title: Electrochemical switching of photoelectrochemical processes at CdS QDs and photosystem I-modified electrodes.
abstract: 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.
authors.affiliation: Department of Plant Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Ariel
authors.initials: A
authors.lastname: Efrati
authors.forename: Omer
authors.initials: O
authors.lastname: Yehezkeli
authors.forename: Ran
authors.initials: R
authors.lastname: Tel-Vered
authors.forename: Dorit
authors.initials: D
authors.lastname: Michaeli
authors.forename: Rachel
authors.initials: R
authors.lastname: Nechushtai
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry* / Q000528:radiation effects*; D004566:Electrodes; D004574:Electromagnetic Fields; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage; D018036:Selenium Compounds / Q000737:chemistry* / Q000528:radiation effects*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*
chemical_list: D019187:Cadmium Compounds; D045331:Photosystem I Protein Complex; D018036:Selenium Compounds; C058667:cadmium selenide