Journal of Physical Chemistry & Biophysics
Open Access

Abstract

Correlation between Dye-Sensitized Solar Cell Performance and Internal Resistance using Electrochemical Impedance Spectroscopy

Lue SJ, Lo PW, Huang FY, Cheng KW and Tung YL

Dye sensitized solar cells (DSSCs) containing 3-methoxypropionitrile (MPN) electrolyte solution are prepared by introducing microporous polycarbonate (PC) film supports of two pore sizes (nominal diameters of 0.2 and 0.05 μm). These PC films are stable up to 400°C. The conductivities of the PC films impregnated with the MPN electrolyte solution are not significantly different from each other. The DSSC efficiencies with and without the PC supports are compared under illumination intensities of 20, 50, and 100 mW cm-2. Under medium to strong light intensity, the control cell (without PC supports) has the highest photo-to-current efficiency, followed by those with the 0.2 and 0.05 μm PC supports. In the low intensity incident light, the cells with the 0.2 μm support slightly outperform the other cells. The control DSSCs and DSSCs containing PC supports are aged via light soaking at 60°C. The as-prepared and aged cells are analyzed using electrochemical impedance spectroscopy to isolate resistance components in the DSSCs. The cell efficiency is highly correlated with the reciprocal of serial resistance, which is the sum of the resistance values resulting from the platinum counter electrode, the ionic diffusion in the electrolyte, and the sheet resistance of the transparent conducting oxide. The resistance due to the ionic diffusion in the electrolyte is the most profound contributor to the serial resistance in the aged cells.