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Photospintronics: Magnetic Field-Controlled Photoemission and Light-Controlled Spin Transport in Hybrid Chiral Oligopeptide-Nanoparticle Structures.

Mondal PC, Roy P, Kim D, Fullerton EE, Cohen H, Naaman R - Nano Lett. (2016)

Bottom Line: It is shown here that in systems in which organic molecules and semiconductor nanoparticles are combined, matching these technologies results in interesting new phenomena.We report on light induced and spin-dependent charge transfer process through helical oligopeptide-CdSe nanoparticles' (NPs) architectures deposited on ferromagnetic substrates with small coercive force (∼100-200 Oe).By switching the direction of the magnetic field of the substrate, the PL intensity could be alternated.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel.

ABSTRACT
The combination of photonics and spintronics opens new ways to transfer and process information. It is shown here that in systems in which organic molecules and semiconductor nanoparticles are combined, matching these technologies results in interesting new phenomena. We report on light induced and spin-dependent charge transfer process through helical oligopeptide-CdSe nanoparticles' (NPs) architectures deposited on ferromagnetic substrates with small coercive force (∼100-200 Oe). The spin control is achieved by the application of the chirality-induced spin-dependent electron transfer effect and is probed by two different methods: spin-controlled electrochemichemistry and photoluminescence (PL) at room temperature. The injected spin could be controlled by excitation of the nanoparticles. By switching the direction of the magnetic field of the substrate, the PL intensity could be alternated.

No MeSH data available.


Chronoamperometric measurements (current versustime) for (A) Ala8 and (B) Ala8–CdSe structures on a magneticcobalt working electrode in the presence of an external static magneticfield either pointing UP (solid blue line) or DOWN (solid red line)in a Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9. The samples were illuminatedwith a green laser having a 514 nm wavelength. Magnetic field-dependentcurrent versus time measurements were recorded at +0.32 V (oxidationprocess) and 0 V (reduction process) versus a saturated calomel electrode(SCE).
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fig4: Chronoamperometric measurements (current versustime) for (A) Ala8 and (B) Ala8–CdSe structures on a magneticcobalt working electrode in the presence of an external static magneticfield either pointing UP (solid blue line) or DOWN (solid red line)in a Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9. The samples were illuminatedwith a green laser having a 514 nm wavelength. Magnetic field-dependentcurrent versus time measurements were recorded at +0.32 V (oxidationprocess) and 0 V (reduction process) versus a saturated calomel electrode(SCE).

Mentions: To verify theobservations, we performed chronoamperometry experiments in whichthe current at a given potential is recorded as a function of time.The electron conduction across the SAMs (of Ala8) themselves and throughilluminated oligopeptide–CdSe structures was measured (Figure 4A,B, respectively).Whereas for the SAMs themselves or for the SAM–CdSe NPs inthe dark (data not shown), the Faradaic current was higher when themagnet was pointing DOWN; however, in the illuminated sample the currentwas higher when the magnetic field direction was pointing UP. Thiseffect was observed for both the oxidation or reduction processes.For the chiral SAMs, only when the SAM–CdSe NPs were in thedark the SP was +17 ± 1% and +35 ± 2% at 0.32 and 0 V, respectively.When the SAM–CdSe NP sample was illuminated at 514 nm, theSP is −11 ± 1% at +0.32 V, and −30 ± 2% atthe reduction potential, 0 V. The voltammograms recorded on a bareferromagnetic substrate as a working electrode did not exhibit anymagnetic field effect on the Faradaic current when the working electrodewas magnetized either with its magnetic moment pointing UP or DOWN(Figure S8).


Photospintronics: Magnetic Field-Controlled Photoemission and Light-Controlled Spin Transport in Hybrid Chiral Oligopeptide-Nanoparticle Structures.

Mondal PC, Roy P, Kim D, Fullerton EE, Cohen H, Naaman R - Nano Lett. (2016)

Chronoamperometric measurements (current versustime) for (A) Ala8 and (B) Ala8–CdSe structures on a magneticcobalt working electrode in the presence of an external static magneticfield either pointing UP (solid blue line) or DOWN (solid red line)in a Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9. The samples were illuminatedwith a green laser having a 514 nm wavelength. Magnetic field-dependentcurrent versus time measurements were recorded at +0.32 V (oxidationprocess) and 0 V (reduction process) versus a saturated calomel electrode(SCE).
© Copyright Policy
Related In: Results  -  Collection

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fig4: Chronoamperometric measurements (current versustime) for (A) Ala8 and (B) Ala8–CdSe structures on a magneticcobalt working electrode in the presence of an external static magneticfield either pointing UP (solid blue line) or DOWN (solid red line)in a Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9. The samples were illuminatedwith a green laser having a 514 nm wavelength. Magnetic field-dependentcurrent versus time measurements were recorded at +0.32 V (oxidationprocess) and 0 V (reduction process) versus a saturated calomel electrode(SCE).
Mentions: To verify theobservations, we performed chronoamperometry experiments in whichthe current at a given potential is recorded as a function of time.The electron conduction across the SAMs (of Ala8) themselves and throughilluminated oligopeptide–CdSe structures was measured (Figure 4A,B, respectively).Whereas for the SAMs themselves or for the SAM–CdSe NPs inthe dark (data not shown), the Faradaic current was higher when themagnet was pointing DOWN; however, in the illuminated sample the currentwas higher when the magnetic field direction was pointing UP. Thiseffect was observed for both the oxidation or reduction processes.For the chiral SAMs, only when the SAM–CdSe NPs were in thedark the SP was +17 ± 1% and +35 ± 2% at 0.32 and 0 V, respectively.When the SAM–CdSe NP sample was illuminated at 514 nm, theSP is −11 ± 1% at +0.32 V, and −30 ± 2% atthe reduction potential, 0 V. The voltammograms recorded on a bareferromagnetic substrate as a working electrode did not exhibit anymagnetic field effect on the Faradaic current when the working electrodewas magnetized either with its magnetic moment pointing UP or DOWN(Figure S8).

Bottom Line: It is shown here that in systems in which organic molecules and semiconductor nanoparticles are combined, matching these technologies results in interesting new phenomena.We report on light induced and spin-dependent charge transfer process through helical oligopeptide-CdSe nanoparticles' (NPs) architectures deposited on ferromagnetic substrates with small coercive force (∼100-200 Oe).By switching the direction of the magnetic field of the substrate, the PL intensity could be alternated.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel.

ABSTRACT
The combination of photonics and spintronics opens new ways to transfer and process information. It is shown here that in systems in which organic molecules and semiconductor nanoparticles are combined, matching these technologies results in interesting new phenomena. We report on light induced and spin-dependent charge transfer process through helical oligopeptide-CdSe nanoparticles' (NPs) architectures deposited on ferromagnetic substrates with small coercive force (∼100-200 Oe). The spin control is achieved by the application of the chirality-induced spin-dependent electron transfer effect and is probed by two different methods: spin-controlled electrochemichemistry and photoluminescence (PL) at room temperature. The injected spin could be controlled by excitation of the nanoparticles. By switching the direction of the magnetic field of the substrate, the PL intensity could be alternated.

No MeSH data available.