Light-Harvesting Nanomaterials Based on Dyes for Energy Transfer and Amplified Biosensing

Fascinating process of light harvesting (LH) in plants and bacteria leads to photosynthesis of oxygen and organic matter on the planet. It inspires researchers in the last decades to develop synthetic analogues - artificial LH nanomaterials. Here, LH nanomaterials based on dyes (organic chromophores) are reviewed. The fundamental aspects of LH include dye assembly into materials with minimal energy losses (i.e., high fluorescence quantum yield with minimized aggregation-caused quenching) and fast excitation energy transfer with large exciton migration length. The efficient energy transfer from LH nanomaterial to an acceptor leads to an amplification of acceptor emission - antenna effect, which constitutes the key performance parameter of LH nanoantenna. Individual classes of dye-based LH nanomaterials are analyzed: covalent molecular arrays of dyes (e.g., dendrimers and macrocycles), aggregates of "classical" dyes, aggregation-induced emission nanomaterials, metal-organic frameworks, ion-associated nanomaterials, and hybrid dye-based organic systems, such as dye-biomolecule hybrids, micelles and supramolecular polymers, dye-loaded silica and polymeric nanoparticles. The design principles and key performance characteristics of their selected (non-exhaustive) examples are analyzed. Due to their capacity to amplify the acceptor fluorescence signal, LH nanomaterials are particularly suitable for amplified sensing of small molecules, ions, biomolecules, which is particularly attractive for biomedical applications.