Anion Effect on the Cu-Neocuproine Mediator and Its Electrocatalysts for Dye-Sensitized Solar Cells: Polymeric Chalcogenides of PEDOT-PEDTT and [Ag(SePh)].

The synthetical methodology for the [Cu(dmp)] (dmp = 2,9-dimethyl-1,10-phenanthroline; neocuproine) complexes has been systematically investigated by using various copper precursors, including CuCl, Cu(NO), and Cu(ClO). After an anion exchange to trifluoromethanesulfonimide (TFSI), the tetra-coordinated Cu(dmp)(TFSI)-Cu(ClO) (7.43%) outperformed the penta-coordinated Cu(dmp)(TFSI)(NO)-Cu(NO) (4.30%) and Cu(dmp)(TFSI)(Cl)-CuCl. Polymeric chalcogenides, including a conducting copolymeric electrode of PEDOT-PEDTT [PEDOT = poly(3,4-ethylenedioxythiophene); PEDTT = poly(3,4-ethylenedithiothiophene)] and a coordination polymeric electrode of silver bezeneselenolate ([Ag(SePh)]; mithrene), are introduced as the electrocatalysts for [Cu(dmp)] for the first time. After optimization, dye-sensitized solar cells (DSSCs) based on carbon cloth (CC)/AgSePh-30 (10.18%) showed superior electrocatalytic ability compared to the benchmark CC/Pt (7.43%) due to numerous active sites provided by electron-donating Se atoms, high film roughness, and bottom-up 2D charge transfer routes. The DSSC based on CC/PEDTT-50 (10.38%) also outperformed CC/Pt due to numerous active sites provided by electron-donating S atoms and proper energy band structure. This work sheds light on the future design and synthesis in Cu-complex mediators and functional polymeric chalcogenides for high-performance DSSCs.