Unraveling the Synergistic Effects of Thiazolidine Co‐Sensitizers in Dye‐Sensitized Solar Cells

ABSTRACT Dye‐sensitized solar cells (DSSCs) have garnered significant attention as a promising photovoltaic technology because of their low cost and simplicity. However, the development of efficient organic sensitizers remains a challenge. In this study, we report the synthesis and characterization of two novel organic co‐sensitizers, CD‐1 and TD‐2 , based on a thiazolidine core structure and the incorporation of carbazole and triphenylamine donor moieties, respectively. Co‐sensitizers were designed to leverage the strong electron‐donating abilities of these donors to facilitate efficient light‐harvesting and charge‐transfer processes. In‐depth analyses of the spectroscopic and electrochemical properties provided insights into the characteristics of TD‐2 compared with those of CD‐1 . TD‐2 displayed a wider range of absorption wavelengths, a narrower energy gap (2.19 eV), and a higher energy level for its (HOMO) than that of CD‐1 . These distinctions are attributed to the enhanced capacity of TD‐2 to donate electrons and the elongated π‐conjugation of the triphenylamine component. Upon sensitization, the TD‐2 scored efficiency reached 5.10% and co‐sensitized with N719 dye achieved the highest efficiency, reaching 7.95%. Both sensitizers increased the efficiency of N719 by co‐sensitization ( TD‐2 + N719 ), with an efficiency higher than 15% compared with N719 .