Heteroleptic Ruthenium(II) Complexes with 2,2 ́- Bipyridines Having Carbonitriles as Anchoring Groups for ZnO Surfaces: Syntheses, Physicochemical Properties and Applications in Organic Solar Cells

SALOMÓN, FERNANDO F.; VEGA, NADIA C.; JURADO, JOSÉ PIERS; MORÁN VIEYRA, FAUSTINO EDUARDO; TIRADO, MÓNICA; COMEDI, DAVID; CAMPOY-QUILES, MARIANO; CATTANEO, MAURICIO; KATZ, NÉSTOR E.

INORGANIC CHEMISTRY

AMER CHEMICAL SOC

Año: 2021 vol. 60 p. 5660 - 5672

0020-1669

Heteroleptic ruthenium (II) complexes were used for sensitizing ZnO surfaces in organic solar cells (OSCs) as mediators with photoactive layers. The complexes [Ru(4,4 ́-X2-bpy)(Mebpy-CN)2]2+ (with X = -CH3, -OCH3 and -N(CH3)2; bpy = 2,2 ́-bipyridine; Mebpy-CN = 4-methyl-2,2 ́-bipyridine-4 ́-carbonitrile) were synthesized and studied by analytical and spectroscopical techniques. Spectroscopic, photophysical, and electrochemical properties were tuned by changing the electron-donating ability of the -X substituents at the 4,4 ́-positions of the bpy ring and rationalized by quantum-mechanical calculations. These complexes were attached through nitrile groups to ZnO as interfacial layer in an OSC device with a PBDB-T:ITIC photoactive layer. This modified inorganic electron transport layer generates enhancement in photo-conversion of the solar cells, reaching up to 23% increment with respect to the unsensitized OSCs. The introduction of these dyes suppresses some degradative reactions of the non-fullerene acceptor due to the photocatalytic activity of zinc oxide, which was maintained stable for about 11 months. Improving OSCs efficiencies and stabilities can thus be achieved by a judicious combination of new inorganic and organic materials.