Evaluation of treatment effects for high-performance dye-sensitized solar cells using equivalent circuit analysis

Abstract

Equivalent circuit analysis using a one-diode model was carried out as a simpler, more convenient method to evaluate the electric mechanism and to employ effective treatment of a dye-sensitized solar cell (DSC). Cells treated using acetic acid or 4, t-butylpyridine were measured under irradiation (0.1 W/m 2, AM 1.5) to obtain current–voltage ( I– V) curves. Cell performance and equivalent circuit parameters were calculated from the I– V curves. Evaluation based on residual factors was useful for better fitting of the equivalent circuit to the I– V curve. The diode factor value was often over two for high-performance DSCs. Acetic acid treatment was effective to increase the short-circuit current by decreasing the series resistance of cells. In contrast, 4, t-butylpyridine was effective to increase open-circuit voltage by increasing the cell shunt resistance. Previous explanations considered that acetic acid worked to decrease the internal resistance of the TiO 2 layer and butylpyridine worked to lower the back-electron-transfer from the TiO 2 to the electrolyte.