title: Charge separation and efficient light energy conversion in sensitized mesoscopic solar cells based on binary ionic liquids.
abstract: A 7.4% power conversion efficiency at air mass (AM) 1.5 full sunlight was reached with a mesoscopic solar cell employing a new binary ionic liquid electrolyte composed of 1-propyl-3-methylimidazolium iodide and 1-ethyl-3-methylimidazolium tricyanomethanide in conjunction with the amphiphilic ruthenium complex NaRu(4-carboxylic acid-4'-carboxylate)(4,4'-dinonyl-2,2'-bipyridine)(NCS)(2), coded as Z-907Na. Ultramicroelectrode voltammetric, nanosecond laser transient absorbance, and photovoltaic measurements show that a high iodide concentration is required for dye regeneration to compete efficiently with charge recombination. A surprisingly fast reductive quenching process is turned on in pure iodide melts. This channel is unproductive, explaining the lower photocurrents observed under these conditions.
authors.affiliation: Laboratory for Photonics and Interfaces, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Bernard
authors.initials: B
authors.lastname: Wenger
authors.forename: Robin
authors.initials: R
authors.lastname: Humphry-Baker
authors.forename: Jacques-E
authors.initials: JE
authors.lastname: Moser
authors.forename: Joël
authors.initials: J
authors.lastname: Teuscher
authors.forename: Willi
authors.initials: W
authors.lastname: Kantlehner
authors.forename: Jochen
authors.initials: J
authors.lastname: Mezger
authors.forename: Edmont V
authors.initials: EV
authors.lastname: Stoyanov
authors.forename: Shaik M
authors.initials: SM
authors.lastname: Zakeeruddin
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel