Enhancing photovoltaic efficiency with SQI-Br and SQI-I sensitizers: A comparative analysis

This study investigates the use of halogen bonding to enhance the effectiveness of short-circuit current density (J(SC)) in dye-sensitized solar cells (DSSCs). To improve the performance of DSSCs, two dyes, SQI-Br and SQI-I, based on halogen atom-functionalized unsymmetrical squaraine dyes, were designed. These dyes were tested in DSSCs using iodolyte electrolytes (Z-50 and Z-100), and their performance was further improved by the introduction of chenodesoxycholic acid (CDCA). While both dyes exhibited unique photovoltaic characteristics without CDCA, a significant improvement was observed when three equivalents of CDCA were added. The most favorable results were achieved with the SQI-I dye, three equivalents of CDCA, and iodolyte Z-100, resulting in an efficiency of 6.74%, V-OC of 0.694 V, and a short-circuit current density of 13.67 mA/cm(2) of DSSCs. This enhanced performance can be attributed to the presence of a sigma-hole, which strengthens the interaction between the electrolyte and the dyes on the TiO2 substrate, thereby facilitating dye regeneration.