Electrochemical switching of photoelectrochemical processes at CdS QDs and photosystem I-modified electrodes

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Photoactive inorganic CdS quantum dots (QDs) or the native photosystem I (PSI) is immobilized onto a pyrroloquinoline quinone (PQQ) monolayer linked to Au electrodes to yield hybrid relay/QDs (or photosystem) assemblies. By the electrochemical biasing of the electrode potential, the relay units are retained in their oxidized PQQ or reduced PQQH 2 states. The oxidized or reduced states of the relay units dictate the direction of the photocurrent (anodic or cathodic). By the cyclic biasing of the electrode potential between the values E ≥ -0.05 V and E ≤ -0.3 V vs Ag quasi-reference electrode (Ag QRE), retaining the relay units in the oxidized PQQ or reduced PQQH 2 states, the photocurrents are respectively switched between anodic and cathodic values. Different configurations of electrically switchable photoelectrochemical systems are described: (i) the PQQ/CdS QDs/(triethanolamine, TEOA) or PQQ/PSI/(ascorbic acid/dichlorophenolindophenol, DCPIP) systems, leading to anodic photocurrents; (ii) the PQQ/CdS QDs (or PSI)/(flavin adenine dinucleotide) systems, leading to cathodic photocurrents; (iii) the PQQ/CdS QDs (or PSI)/(O 2) switchable systems, leading to cyclic anodic/cathodic switching of the photocurrents.

Original languageAmerican English
Pages (from-to)9258-9266
Number of pages9
JournalACS Nano
Issue number10
StatePublished - 23 Oct 2012


  • electrochemical switching
  • modified electrode
  • photocurrent
  • photoelectrochemistry
  • photosystem
  • quantum dots
  • switch


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