Analysis of charge transport resistance of ZnO-based DSSCs because of the effect of different compression temperatures

Abstract

This article represents a research study about the effect of compression temperature on the performance of Zinc Oxide (ZnO)-based dye-sensitized solar cell (DSSC). To find the optimum compression temperature, the electrodeposited photoanodes are subjected to compression at 60 MP with various compression temperatures ranging from room temperature to 80 °C. The performance analysis involved the analysis of Electrochemical Impedance Spectroscopy (EIS) and photocurrent-voltage (I-V) data under dark and illuminated conditions. The EIS data are examined to gain insights into the electron transport mechanism and validate the cell's performance under optimum compression temperature. The findings of this study demonstrate that cells prepared at 60 MP with a compression temperature of 70 °C show the most favorable photovoltaic performance compared to cells prepared at other compression temperatures. Thickness measurement confirms that increasing the compression temperature ensures a compact layer of photoelectrode. A compression temperature greater than 70 °C causes several defects on the photoelectrode surface, as confirmed by the Scanning Electron Microscopy Image. EIS and I-V data confirm that the cell prepared at 60 MP and 70 °C heating gives comparatively lower series resistance and higher shunt resistance.  Though the series and shunt resistance exhibited different values under dark and illumination conditions, their trends remained consistent. Under this optimized compression temperature the cells achieved a maximum efficiency (η) of 2.78%, accompanied by an open circuit voltage (Voc) of 0.58 V, a photocurrent density (Jsc) of 8.87 mA/cm2, and a fill factor of 0.54.