کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4753784 | 1417591 | 2017 | 9 صفحه PDF | دانلود رایگان |
- Interactions of disulfide/thiolate redox mediator with Z907 dye are studied.
- One thiolate anion cannot regenerate Z907+ completely through one-step mechanism.
- Two thiolate anions can regenerate Z907+ completely via two-step mechanism like Iâ.
- Unfound Z907-disulfide complex supports the slower recombination process in DSSC.
The intermolecular interactions of thiolate anions and disulfide molecules as disulfide/thiolate (T2/Tâ, S2/Sâ) redox couples with a Ru bipyridyl complex (Z907) are investigated using density functional theory. T and S are 1-methyl-1H-tetrazole-5-thiolate and 2-methyl-5-trifluoromethyl-2H-1,2,4-triazole-3-thiolate, respectively. Similar to the typical reductant Iâ, the S atoms of thiolate anions interact with the oxidized Z907 (Z907+) via the terminal S atoms of the isothiocyanate (NCS) ligands. However, nearly 40% of the atomic charge and spin still remain after complexation. If a second thiolate anion, as well as Iâ, is considered, the atomic charge and spin are transferred completely. The distances of the formed SS bonds for the Z907+-two anions species correspond to isolated dithiolate radicals. These results suggest that Z907+ can be completely regenerated by two thiolate anions via a two-step mechanism rather than by only one thiolate anion through a one-step mechanism as previously suggested. Unlike the I2 molecule, the unfound Z907-disulfide complex structure supports the slower recombination process with the disulfide/thiolate electrolyte compared with the I3â/Iâ system in dye-sensitized solar cells.
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 349, 1 December 2017, Pages 207-215