Design and fabrication of a series of metal-mediated assemblies with tetrapyridylporphyrins for supramolecular solar cells

In this work, a metal-mediated assembling strategy has been used to organize a series of new assemblies based on tetrapyridylporphyrin (ZnP) on nanostructured TiO₂ electrode surfaces, wherein the metal ions (M, M = Zn²⁺, Cd²⁺, Hg²⁺ and Mn²⁺) bridge the pyridyl units of ZnP and (E)-4-[(pyridin-4-ylmethylene)-amino]benzoic acid (A), resulting in a ZnP-M-A assembled mode. The assembled structures were characterized by transmission electron microscopy (TEM), computational calculations, energy-dispersive X-ray spectroscopy (EDX), IR, UV-vis absorption and fluorescence spectra. The performances of the assembly-sensitized solar cells were also measured under an irradiance of 100 mW cm^-2 AM 1.5G sunlight. Photoelectrochemical results reveal a relatively large photocurrent of the ZnP-Mn-A device. Simultaneously, a large open-circuit photovoltage and a significantly improved conversion efficiency of the ZnP-Zn-A device are also observed. These findings may serve as another good testing ground for the fabrication of supramolecular solar cells in future.