Ruthenium(ii)-polypyridyl zirconium(iv) metal-organic frameworks as a new class of sensitized solar cellsElectronic supplementary information (ESI) available: PXRD, TGA, BET, SEM, emission lifetimes, diffuse reflectance, steady state emission, and IPCE/diffuse reflectance overlay. See DOI: 10.1039/c5sc01565k

A series of Ru( ii )L 2 L′ (L = 2,2′-bipyridyl, L′ = 2,2′-bipyridine-5,5′-dicarboxylic acid), RuDCBPY, -containing zirconium( iv ) coordination polymer thin films have been prepared as sensitizing materials for solar cell applications. These metal-organic framework (MOF) sensitized solar cells, MOFSCs, each are shown to generate photocurrent in response to simulated 1 sun illumination. Emission lifetime measurements indicate the excited state quenching of RuDCBPY at the MOF-TiO 2 interface is extremely efficient (>90%), presumably due to electron injection into TiO 2 . A mechanism is proposed in which RuDCBPY-centers photo-excited within the MOF-bulk undergo isotropic energy migration up to 25 nm from the point of origin. This work represents the first example in which a MOFSC is directly compared to the constituent dye adsorbed on TiO 2 (DSC). Importantly, the MOFSCs outperformed their RuDCBPY-TiO 2 DSC counterpart under the conditions used here and, thus, are solidified as promising solar cell platforms. Ruthenium( ii ) polypyridyl-doped metal-organic framework sensitized films on TiO 2 for photovoltaics reveal that the preparative method of dye doping/incorporation into the MOF is integral to the total solar cell efficiency.