title: Tris(2-(1H-pyrazol-1-yl)pyridine)cobalt(III) as p-type dopant for organic semiconductors and its application in highly efficient solid-state dye-sensitized solar cells.
abstract: Chemical doping is an important strategy to alter the charge-transport properties of both molecular and polymeric organic semiconductors that find widespread application in organic electronic devices. We report on the use of a new class of Co(III) complexes as p-type dopants for triarylamine-based hole conductors such as spiro-MeOTAD and their application in solid-state dye-sensitized solar cells (ssDSCs). We show that the proposed compounds fulfill the requirements for this application and that the discussed strategy is promising for tuning the conductivity of spiro-MeOTAD in ssDSCs, without having to rely on the commonly employed photo-doping. By using a recently developed high molar extinction coefficient organic D-π-A sensitizer and p-doped spiro-MeOTAD as hole conductor, we achieved a record power conversion efficiency of 7.2%, measured under standard solar conditions (AM1.5G, 100 mW cm(-2)). We expect these promising new dopants to find widespread applications in organic electronics in general and photovoltaics in particular.
authors.affiliation: Laboratoire de Photoniques et Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Station 6, 1015 Lausanne, Switzerland.
authors.forename: Julian
authors.initials: J
authors.lastname: Burschka
authors.forename: Amalie
authors.initials: A
authors.lastname: Dualeh
authors.forename: Florian
authors.initials: F
authors.lastname: Kessler
authors.forename: Etienne
authors.initials: E
authors.lastname: Baranoff
authors.forename: Ngoc-Lê
authors.initials: NL
authors.lastname: Cevey-Ha
authors.forename: Chenyi
authors.initials: C
authors.lastname: Yi
authors.forename: Mohammad K
authors.initials: MK
authors.lastname: Nazeeruddin
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D011211:Electric Power Supplies; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D012666:Semiconductors; D012993:Solar Energy
chemical_list: D004396:Coloring Agents; D009942:Organometallic Compounds; C570414:tris(2-(1H-pyrazol-1-yl)pyridine)cobalt(III)