Exploring Structure-Property Relationships in a Family of Ferrocene-Containing, Triphenylamine-Based Hybrid Organic Dyes

Abstract

In this work, a new family of triphenylamine-based dyes equipped with ferrocene (Fc)-containing donors have been synthesized, characterized, and studied within dye-sensitized solar cells (DSSC). With the objective of designing a redox-robust iron-containing dye that effectively sensitizes titania, a family of five structurally related dyes containing ferrocene were prepared. The physicochemical properties of all dyestuffs were studied using UV-Vis and electrochemical measurements. Different cross-coupling strategies resulted in the ability to modestly tune the Fc/Fc+ redox potentials of the dye. Despite the Fc-containing dyes having optoelectronic properties consistent with the non-ferrocene parent dye, the performance of the dyes in devices was dismal and decreased with the number of appended ferrocenes. While this finding was consistent with previous attempts to explore Fc-TPA DSSC dyes, our spectroelectrochemical data supports the hypothesis that the ferrocene component of the dye is oxidized by the electrolyte, ultimately decreasing the dye’s ability to be a suitable sensitizer. While these dyes are not suitable for DSSC applications, they might find applications in other photo-induced integrated devices where charge recombination is minimal.