Photosystem i (PSI)/Photosystem II (PSII)-based photo-bioelectrochemical cells revealing directional generation of photocurrents

Omer Yehezkeli, Ran Tel-Vered, Dorit Michaeli, Rachel Nechushtai, Itamar Willner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

98 Scopus citations


Layered assemblies of photosystem I, PSI, and/or photosystem II, PSII, on ITO electrodes are constructed using a layer-by-layer deposition process, where poly N,N′-dibenzyl-4,4′-bipyridinium (poly-benzyl viologen, PBV 2+) is used as an inter-protein "glue". While the layered assembly of PSI generates an anodic photocurrent only in the presence of a sacrificial electron donor system, such as dichlorophenol indophenol (DCPIP)/ascorbate, the PSII-modified electrode leads, upon irradiation, to the formation of an anodic photocurrent (while evolving oxygen), in the absence of any sacrificial component. The photocurrent is generated by transferring the electrons from the PSII units to the PBV2+ redox polymer. The charge-separated species allow, then, the injection of the electrons to the electrode, with the concomitant evolution of O2. A layered assembly, consisting of a PSI layer attached to a layer of PSII by the redox polymer PBV2+, leads to an anodic photocurrent that is 2-fold higher, as compared to the anodic photocurrent generated by a PSII-modified electrode. This observation is attributed to an enhanced charge separation in the two-photosystem assembly. By the further nano-engineering of the two photosystems on the electrode using two different redox polymers, vectorial electron transfer to the electrode is demonstrated, resulting in a ca. 6-fold enhancement in the photocurrent. The reversed bi-layer assembly, consisting of a PSII layer linked to a layer of PSI by the PBV2+ redox polymer, yields, upon irradiation, an inefficient cathodic current. This observation is attributed to a mixture of photoinduced electron transfer reactions of opposing effects on the photocurrent directions in the two-photosystem assembly.

Original languageAmerican English
Pages (from-to)2970-2978
Number of pages9
Issue number17
StatePublished - 9 Sep 2013


  • electrodes
  • photocurrents
  • photoelectrochemistry
  • photosystems
  • redox polymers


Dive into the research topics of 'Photosystem i (PSI)/Photosystem II (PSII)-based photo-bioelectrochemical cells revealing directional generation of photocurrents'. Together they form a unique fingerprint.

Cite this