Influence of Iodide Concentration on the Efficiency and Stability of Dye-Sensitized Solar Cell Containing Non-Volatile Electrolyte

Dye-sensitized solar cells based on nanocrystalline TiO2 have been fabricated with an amphiphilic ruthenium sensitizer NaRu(4-carboxylic acid-4'-carboxylate) (4,4'-dinonyl-2,2'-bipyridine)(NCS)2, coded as Z-907Na, and a series of non-volatile 3-methoxyproprionitrile (MPN)-based electrolytes with different concentration of 1-methyl-3-propylimidazolium iodide (PMII). The short-circuit photocurrent density increases with increasing iodide concentration until at 1.5M practically quantitative dye regeneration is achieved as proved by time-resolved laser experiments. Devices containing 1.0M PMII electrolyte show excellent stability during long-time thermal aging at 80 degrees C and under light soaking at 60 degrees C.