Nanostructured TiO₂ modified with acetohydrazide zinc porphyrin well-arrays for supramolecular solar cells

In this work, employing the metal-mediated assembling strategy for organizing acetohydrazide zinc porphyrin (ZnP) and different organic acid (Ai) ligands on the nanostructured TiO₂ electrode surfaces have been prepared, wherein the ZnP and Ai units are bound by a series of differently bivalent metal ions (M, M = Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺ and Hg²⁺), resulting in a ZnP-M-Ai assembled approach. The photovoltaic performances of these assemblies-sensitized solar cells were performed under irradiance of 100 mW cm^-2 AM 1.5G sunlight. A significantly improved conversion efficiency of ZnP-Mn-A5 and ZnP-Cd-A5 devices occurs, indicating well-ordered arrangements of ZnP molecules on the TiO₂ electrode surfaces for ZnP-Mn-A5 and ZnP-Cd-A5, where A5 is a pyridine-monocarboxylic acid ligand bearing longer arm. The results were also verified by the HOMO-LUMO gaps, UV-vis and fluorescence spectra.