorption of composite samples.
