Anion Effect on the Cu^II–Neocuproine Mediator and Its Electrocatalysts for Dye-Sensitized Solar Cells: Polymeric Chalcogenides of PEDOT–PEDTT and [Ag₂(SePh)₂]_n

The synthetical methodology for the [Cu(dmp) 2 ] 2+/1+ (dmp = 2,9-dimethyl-1,10-phenanthroline; neocuproine) complexes has been systematically investigated by using various copper precursors, including CuCl 2, Cu(NO 3 ) 2, and Cu(ClO 4 ) 2 . After an anion exchange to trifluoromethanesulfonimide (TFSI), the tetra-coordinated Cu II (dmp) 2 (TFSI) 2 -Cu(ClO 4 ) 2 (7.43%) outperformed the penta-coordinated Cu II (dmp) 2 (TFSI)(NO 3 )-Cu(NO 3 ) 2 (4.30%) and Cu II (dmp) 2 (TFSI)(Cl)-CuCl 2 . 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 2 (SePh) 2 ] n; mithrene), are introduced as the electrocatalysts for [Cu(dmp) 2 ] 2+/1+ 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.