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′-bipyri-dine)(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 1.5 m practically quantitative dye regeneration is achieved as proved by time-resolved laser experiments. Devices containing 1.0 m PMII electrolyte show excellent stability during long-time thermal aging at 80°C and under light soaking at 60°C.