Filling the Green Gap of a Megadalton Photosystem I Complex by Conjugation of Organic Dyes

Photosynthesis is Natur&s major process for converting solar into chemical energy. One of the key players' in this process is the multiprotein complex photosystem I (PSI) that through absorption of incident,photons enables electron transfer, which makes this, protein attractive for applications in bioinspired photoactive hybrid materials. However, the efficiency of PSI is still limited by its poor absorption in the green part of the solar spectrum. Inspired by the existence of natural phycobilisome light-harvesting antennae, we have widened the absorption spectrum of PSI by covalent attachment of synthetic dyes to the protein backbone. Steady-state and time-resolved photoluminescence reveal that energy transfer occurs from these dyes to PSI. It is shown by oxygen consumption measurements that subsequent charge generation is subtantially enhanced :under broad and, narrow band excitation., Ultiniately surface photovoltage (SPV) experiments prove the enhanced. activity of dye-Modified PSI even in the. solid State.