Correlating structural assemblies of photosynthetic reaction centers on a gold electrode and the photocurrent - potential response
Daniel Jun,
Sylvester Zhang,
Adrian Jan Grzędowski,
Amita Mahey,
J. Thomas Beatty,
Dan Bizzotto
Affiliations
Daniel Jun
Advanced Materials and Process Engineering Laboratory, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
Sylvester Zhang
Advanced Materials and Process Engineering Laboratory, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
Adrian Jan Grzędowski
Advanced Materials and Process Engineering Laboratory, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
Amita Mahey
Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
J. Thomas Beatty
Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
Dan Bizzotto
Advanced Materials and Process Engineering Laboratory, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada; Corresponding author
Summary: The use of biomacromolecules is a nascent development in clean alternative energies. In applications of biosensors and biophotovoltaic devices, the bacterial photosynthetic reaction center (RC) is a protein-pigment complex that has been commonly interfaced with electrodes, in large part to take advantage of the long-lived and high efficiency of charge separation. We investigated assemblies of RCs on an electrode that range from monolayer to multilayers by measuring the photocurrent produced when illuminated by an intensity-modulated excitation light source. In addition, atomic force microscopy and modeling of the photocurrent with the Marcus-Hush-Chidsey theory detailed the reorganization energy for the electron transfer process, which also revealed changes in the RC local environment due to the adsorbed conformations. The local environment in which the RCs are embedded significantly influenced photocurrent generation, which has implications for electron transfer of other biomacromolecules deposited on a surface in sensor and photovoltaic applications employing a redox electrolyte.
