Novel Amphiphilic Ruthenium Sensitizer with Hydrophobic Thiophene or Thieno(3,2-b)thiophene-Substituted 2,2 '-Dipyridylamine Ligands for Effective Nanocrystalline Dye Sensitized Solar Cells

Abstract

Hydrophobic conjugated 2,2'-dipyridylamine Substituted amphiphilic ruthenium complexes {cis-Ru(dcbpy)(L)(NCS)(2), where dcbpy is 4,4'-dicarboxylic acid-2,2'-bipyridine and L is 4,4'-di(5-hexylthiophen-2-yl)-2,2'-dipyridylamine, JK-85, or 4,4'-di[5-hexylthieno(3,2-b)thiophene]-2,2'-dipyridylamine, JK-86} were newly designed, synthesized, and successfully used as sensitizers for nanocrystalline dye sensitized solar cell using an electrolyte consisting of 0.6 M 1,2-dimethyl-3-propylimiidazolium iodide (DMPII), 0.05 M I-2, 0.1 M LiI, and 0.5 M tert-butylpyridine in acetonitrile. Under standard AM 1.5 sunlight, the complex JK-86 yielded a short-circuit photocurrent density of 18.3 mA/cm(2), an open-circuit voltage of 0.68 V, and a fill factor of 0.72, corresponding to an overall conversion efficiency of 9.03%. Importantly, the cell exhibits an excellent stability, revealing almost no change after 1000 h of light soaking at 60 degrees C using a quasi-so lid-state electrolyte composed of 0.1 M h, 0.5 M NMBI (n-methylbenzimidazole), 0.6 M DMPII (1-propyl-2,3-dimethylimidazolium iodide), and 5 wt % PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)) in MPN (3-methoxypropionitrile).