Multiscale simulation of dye-sensitized solar cells considering schottky barrier effect at photoelectrode

The effect of the TiO₂/transparent conducting oxide (TCO) interface in a photoelectrode of a dye-sensitized solar cell (DSSC) on its cell performance was investigated using our multiscale simulator, in which we had added a calculation of the voltage loss derived from the Schottky barrier height (SBH) at the TiO₂/TCO interface to our previous simulator. We treated the TiO2/TCO interface as a series connection of a Schottky diode of metal/n-type semiconductor. The thermionic-emission theory was applied to describe the electron transfer and the voltage loss at the TiO₂/TCO interface. The accuracy of the prediction of the current density-voltage (J-V) characteristics of a DSSC employing the cisdithiocyanato- bis(2,2'-bipyridyl-4, 4'-dicarboxylic acid)-ruthenium(II) (N3 dye) was improved compared with that obtained by our previous simulator. The effects of the SBH on the open circuit voltage (V_OC) and the maximum power output (P_max), as well as the J-V characteristics, of the DSSC were discussed. Our results suggest that a TCO with the SBH ≤ 0:5 is suitable for a DSSC.