| Photosynthetic chromophore analogs are studied, starting with simplified structures and systematically building complexity to elucidate overarching design principles. The general goals are to achieve an artificial light-harvesting system that exhibits broad spectral coverage, including extension well into the photon rich red and near-infrared portions of the solar spectrum. For example, the spectral properties of chlorophylls are primarily a consequence of the 131-oxophorbine base macrocycle, with further tuning provided by the dramatic difference in auxochromic effects of a given substituent at the 7- versus 3-position, consistent with Gouterman's four-orbital model.;While light-harvesting antennas in photosynthetic bacteria generally have near-quantitative transfer of excitation energy among pigments, only a fraction of the solar spectrum is typically absorbed. The new biohybrid antennas retain the energy-transfer and self-assembly characteristics of the native antenna complexes, offer enhanced coverage of the solar spectrum, and illustrate a versatile paradigm for the construction of artificial light-harvesting systems. Such complexes can ultimately connect with complimentary efforts in the realms of energy conversion and storage towards a successful utilization of natural and bio-inspired photosynthesis for energy production. |
