Soft-Photoconversion Using Floating Self-Assembled Crystalline Films of Porphyrin Nanostructures

One of many evolved functions of biological cell membranes is to induce and regulate self-assembly of photoactive molecules into efficient light harvesting nanomaterials. Synthetic molecular assemblies at soft interfaces exhibit macroscale long-range order and so provide routes to biomimetic analogues that minimise concentration quenching. Here, we report the facile assembly of free-standing layered crystalline films of zinc(II) meso-tetrakis(4-carboxyphenyl)porphyrin nanostructures that exhibit significant photocurrents in situ at an electrified liquid | liquid interface. This methodology does not require acidic conditions, specialised amphiphilic porphyrins, or the use of additives or external stimuli. The assembly process is driven by an interplay between the hydrophobicity gradient at an immiscible aqueous | organic interface and optimised hydrogen bonding in the formed nanostructure. Highly-ordered interfacial nanostructures may provide a new paradigm for realisation of light-harvesting antennae in artificial photosynthetic technologies.