Abstract
A new ion-coordinating ruthenium polypyridyl sensitizer, NaRu(4-carboxylic acid-4'-carboxylate)(4,4'-bis[(triethyleneglycolmethylether) heptylether]-2,2'-bipyridine)(NCS)(2) (coded as K68), has been synthesized and characterized by H-1 NMR, FTIR, UV-Vis absorption and emission spectroscopy. A power conversion efficiency of 6.6% was obtained for dye-sensitized solar cells (DSCs) based on the K68 dye and a newly developed binary ionic liquid electrolyte containing 1-propyl-3-methyl-imidazolium iodide (PMII) and 1-ethyl-3-methyl- imidazolium tetracyanoborate (EMIB(CN)(4)). For a non-volatile organic solvent based electrolyte, a photovoltaic power conversion efficiency of 7.7% was obtained under simulated full sun light and exhibited a good thermal stability during the accelerated test under 80 degrees C in the dark. Solid-state DSCs incorporating K68 also perform remarkably well, out-performing our previously best ruthenium complexes employed in this type of DSC. (c) 2007 Elsevier B.V. All rights reserved.