Limits...
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.


Related in: MedlinePlus

Spin-dependentcyclic voltammograms recorded for (A) Ala8 monolayers adsorbed overferromagnetic substrates, (B) Ala8–CdSe hybrid structures underdark conditions, and (C) under light conditions. The voltammogramswere obtained when the ferromagnetic cobalt (used as the working electrode)is magnetized either with its magnetic moment pointing UP (the solidblue line), or pointing DOWN (the solid red line). Voltammograms wererecorded in Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9 at a scan rate of 50mV s–1, keeping the area of the ferromagnetic workingelectrode the same in all cases.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4834632&req=5

fig3: Spin-dependentcyclic voltammograms recorded for (A) Ala8 monolayers adsorbed overferromagnetic substrates, (B) Ala8–CdSe hybrid structures underdark conditions, and (C) under light conditions. The voltammogramswere obtained when the ferromagnetic cobalt (used as the working electrode)is magnetized either with its magnetic moment pointing UP (the solidblue line), or pointing DOWN (the solid red line). Voltammograms wererecorded in Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9 at a scan rate of 50mV s–1, keeping the area of the ferromagnetic workingelectrode the same in all cases.

Mentions: Spin-dependent electrochemical measurements were performedusing both the oligopeptide and oligopeptide-NP structures assembledon the ferromagnetic substrates in the presence of a chemically robustredox probe such as K4[Fe(CN)6]/K3[Fe(CN)6] in tris(hydroxymethyl)aminomethane) (TRIS) buffer(see Figure 1B). TheSAM-modified ferromagnetic substrate was used as the working electrode(WE), platinum wire as the counter electrode (CE), and a KCl-saturatedcalomel electrode as the reference electrode (RE). A permanent magnethaving a field of 0.35 T was placed underneath the ferromagnetic workingelectrode, which can be flipped by changing its direction by 180°so that the magnetic field points either toward the surface (UP) oraway from it (DOWN). The NPs in the hybrid structures could be excitedat 514 nm during the electron conduction measurements. The dependenceof the CV curves on the direction of the magnetic field and on theillumination is shown in Figure 3. In the dark, the substrate was coated only with theSAM (Figure 3A) andone was coated both with SAM and NPs (Figure 3B); both show magnetic field-dependent CVcurves with a higher current when the magnet points DOWN. The spinpolarization (SP) is defined as , where I(V)↓ and I(V)↑ represent the currentsobtained through monolayers with the magnetic field pointing “DOWN”or “UP”, respectively, at a specific applied potential(V). The SP for transmission through the chiral Ala8 monolayers is+11 ± 1% at +50 mV and +7 ± 0.5% at +0.32 V. These valuesare similar to those obtained before with different chiral molecules.10,22


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)

Spin-dependentcyclic voltammograms recorded for (A) Ala8 monolayers adsorbed overferromagnetic substrates, (B) Ala8–CdSe hybrid structures underdark conditions, and (C) under light conditions. The voltammogramswere obtained when the ferromagnetic cobalt (used as the working electrode)is magnetized either with its magnetic moment pointing UP (the solidblue line), or pointing DOWN (the solid red line). Voltammograms wererecorded in Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9 at a scan rate of 50mV s–1, keeping the area of the ferromagnetic workingelectrode the same in all cases.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834632&req=5

fig3: Spin-dependentcyclic voltammograms recorded for (A) Ala8 monolayers adsorbed overferromagnetic substrates, (B) Ala8–CdSe hybrid structures underdark conditions, and (C) under light conditions. The voltammogramswere obtained when the ferromagnetic cobalt (used as the working electrode)is magnetized either with its magnetic moment pointing UP (the solidblue line), or pointing DOWN (the solid red line). Voltammograms wererecorded in Tris buffer containing 5 mM K4[Fe(CN)6]/K3[Fe(CN)6] at pH 9 at a scan rate of 50mV s–1, keeping the area of the ferromagnetic workingelectrode the same in all cases.
Mentions: Spin-dependent electrochemical measurements were performedusing both the oligopeptide and oligopeptide-NP structures assembledon the ferromagnetic substrates in the presence of a chemically robustredox probe such as K4[Fe(CN)6]/K3[Fe(CN)6] in tris(hydroxymethyl)aminomethane) (TRIS) buffer(see Figure 1B). TheSAM-modified ferromagnetic substrate was used as the working electrode(WE), platinum wire as the counter electrode (CE), and a KCl-saturatedcalomel electrode as the reference electrode (RE). A permanent magnethaving a field of 0.35 T was placed underneath the ferromagnetic workingelectrode, which can be flipped by changing its direction by 180°so that the magnetic field points either toward the surface (UP) oraway from it (DOWN). The NPs in the hybrid structures could be excitedat 514 nm during the electron conduction measurements. The dependenceof the CV curves on the direction of the magnetic field and on theillumination is shown in Figure 3. In the dark, the substrate was coated only with theSAM (Figure 3A) andone was coated both with SAM and NPs (Figure 3B); both show magnetic field-dependent CVcurves with a higher current when the magnet points DOWN. The spinpolarization (SP) is defined as , where I(V)↓ and I(V)↑ represent the currentsobtained through monolayers with the magnetic field pointing “DOWN”or “UP”, respectively, at a specific applied potential(V). The SP for transmission through the chiral Ala8 monolayers is+11 ± 1% at +50 mV and +7 ± 0.5% at +0.32 V. These valuesare similar to those obtained before with different chiral molecules.10,22

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.


Related in: MedlinePlus