Ultrafast Spintronics: Dynamics of the Photoisomerization-Induced Spin–Charge Excited-State (PISCES) Mechanism in Spirooxazine-Based Photomagnetic Materials

Jenkins, Adam J.; Mao, Ziliang; Kurimoto, Aiko; Mix, L. Tyler; Frank, Natia L.; Larsen, Delmar S.

doi:10.1021/acs.jpclett.8b02166

Cited by 5 publications

(3 citation statements)

References 45 publications

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“…Quantum yields for the photochromic conversion of MC to SO are generally much lower than those for the SO-to-MC conversion. The mechanism of the photoinduced ring closure of MC has been studied by ultrafast spectroscopy. , Bifurcation through an unknown and short-lived excited state intermediate occurs, such that the majority of the photoproduct funnels back to the open MC form, leading to low quantum yields for the generation of the closed SO form (1–2% typically). The value of Φ MCSO determined here is thus consistent with known properties of merocyanines.…”

Section: Results and Discussionmentioning

confidence: 99%

Controlling Photoswitching via pcFRET in Conjugated Polymer Nanoparticles

et al. 2018

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Nanoparticles prepared from conjugated polymers (CPNs or Pdots) are powerful fluorophores for sensing and imaging applications, including those that require fluorescence photoswitching. We and others have developed CPNs doped with photochromic dyes that act as acceptors in only one of their two forms via fluorescence resonance energy transfer (pcFRET). We recently developed visible-light-responsive CPNs doped with a reverse photochromic spirooxazine dye that has a thermally stable merocyanine form. Off-to-on fluorescence switching occurs when the merocyanine is switched to its nonquenching spirooxazine form. The on-state fluorescence intensity is more than 100 times greater when photoswitching occurs via FRET from the CPNs than when the dyes are excited directly. Temporal control of fluorescence intensity is achieved using a single-color input of variable intensity for fluorescence excitation (read-only mode) and photoswitching (read–write mode). Here, we present photokinetic measurements and simulations that establish the origin of the observed fluorescence behavior. We find that highly efficient CPN-to-merocyanine energy transfer sensitizes the photochromic reaction, which has a quantum yield of 0.03 in the absence of FRET. Simulated fluorescence trajectories reveal that the low photochromic quantum yield is the necessary condition for single-color intensity control in this system. From the simulations, we determine that the product of the photochromic quantum yield and the energy transfer efficiency (Φ × E) must be no more than 0.05 to produce analogous fluorescence behavior. These findings suggest that the CPNs could be used as an amplifier to drive other low-quantum-yield photoreactions to completion with intensity control.

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Section: Results and Discussionmentioning

confidence: 99%

Controlling Photoswitching via pcFRET in Conjugated Polymer Nanoparticles

et al. 2018

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“…Instead of using Fe(II) or Ni(II) spin state switching, photochromic organic ligands can be involved in the formation of Co(III) complexes revealing an electron transfer phenomenon. , Such an idea was realized by N. L. Frank and co-workers by assembling spiro(azahomoadamantyl-phenanthrolinoxazine) ligand (apso), Co(II) centers, and an o -benzoquinone (dtbq, Figure ). The open form of apso ligand favors the LS Co(III) state, thus the formation of a radical on one of the benzoquinone anions.…”

Section: Photoswitching Of Molecule-based Magnetic Materialsmentioning

confidence: 99%

Optical Phenomena in Molecule-Based Magnetic Materials

Zakrzewski,

Liberka,

Wang

et al. 2024

Chem. Rev.

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Since the last century, we have witnessed the development of molecular magnetism which deals with magnetic materials based on molecular species, i.e., organic radicals and metal complexes. Among them, the broadest attention was devoted to molecule-based ferro-/ferrimagnets, spin transition materials, including those exploring electron transfer, molecular nanomagnets, such as single-molecule magnets (SMMs), molecular qubits, and stimuli-responsive magnetic materials. Their physical properties open the application horizons in sensors, data storage, spintronics, and quantum computation. It was found that various optical phenomena, such as thermochromism, photoswitching of magnetic and optical characteristics, luminescence, nonlinear optical and chiroptical effects, as well as optical responsivity to external stimuli, can be implemented into molecule-based magnetic materials. Moreover, the fruitful interactions of these optical effects with magnetism in molecule-based materials can provide new physical cross-effects and multifunctionality, enriching the applications in optical, electronic, and magnetic devices. This Review aims to show the scope of optical phenomena generated in molecule-based magnetic materials, including the recent advances in such areas as high-temperature photomagnetism, optical thermometry utilizing SMMs, optical addressability of molecular qubits, magneto-chiral dichroism, and opto-magneto-electric multifunctionality. These findings are discussed in the context of the types of optical phenomena accessible for various classes of molecule-based magnetic materials.

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“…Pulsed magnetic fields could provide ultrafast switching, but exceed present technologies, for example, requiring sub-picosecond pulsed magnetic fields of >35 Tesla [6]. Light-induced spin state switching [7,8,9,10] has been demonstrated, but the need to dissipate the energy absorbed from optical photons would limit the throughput of such devices [11,12].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Basis for Switching a Kramers Single Molecular Magnet by Circularly-Polarized Radiation

et al. 2019

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The d-group Kramers ions, having strong zero field splitting (ZFS) with axial symmetry and a negative D value for the ZFS Hamiltonian, are widely considered as candidates for use as single molecular magnets (SMMs). An important need is the means to switch the SMM between its states in a reasonably short and predictable period of time, which is generally not available. We propose an approach, Zeeman–far infrared (ZeFIR) double resonance, in which circularly polarized alternating magnetic fields in the far infrared (FIR) range induce selective magnetic dipole transitions between different Kramers doublets of the SMM and polarized microwave (mw) pulses transfer excitation inside the upper Kramers doublet. A combination of FIR and mw pulses allows unidirectional switching between +S and −S states of the ion. The proposed approach is considered for a model quartet system with total spin S = 3/2, which seems to be the most promising object for selective resonance manipulations of its states by circularly polarized radiation.

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Ultrafast Spintronics: Dynamics of the Photoisomerization-Induced Spin–Charge Excited-State (PISCES) Mechanism in Spirooxazine-Based Photomagnetic Materials

Cited by 5 publications

References 45 publications

Controlling Photoswitching via pcFRET in Conjugated Polymer Nanoparticles

Controlling Photoswitching via pcFRET in Conjugated Polymer Nanoparticles

Optical Phenomena in Molecule-Based Magnetic Materials

Theoretical Basis for Switching a Kramers Single Molecular Magnet by Circularly-Polarized Radiation

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