Luminescence quenching behavior of [Ru(bpy)2(dppz)]2+-DNA/CdS/ITO electrode controlled synchronically by copper(II) ion and external electric field

• Ru(II) complex-intercalated DNA film is assembled on CdS/ITO electrode.
• Hybrid electrode shows tunable luminescence by external electric field and Cu2+.
• Photoluminescence and photovoltaic response are synchronously decreased by Cu2+.
• Synergistic effects of luminescence quenching and photovoltage shift are discussed.

A [Ru(bpy)2(dppz)]2+-intercalated DNA film (bpy = 2,2′-bipyridine and dppz = dipyrido[3,2-a:2′,3′-c]phenazine) is successfully assembled on an indium-tin oxide (ITO) electrode modified with CdS nanoparticles, designated as Ru(II)-DNA/CdS/ITO electrode. In the present protocol, [Ru(bpy)2(dppz)]2+ intercalated in the DNA film has contributed characteristic photoluminescence properties to the Ru(II)-DNA/CdS/ITO electrode, in which CdS nanoparticles can bestow the tunable photovoltaic response. The as-prepared electrode shows a very consistent luminescence quenching by both applied anodic potentials and Cu(II) ions, which can extract the electrons from Ru(II)-based excited states (λEx = 450 nm). The photo-sensitive Ru(II)-DNA/CdS/ITO electrode is able to gain a maximum negative shift of ca. 0.467 V (open-circuit photovoltage vs. Ag/AgCl, 0.05 M NaCl) upon irradiation with UV–vis light between 350 and 700 nm. Additionally, the photovoltaic response including open-circuit photovoltage and short-circuit photocurrent for Ru(II)-DNA/CdS/ITO electrode (vs. Ag/AgCl) is also weakened by Cu(II) ions, indicating a synergistic effect with photoluminescence quenching. The preliminary results show a new approach to synchronically control the photoluminescence and photovoltaic response of DNA-metallointercalators and nanoconductor particles through the introduction of chemical agents, as well as open the way for optoelectronic switches.

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