Schiff Base Ancillary Ligands in Bis(diimine) Copper(I) Dye-Sensitized Solar Cells

International Journal of Molecular Sciences

Elias Lüthi¹  Alessandro Prescimone¹  EdwinC. Constable¹  PaolaAndrea Forero Cortés¹  CatherineE. Housecroft¹ 

[1] Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland;

关键词: copper;    dye-sensitized solar cell;    schiff base;    phosphonic acid;    crystal structure;   

DOI  :  10.3390/ijms21051735

来源: DOAJ

【 摘 要 】

Five 6,6′-dimethyl-2,2′-bipyridine ligands bearing N-arylmethaniminyl substituents in the 4- and 4′-positions were prepared by Schiff base condensation in which the aryl group is Ph (1), 4-tolyl (2), 4-^tBuC₆H₄ (3), 4-MeOC₆H₄ (4), and 4-Me₂NC₆H₄ (5). The homoleptic copper(I) complexes [CuL₂][PF₆] (L = 1−5) were synthesized and characterized, and the single crystal structure of [Cu(1)₂][PF₆]·Et₂O was determined. By using the “surfaces-as-ligands, surfaces-as-complexes” (SALSAC) approach, the heteroleptic complexes [Cu(6)(L_ancillary)]⁺ in which 6 is the anchoring ligand ((6,6′-dimethyl-[2,2′-bipyridine]-4,4′-diyl)bis(4,1-phenylene))bis(phosphonic acid)) and L_ancillary = 1−5 were assembled on FTO-TiO₂ electrodes and incorporated as dyes into n-type dye-sensitized solar cells (DSCs). Data from triplicate, fully-masked DSCs for each dye revealed that the best-performing sensitizer is [Cu(6)(1)]⁺, which exhibits photoconversion efficiencies (η) of up to 1.51% compared to 5.74% for the standard reference dye N719. The introduction of the electron-donating MeO and Me₂N groups (L_ancillary = 4 and 5) is detrimental, leading to a decrease in the short-circuit current densities and external quantum efficiencies of the solar cells. In addition, a significant loss in open-circuit voltage is observed for DSCs sensitized with [Cu(6)(5)]⁺, which contributes to low values of η for this dye. Comparisons between performances of DSCs containing [Cu(6)(1)]⁺ and [Cu(6)(4)]⁺ with those sensitized by analogous dyes lacking the imine bond indicate that the latter prevents efficient electron transfer across the dye.

【 授权许可】

Unknown