Artificial Light-Harvesting System with Energy Migration Functionality in a Cationic Dye/Inorganic Nanosheet Complex

We investigated a reaction involving photochemical energy transfer between a cationic xanthene derivative (Flu(D)) and a cationic porphyrin (Por(A)) with an energy migration functionality, which is crucial for efficient light-harvesting on an inorganic nanosheet. Efficient energy transfer from excited Flu(D) to Por(A) took place, and the maximum energy transfer efficiency was 99%. Even under light-harvesting conditions, Por(A) concentration was much less than Flu(D) concentration (Flu(D)/Por(A) concentration ratio = 15), and the energy transfer efficiency was still 80%. Steady-state, time-resolved, anisotropic fluorescence measurements indicate energy migration between Flu(D) molecules. This system has the functionality of a light-harvesting system using a dye and having a large overlap between its absorption and fluorescence spectra.