scholarly journals Magnetic field effect on exciplex-forming organic acceptor/donor system: a powerful tool for understanding the preferential solvation

2016 ◽  
Vol 19 (3) ◽  
pp. 65-75
Author(s):  
Hao Minh Hoang ◽  
Van Thi Bich Pham
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Preferential Solvation ◽  
Magnetic Field Effect ◽  
Solvation Shell ◽  
Dielectric Constants ◽  
Binary Solvents ◽  
Charge Transfer Complexes ◽  
Solvent Mixtures ◽  
Magnetic Field Effects

Many acceptor/donor systems can form excited-state charge-transfer complexes (exciplexes) in photo-induced electron transfer reactions. Exciplex can be detected by their luminescence. In addition, the exciplex luminescence is magneto-sensitive. Here, we employ an approach based on the magnetic field effect on the exciplex of 9,10- dimethylanthracene/N,N-dimethylaniline pair in micro-homogeneous and micro-heterogeneous binary solvents to investigate the effects of the preferential solvation processes on solute molecules in solutions. Micro-homogeneous solvent mixtures of propyl acetate (PA)/butyronitrile (BN) allow for a systematic variation of the static dielectric constants, s , in the range from 6.0 to 24.6. The mixtures of toluene (TO)/dimethylsulfoxide (DMSO) with varying the s values in the range from 4.3 to 15.5 are used as micro-heterogeneous binary solvents. In micro-heterogeneous environment, DMSO molecules get preferentially favoured in the solvation shell, forming micro-clusters surrounding the solute molecules. This solvation effect is reflected in the altered magnetic field effects, lifetimes and dissociation rate constants of the exciplexes.

scholarly journals Development of Lock-in Based Overtone Modulated MARY Spectroscopy for Detection of Weak Magnetic Field Effects

2020 ◽  
Author(s):  
Marcin Konowalczyk ◽  
Olivia Foster Vander Elst ◽  
Jonathan Storey
Keyword(s):  
Magnetic Field ◽  
Weak Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Reaction Yield ◽  
Magnetic Field Effects ◽  
Detection Scheme ◽  
Natural Isotopic Abundance ◽  
Field Effects ◽  
High Modulation

Modulated magnetically altered reaction yield (ModMARY) spectroscopy is a derivative variant of fluorescence detected magnetic field effect measurement, where the applied magnetic field has both a constant and a modulated component. As in many derivative spectroscopy techniques, the signal to noise ratio scales with the magnitude of the modulation. High modulation amplitudes, however, distort the signal and can obscure small features of the measured spectrum. In order to detect weak magnetic field effects (including the low field effect) a balance of the two has to be found. In this work we look in depth at the origin of the distortion of the MARY signal by field modulation. We then present an overtone detection scheme, as well as a data analysis method which allows for correct fitting of both harmonic and overtone signals of the modulation broadened MARY data. This allows us to robustly reconstruct the underlying MARY curve at different modulation depths. To illustrate the usefulness of the technique, we show measurements and analysis of a well known magnetosensitive system of pyrene / 1,3-dicyanobenzene (Py/DCB). The measurements of first (h1) and second (h2) harmonic spectra are performed at different modulation depths for both natural isotopic abundance, and perdeuterated pyrene samples.<br>

Time Resolved Magnetic Field Effects as a Probe for Geminate Recombination

1976 ◽  
Vol 31 (5) ◽  
pp. 499-500 ◽  
Author(s):  
R. Haberkorn ◽  
M. E. Midiel-Beyerle
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Theoretical Description ◽  
Transfer Reactions ◽  
Geminate Recombination ◽  
Magnetic Field Effects ◽  
Time Resolved ◽  
Transient Spectroscopy ◽  
The Magnetic Field

Abstract A theoretical description for the magnetic field dependence of geminate recombination as observed in transient spectroscopy of electron transfer reactions, is given and applications of this novel magnetic field effect are discussed.

scholarly journals The Origin of SO2 Afterglows as Revealed by Magnetic Field Effects

1994 ◽  
Vol 13 (3-4) ◽  
pp. 223-239 ◽  
Author(s):  
Haruo Abe
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Strength ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Magnetic Field Effects ◽  
Chemiluminescence Intensity ◽  
Pressure Diffusion ◽  
Strength Dependence ◽  
The Magnetic Field

The chemiluminescence intensity in the low pressure diffusion flame of the CS2 + O/N2 system was found to be considerably affected by external magnetic fields. The emitter in the flame was identified as the main emitter in the SO2 afterglow. The measurements of the field strength dependence, collisional effect, and spectral distribution of the magnetic field effect revealed the major emitter as the SO2 in the C˜ state. External magnetic fields were also found to quench fluorescence remarkably emitted from the vibronic levels just below the predissociation threshold in the C˜ state. From the observed vibrational-level, field-strength, and pressure dependences of the magnetic quenching, it became evident that the major emitter of chemiluminescence in the flame could be assigned to the SO2 molecule in the vibronic levels located at about 800 cm–1 below the predissociation threshold in the C˜ state

scholarly journals Simple rules for resolved level-crossing spectra in magnetic field effects on reaction yields

2021 ◽  
Vol 2 (1) ◽  
pp. 77-91
Author(s):  
Dmitri V. Stass ◽  
Victor A. Bagryansky ◽  
Yuri N. Molin
Keyword(s):  
Magnetic Field ◽  
Electron Spin Resonance ◽  
Field Effect ◽  
Radical Pair ◽  
Magnetic Field Effect ◽  
Magnetic Field Effects ◽  
Level Crossing ◽  
Spin Resonance ◽  
Simple Rules ◽  
Effect Curve

Abstract. In this work we derive conditions under which a level-crossing line in a magnetic field effect curve for a recombining radical pair will be equivalent to the electron spin resonance (ESR) spectrum and discuss three simple rules for qualitative prediction of the level-crossing spectra.

scholarly journals Ultrasmall magnetic field-effect and sign reversal in transistors based on donor/acceptor systems

2017 ◽  
Vol 8 ◽  
pp. 1104-1114 ◽  
Author(s):  
Thomas Reichert ◽  
Tobat P I Saragi
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Magnetic Field Effect ◽  
Charge Carrier Density ◽  
Magnetic Field Effects ◽  
Organic Field Effect Transistors ◽  
Transport Channel ◽  
Sign Reversal ◽  
Donor Acceptor

We present magnetoresistive organic field-effect transistors featuring ultrasmall magnetic field-effects as well as a sign reversal. The employed material systems are coevaporated thin films with different compositions consisting of the electron donor 2,2',7,7'-tetrakis-(N,N-di-p-methylphenylamino)-9,9'-spirobifluorene (Spiro-TTB) and the electron acceptor 1,4,5,8,9,12-hexaazatriphenylene hexacarbonitrile (HAT-CN). Intermolecular charge transfer between Spiro-TTB and HAT-CN results in a high intrinsic charge carrier density in the coevaporated films. This enhances the probability of bipolaron formation, which is the process responsible for magnetoresistance effects in our system. Thereby even ultrasmall magnetic fields as low as 0.7 mT can influence the resistance of the charge transport channel. Moreover, the magnetoresistance is drastically influenced by the drain voltage, resulting in a sign reversal. An average B 0 value of ≈2.1 mT is obtained for all mixing compositions, indicating that only one specific quasiparticle is responsible for the magnetoresistance effects. All magnetoresistance effects can be thoroughly clarified within the framework of the bipolaron model.

scholarly journals Development of Lock-in Based Overtone Modulated MARY Spectroscopy for Detection of Weak Magnetic Field Effects

2020 ◽  
Author(s):  
Marcin Konowalczyk ◽  
Olivia Foster Vander Elst ◽  
Jonathan Storey
Keyword(s):  
Magnetic Field ◽  
Weak Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Reaction Yield ◽  
Magnetic Field Effects ◽  
Detection Scheme ◽  
Natural Isotopic Abundance ◽  
Field Effects ◽  
High Modulation

Modulated magnetically altered reaction yield (ModMARY) spectroscopy is a derivative variant of fluorescence detected magnetic field effect measurement, where the applied magnetic field has both a constant and a modulated component. As in many derivative spectroscopy techniques, the signal to noise ratio scales with the magnitude of the modulation. High modulation amplitudes, however, distort the signal and can obscure small features of the measured spectrum. In order to detect weak magnetic field effects (including the low field effect) a balance of the two has to be found. In this work we look in depth at the origin of the distortion of the MARY signal by field modulation. We then present an overtone detection scheme, as well as a data analysis method which allows for correct fitting of both harmonic and overtone signals of the modulation broadened MARY data. This allows us to robustly reconstruct the underlying MARY curve at different modulation depths. To illustrate the usefulness of the technique, we show measurements and analysis of a well known magnetosensitive system of pyrene / 1,3-dicyanobenzene (Py/DCB). The measurements of first (h1) and second (h2) harmonic spectra are performed at different modulation depths for both natural isotopic abundance, and perdeuterated pyrene samples.<br>

Magnetic field effects of photocarrier generation in bulk heterojunctions at low temperature

2016 ◽  
Vol 45 (42) ◽  
pp. 16616-16623 ◽  
Author(s):  
H. Tajima ◽  
Y. Nishioka ◽  
S. Sato ◽  
T. Suzuki ◽  
M. Kimata
Keyword(s):  
Magnetic Field ◽  
Experimental Investigation ◽  
Low Temperature ◽  
Field Effect ◽  
Bulk Heterojunction ◽  
Magnetic Field Effect ◽  
Magnetic Field Effects ◽  
Bulk Heterojunctions ◽  
Polymer Bulk ◽  
The Magnetic Field

We report an experimental investigation of the magnetic field effect (MFE) in polymer bulk heterojunction devices at temperatures below 10 K using photocarrier extraction by linearly increasing voltages.

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