Photoelectrochemical properties of dyads composed of porphyrin/ruthenium catalyst grafted on metal oxide semiconductors

In the current work, we present the use of two free-base and two zinc-metallated porphyrin-ruthenium(II) polypyridine dyads, along with two reference porphyrin derivatives, as sensitizers in both n- and p-type DSSCs and DSPECs. Two of the dyads contain the well-known Ru(bpy)3 unit (HOOC-DMP-Ru(bpy)3 and HOOC-(Zn)DMP-Ru(bpy)3), while in the other two terpyridine-Ru(Cl)-bypiridine was used (HOOC-DMP-tpy-Ru and HOOC-(Zn)DMP-tpy-Ru). In all systems, the amide-bonding motif was utilized for the connection of the counterparts comprising each dyad. Photophysical investigation of the reported systems indicated sufficient electronic interactions for the dyads in their excited states (emission measurements). The photovoltaic measurements revealed that the presence of the ruthenium complex improves the overall performance of the dyads with the most efficient dyad being HOOC-(Zn)DMP-tpy-Ru in both n- and p-type DSSCs. Consequently, HOOC-(Zn)DMP-tpy-Ru was used to fabricate n- and p-DSPECs towards the oxidation of methoxy-benzyl alcohol and the reduction of CO2, respectively.