Electrochemical Switching of Photoelectrochemical Processes at CdS QDs and Photosystem I-Modified Electrodes

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• 作者：Ariel Efrati ; Omer Yehezkeli ; Ran Tel-Vered ; Dorit Michaeli ; Rachel Nechushtai ; Itamar Willner
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：October 23, 2012
• 年：2012
• 卷：6
• 期：10
• 页码：9258-9266
• 全文大小：469K
• 年卷期：v.6,no.10(October 23, 2012)
• ISSN：1936-086X

文摘

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 PQQH₂ 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 鈮?鈭?.05 V and E 鈮?鈭?.3 V vs Ag quasi-reference electrode (Ag QRE), retaining the relay units in the oxidized PQQ or reduced PQQH₂ 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)/(O₂) switchable systems, leading to cyclic anodic/cathodic switching of the photocurrents.

Keywords:

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