The applicability of SWCNT on the counter electrode for the dye-sensitized solar cell

In this study, two types of the counter electrode were designed and fabricated for the dye-sensitized solar cell (DSSC): (1) one had a layer of SWCNT/Ag on the FTO-glass (Fluorine doped tin oxide, SnO2:F) substrate; (2) the other had a layer Ag sandwiched between a layer of SWCNT and the FTO-glass substrate. This study also examined the effects of the mass ratio of SWCNT to Ag-paste, the surfactant (such as TOAB), the type of FTO-glass substrate, and the sintering temperature of preparing the counter electrode on the short-circuit photocurrent and the open-circuit photovoltage of the DSSC. At a fixed sintering temperature of 150 °C and a fixed FTO-glass substrate of 8 Ω/sq, this film of SWCNT markedly increased the short-circuit photocurrent from 227.3 μA (conventional DSSC without a layer of SWCNT) to 1033.5 μA (DSSC with a layer of SWCNT/Ag). Most importantly, at a fixed FTO-glass substrate of 8 Ω/sq, this study shows that the short-circuit photocurrent of the DSSC with a layer Ag sandwiched between a layer of SWCNT and the FTO-glass substrate of the counter electrode (2565 μA) substantially exceeds that of DSSC with a thin film of platinum on the FTO-glass substrate of the counter electrode (1263.7 μA).