Solid‐State Biophotovoltaic Cells Containing Photosystem I

Abstract

The large multiprotein complex, photosystem I (PSI), which is at the heart of light-dependent reactions in photosynthesis, is integrated as the active component in a solid-state organic photovoltaic cell. These experiments demonstrate that photoactive megadalton protein complexes are compatible with solution processing of organic-semiconductor materials and operate in a dry non-natural environment that is very different from the biological membrane.

Orientation and Incorporation of Photosystem I in Bioelectronics Devices Enabled by Phage Display

“…This is the same orientation afforded by the PD‐selected peptides. The same orientation was confirmed on ITO using DHAP as short linker molecule by comparing with data from biophotovoltaic devices incorporating PSI 22. In contrast, the opposite orientation, which is accessible with director SAMs of thiolates, gives rise to the opposite asymmetry.…”

“…In this orientation, the photogenerated electrons of PSI are predominantly injected into the metal oxide. Moreover, there are significant differences between the peptides P1–P3 and scrambled ALF peptide compared to the small directing molecule DHAP 22. For the normal cells (with the low work function LiF/Al top electrode) incorporating DHAP, Δ V OC was 0.03 V, while for all directing peptides a Δ V OC greater than 0.1 V was obtained (Table S2, Supporting Information).…”

“…The process of light harvesting and charge separation is very efficient, with an internal quantum efficiency close to unity. For that reason, PSI complexes have been incorporated into bio‐photonic devices, biosolar and biofuel cells 20, 21, 22, 23. Further improvements serving the purpose of photocurrent generation were achieved by implanting Pt nanocrystals in PSI and the fabrication of a nanocomposite by electropolymerization of thioaniline on electrode surfaces 24.…”

“…In comparison to macroscopic studies, the ITO surface was functionalized with an SAM of DHAP as described elsewhere 22. The EGaIn measurement protocol is described in detail separately 26.…”

“…We chose BHJ solar cells containing PSI as electrode modifiers because these devices may act as a biophysical tool to determine the influence of the orientation of PSI in functional devices under illumination 22. In this way, we extend the characterization of the near‐perfect orientation of SAMs of PSI by peptides selected by PD and demonstrate that they retain their function/orientation in standard sandwich‐device architectures.…”