Light-Controlled Spin Filtering in Bacteriorhodopsin

Einati, Hila; Mishra, Debabrata; Friedman, Noga; Sheves, Mordechai; Naaman, Ron

doi:10.1021/nl503961p

Cited by 45 publications

(61 citation statements)

References 25 publications

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“…49 Note that both for the wild bR and the mutant, the preferred spin direction (higher faradaic current) was observed when the modified nickel was magnetized in the “UP” direction.…”

Section: Light Controlled Spin Filtering Across the Bacteriorhodopsinmentioning

confidence: 97%

Spin-Dependent Transport through Chiral Molecules Studied by Spin-Dependent Electrochemistry

et al. 2016

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ConspectusMolecular spintronics (spin + electronics), which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call “chiral-induced spin selectivity” (CISS). In this Account, we discuss new types of spin-dependent electrochemistry measurements and their use to probe the spin-dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR), and oligopeptide-CdSe nanoparticles (NPs) hybrid structures. Spin-dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing “UP” or “DOWN” using a permanent magnet (H = 0.5 T), placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5–30%, even in the case of small chiral molecules. Chiral films of the l- and d-cysteine tethered with a redox-active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to “dark” measurements, we also describe photoelectrochemical measurements in which light is used to affect the spin selective electron transport through the chiral molecules. We describe how the excitation of a chromophore (such as CdSe nanoparticles), which is attached to a chiral working electrode, can flip the preferred spin orientation of the photocurrent, when measured under the identical conditions. Thus, chirality-induced spin polarization, when combined with light and magnetic field effects, opens new avenues for the study of the spin transport properties of chiral molecules and biomolecules and for creating new types of spintronic devices in which light and molecular chirality provide new functions and properties.

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“…49 Note that both for the wild bR and the mutant, the preferred spin direction (higher faradaic current) was observed when the modified nickel was magnetized in the “UP” direction.…”

Section: Light Controlled Spin Filtering Across the Bacteriorhodopsinmentioning

confidence: 97%

Spin-Dependent Transport through Chiral Molecules Studied by Spin-Dependent Electrochemistry

et al. 2016

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“…This system has been previously suggested as a candidate for bio‐electronics, and in a former study, wild‐type bR was shown to have spin‐filtering properties . Spin‐dependent electrochemical studies were conducted on purple membrane containing a mutant of bacteriorhodopsin (bR) adsorbed on nickel substrates . The bR protein is embedded in its native membrane environment, resembling most closely its natural structure.…”

Section: The Ciss Effectmentioning

confidence: 99%

Chirality – Beyond the Structural Effects

Naaman

2016

Israel Journal of Chemistry

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Usually, when one refers to chirality, one focuses on the structural properties of the molecules. This review focuses on the interesting electronic properties of these molecules, and specifically, on the interrelation between the spin of the electrons transmitted through molecules and the chiral structure of these molecules. This relation is expressed in the chiral‐induced spin selectivity (CISS) effect, which is described, including some of its implications. Specifically, several applications are described, in spintronics, in spin‐specific reactivity, and in spin‐controlled multiple‐electron oxidation processes. In the latter, experimental results are described that demonstrate that by coating the anode of a photoelectrochemical cell with chiral molecules, the overpotential of the water‐splitting process can be reduced.

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“…There are plenty of materials to be conjugated with bR. As an example, according to the reports on light-controlled spin filtering in bR [89], magnetic nanoparticles such as nickel and iron oxide can be an area of interest for further research.…”

Section: Summary and Perspectivesmentioning

confidence: 99%