Long-range energy propagation in nanometer arrays of light harvesting antenna complexes.

Here we report the first observation of long-range transport of excitation energy within a biomimetic molecular nanoarray constructed from LH2 antenna complexes from Rhodobacter sphaeroides. Fluorescence microscopy of the emission of light after local excitation with a diffraction-limited light beam reveals long-range transport of excitation energy over micrometer distances, which is much larger than required in the parent bacterial system. The transport was established from the influence of active energy-guiding layers on the observed fluorescence emission. We speculate that such an extent of energy migration occurs as a result of efficient coupling between many hundreds of LH2 molecules. These results demonstrate the potential for long-range energy propagation in hybrid systems composed of natural light harvesting antenna molecules from photosynthetic organisms.