Rational Design of a Photosystem I Photoanode for the Fabrication of Biophotovoltaic Devices.

Photosystem I (PSI), a robust and abundant biomolecule capable of delivering high‐energy photoelectrons, has a great potential for the fabrication of light‐driven semi‐artificial bioelectrodes. Although possibilities have been explored in this regard, the true capabilities of this technology have not been achieved yet, particularly for their use as bioanodes. Here, the use of PSI Langmuir monolayers and their electrical wiring with specifically designed redox polymers is shown, ensuring an efficient mediated electron transfer as the basis for the fabrication of an advanced biophotoanode. The bioelectrode is rationally implemented and optimized for enabling the generation of substantial photocurrents of up to 17.6 µA cm−2 and is even capable of delivering photocurrents at potentials as low as −300 mV vs standard hydrogen electrode, surpassing the performance of comparable devices. To highlight the applicability of the developed light‐driven bioanode, a biophotovoltaic cell is assembled in combination with a gas‐breathing biocathode. The assembly operates in a single compartment cell and delivers considerable power outputs at large cell voltages. The implemented biophotoanode constitutes an important step toward the development of advanced biophotovoltaic devices. [ABSTRACT FROM AUTHOR]