Photosystem I From Higher Plants Enhances Electrode Performance

Abstract

INTERDISCIPLINARY MATERIALS SCIENCE PHOTOSYSTEM I FROM HIGHER PLANTS ENHANCE ELECTRODE PERFORMANCE DARLENE GUNTHER Thesis under the direction of Professor G. Kane Jennings Photosystem I (PSI) is a supramolecular protein complex found in the thylakoid membranes of higher plants, algae, and cyanobacteria. Recently, researchers from across the world have been interested in extracting PSI from its source and integrating it with electrodes to investigate biologically inspired solar energy conversion. There are two main investigations involving PSI in this thesis. First, adsorbing PSI monolayers onto atomically thin graphene creates a transparent, photoactive electrode that is less than 10 nm thick. Experiments utilizing PSI extracted from spinach and deposited onto graphene results in an enhanced photocurrent density over bare graphene electrodes. Furthermore, choice of opaque mediator with higher concentrations combined with highly transparent graphene produced larger photocurrents than the use of transparent mediator counterparts. Second, PSI is extracted from Pueraria lobata (kudzu) and deposited onto silicon electrodes for the first time. This study investigates the potential for transitioning from traditional food sources, such as spinach, to non-traditional food sources, such as kudzu, as a renewable resource for PSI. The kudzu-PSI-modified-silicon electrodes double the electrical output over bare silicon electrodes. Approved: G. Kane Jennings