Supramolecular Solar Cells: Surface Modification of Nanocrytalline TiO_2 with Coordinating Ligands To Immobilize Sensitizers and Dyads via Metal-Ligand Coordination for Enhanced Photocurrent Generation

摘要

In nature, self-assembly through noncovalent binding motifs, such as hydrogen bonding, metal-ligand coordination, and electrostatic, π-π, and weak van der Waals interactions, plays a dominant role. For example, photosynthetic antenna reaction center pigments use such intermolecular forces to precisely arrange the donor-acceptor entities in a protein matrix, exhibiting a cascade of vectorial energy and .alectron transfer processes. Inspired by this revelation, several groups have constructed supramolecular photosynthetic architectures to mimic the photoinduced energy and electron transfer processes, with an ultimate goal of building efficient light-energy-harvesting devices based on these biomimetic principles. Solar cells baseG on biomimetic principles could serve as an alternative to semiconductor-based ones for renewable energy production. Here, the design and construction of electron- and hole-transporting nanostructured architectures are pivotal for enhancing both charge separation efficiency and charge carrier mobility to improve the photovoltaic response. Although donor-acceptor-type dyads have frequently been utilized for this purpose, examples employing noncovalent methodologies, especially the highly versatile metal-ligand binding approach for assembling the different entities on the electrode surface, have been scarce.