Chiral Conductive Polymers as Spin Filters

Mondal, Prakash Chandra; Kantor‐Uriel, Nirit; Mathew, S. P.; Tassinari, Francesco; Fontanesi, Claudio; Naaman, Ron

doi:10.1002/adma.201405249

Cited by 136 publications

(115 citation statements)

References 26 publications

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“…Thus, we developed a method to reduce the oxide film on Ni in situ with the assembly of a monolayer of chiral polymer. 43 We grafted the polymer film on the Ni surface via electrochemical reduction, scanning the potential in the −0.1 to −0.8 V range vs saturated calomel electrode (SCE); the l -isomer of the chiral polymer, poly{[methyl N -(tert-butoxycarbonyl)- S -3-thienyl- l -cysteinate]-cothiophene} (PCT-L, Figure 2) forms a helical supramolecular structure via intermolecular H-bonding and π stacking among the thiophene rings. The PCT-L film (∼3 nm thick) was characterized by a number of different methods, including CD measurements, PMIRRAS, solid state magnetoresistance measurements, and enantioselectivity in the voltammetric response in the presence of a chiral ferrocene derivative.…”

Section: Spin Filtering Through Chiral Conductive Polymermentioning

confidence: 99%

Section: Spin Filtering Through Chiral Conductive Polymermentioning

confidence: 99%

Section: Spin Filtering Through Chiral Conductive Polymermentioning

confidence: 99%

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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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Section: Spin Filtering Through Chiral Conductive Polymermentioning

confidence: 99%

Section: Spin Filtering Through Chiral Conductive Polymermentioning

confidence: 99%

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

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“…The CISS effect relates to the ability of chiral molecules to transmit electrons in a spin-selective manner, hence the molecules act as spin filters. 6,7 Several chiral molecular species including DNA, [8][9][10][11][12] oligopeptides, [13][14][15] bacteriorhodopsin (bR), 16,17 a chiral conductive polymer, 18 1, 2-diphenyl-1,2-ethanediol (DPED), 19 helicenes, 20 and recently chiral CdSe quantum dots 21 have demonstrated efficient spin filtering. The spin filtering ability can be tuned by various means, for example, by varying the length of the chiral molecule, 8,9,13 by exposure to light, 22 or by varying the temperature.…”

Section: Introductionmentioning

confidence: 99%

Structure dependent spin selectivity in electron transport through oligopeptides

Kiran

Cohen

Naaman

2016

The Journal of Chemical Physics

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108

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The chiral-induced spin selectivity (CISS) effect entails spin-selective electron transmission through chiral molecules. In the present study, the spin filtering ability of chiral, helical oligopeptide monolayers of two different lengths is demonstrated using magnetic conductive probe atomic force microscopy. Spin-specific nanoscale electron transport studies elucidate that the spin polarization is higher for 14-mer oligopeptides than that of the 10-mer. We also show that the spin filtering ability can be tuned by changing the tip-loading force applied on the molecules. The spin selectivity decreases with increasing applied force, an effect attributed to the increased ratio of radius to pitch of the helix upon compression and increased tilt angles between the molecular axis and the surface normal. The method applied here provides new insights into the parameters controlling the CISS effect. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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“…Chirality occurs at the molecular level as enantiomers of an asymmetric carbon centred molecule and at the supramolecular level, on different length-scales2, from asymmetric structural arrangements, such as helices. In the last decades, chirality has been extended to applications in non-linear optics3 and more recently in spintronics45. These applications aim to combine the specific optical properties of chirality with the advantage of a supramolecular approach.…”

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Spatial control of chirality in supramolecular aggregates

Castriciano

Gentili

Romeo

et al. 2017

Sci Rep

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Chirality is one of the most intriguing properties of matter related to a molecule’s lack of mirror symmetry. The transmission of chirality from the molecular level up to the macroscopic scale has major implications in life sciences but it is also relevant for many chemical applications ranging from catalysis to spintronic. These technological applications require an accurate control of morphology, homogeneity and chiral handedness of thin films and nanostructures. We demonstrate a simple approach to specifically transfer chirality to the model supramolecular system of J aggregates of the protonated form of tetrakis(4-sulfonatophenyl)-porphyrin by utilizing a soft lithography technique. This approach successfully allows the fabrication of an ordered distribution of sub-micrometric structures in precise and controllable positions with programmed chirality, providing a fundamental breakthrough toward the exploitation of chiral supramolecular aggregates in technological applications, such as sensors, non-linear optics and spintronic.

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Chiral Conductive Polymers as Spin Filters

Cited by 136 publications

References 26 publications

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

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

Structure dependent spin selectivity in electron transport through oligopeptides

Spatial control of chirality in supramolecular aggregates

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