Investigation of Dye Concentration Variations and Their Impact on Dye‐Sensitized Solar Cell Efficiency

ABSTRACT This study investigates the dye concentration dependent study on the performance of dye‐sensitized solar cells (DSSCs) by examining key characterization techniques, including UV‐Vis, IR, Raman, EIS, J‐V measurements and J‐t transient analysis. Increasing dye concentration enhances light absorption, as observed through UV‐Vis spectra, leading to an initial increase in J sc in the J‐V measurements. However, beyond an optimal concentration, excessive dye loading leads to aggregation and a reduction in electron injection efficiency, as evidenced by an increase in charge transfer resistance in the EIS spectra. This also results in increased recombination and reduced fill factor, ultimately lowering the overall conversion efficiency. The J‐t analysis further reveals that higher dye concentrations slow the current stabilization and cause faster decay rates due to higher recombination. Optimal dye concentrations strike a balance between light absorption, electron injection, and recombination, resulting in high efficiency and stable performance. The highest efficiency (1.1%) is achieved with a moderate concentration of 0.1 mM of mercurochrome dye.