title: A ZnO nanowire bio-hybrid solar cell.
abstract: Harvesting solar energy as a carbon free source can be a promising solution to the energy crisis and environmental pollution. Biophotovoltaics seek to mimic photosynthesis to harvest solar energy and to take advantage of the low material costs, negative carbon footprint, and material abundance. In the current study, we report on a combination of zinc oxide (ZnO) nanowires with monolayers of photosynthetic reaction centers which are self-assembled, via a cytochrome c linker, as photoactive electrode. In a three-probe biophotovoltaics cell, a photocurrent density of 5.5 μA cm-2and photovoltage of 36 mV was achieved, using methyl viologen as a redox mediator in the electrolyte. Using ferrocene as a redox mediator a transient photocurrent density of 8.0 μA cm-2was obtained, which stabilized at 6.4 μA cm-2after 20 s. In-depth electronic structure characterization using photoemission spectroscopy in conjunction with electrochemical analysis suggests that the fabricated photoactive electrode can provide a proper electronic path for electron transport all the way from the conduction band of the ZnO nanowires, through the protein linker to the RC, and ultimately via redox mediator to the counter electrode.
authors.affiliation: Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA.
authors.forename: Houman
authors.initials: H
authors.lastname: Yaghoubi
authors.forename: Michael
authors.initials: M
authors.lastname: Schaefer
authors.forename: Shayan
authors.initials: S
authors.lastname: Yaghoubi
authors.forename: Daniel
authors.initials: D
authors.lastname: Jun
authors.forename: Rudy
authors.initials: R
authors.lastname: Schlaf
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Beatty
authors.forename: Arash
authors.initials: A
authors.lastname: Takshi