Anion\nEffect on the Cu<sup>II</sup>–Neocuproine\nMediator and Its Electrocatalysts for Dye-Sensitized Solar Cells:\nPolymeric Chalcogenides of PEDOT–PEDTT and [Ag<sub>2</sub>(SePh)<sub>2</sub>]<sub><i>

The\nsynthetical methodology for the [Cu(dmp)<sub>2</sub>]<sup>2+/1+</sup> (dmp = 2,9-dimethyl-1,10-phenanthroline; neocuproine)\ncomplexes has been systematically investigated by using various copper\nprecursors, including CuCl<sub>2</sub>, Cu(NO<sub>3</sub>)<sub>2</sub>, and Cu(ClO<sub>4</sub>)<sub>2</sub>. After an anion exchange to\ntrifluoromethanesulfonimide (TFSI), the tetra-coordinated Cu<sup>II</sup>(dmp)<sub>2</sub>(TFSI)<sub>2</sub>-Cu(ClO<sub>4</sub>)<sub>2</sub> (7.43%) outperformed the penta-coordinated Cu<sup>II</sup>(dmp)<sub>2</sub>(TFSI)(NO<sub>3</sub>)-Cu(NO<sub>3</sub>)<sub>2</sub> (4.30%)\nand Cu<sup>II</sup>(dmp)<sub>2</sub>(TFSI)(Cl)-CuCl<sub>2</sub>. Polymeric\nchalcogenides, including a conducting copolymeric electrode of PEDOT–PEDTT\n[PEDOT = poly(3,4-ethylenedioxythiophene); PEDTT = poly(3,4-ethylenedithiothiophene)]\nand a coordination polymeric electrode of silver bezeneselenolate\n([Ag<sub>2</sub>(SePh)<sub>2</sub>]<sub><i>n</i></sub>;\nmithrene), are introduced as the electrocatalysts for [Cu(dmp)<sub>2</sub>]<sup>2+/1+</sup> for the first time. After optimization,\ndye-sensitized solar cells (DSSCs) based on carbon cloth (CC)/AgSePh-30\n(10.18%) showed superior electrocatalytic ability compared to the\nbenchmark CC/Pt (7.43%) due to numerous active sites provided by electron-donating\nSe atoms, high film roughness, and bottom-up 2D charge transfer routes.\nThe DSSC based on CC/PEDTT-50 (10.38%) also outperformed CC/Pt due\nto numerous active sites provided by electron-donating S atoms and\nproper energy band structure. This work sheds light on the future\ndesign and synthesis in Cu-complex mediators and functional polymeric\nchalcogenides for high-performance DSSCs.