Electrically Detected Magnetic Resonance Spectroscopy

Boehme, Christoph; Malissa, H.

doi:10.1002/9780470034590.emrstm1525

Cited by 10 publications

(7 citation statements)

References 102 publications

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“…Despite providing the ability to probe Overhauser distributions directly, electrically detected magnetic resonance (EDMR) is blind to the spatial information which would allow one to probe local variations to these distributions, while its optical counterpart (ODMR) is experimentally challenging to resolve due to the weak signal produced under the resonance condition. [ 28 ] We have provided a first measure of the spatial resolution of ODMR over several ≈60 µm × 60 µm regions across the device (Figure S25, Supporting Information). While our ability to resolve variations in the widths of these curves is currently limited (and will be addressed in future work), we were able to detect changes in the amplitude of ODMR arising from the spatial gradient of the B 1 field generated by the resonator.…”

Section: Impacts Of Overhauser Variation On Spin‐reliant Applicationsmentioning

confidence: 99%

Resolving the Spatial Variation and Correlation of Hyperfine Spin Properties in Organic Light‐Emitting Diodes

et al. 2022

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under the application of relatively weak magnetic fields point toward their application as quantum sensors at room temperature. [17,18] Their fabrication flexibility and industrial use in commercial displays [19] underlie recent advances toward the miniaturization and integration of quantum technologies based on these materials. [20][21][22] For effective integration or miniaturization, reproducibility is crucial, and this extends to those properties of materials which impact spin-dependent processes. In this work, we aim to measure the variation of a critical spin property common to organic materials, the Overhauser field, which arises from the hyperfine coupling of charge-carrier spins to the bath of randomly oriented nuclear spins in the molecular environment. [23] The Overhauser field underlies a range of phenomena observed in organic devices, including magnetoresistive and magnetic resonant effects in organic light-emitting diodes (OLEDs), [24][25][26][27][28] both of which have been proposed as a mechanism to enable magnetic field sensing. [17,26] To date, the Overhauser field has been treated as a bulk property of the device, characterized by a single value that describes its impact. [26,29] If this is not a good assumption, it will present a significant challenge as we move toward high spatial resolution of magnetic fields [30,31] in organic devices. [32,33] We will demonstrate in the following sections that the Overhauser field indeed shows substantial intra-device variation by spatially resolving the magnetoluminescence effect exhibited by both a copolymer Super Yellow poly(phenylene-vinylene) (SY-PPV) and a small-molecule tris-(8-hydroxyquinoline) aluminum (Alq 3 ) OLED. As the Overhauser field is central to a wide range of spin-enabled functionality in organic devices, this variation presents a fundamental challenge for efforts to miniaturize and integrate such devices. Concept Magneto-Electroluminescence in OLEDsWe employ a stable and widely investigated active material-SY-PPV-to characterize the spatial variation of the Overhauser field in a simple vertical structure OLED (Figure 1a) and extract Devices that exploit the quantum properties of materials are widespread, with quantum information processors and quantum sensors showing significant progress. Organic materials offer interesting opportunities for quantum technologies owing to their engineerable spin properties, with spintronic operation and spin resonance magnetic-field sensing demonstrated in research grade devices, as well as proven compatibility with large-scale fabrication techniques. Yet several important challenges remain as moving toward scaling these proof-of-principle quantum devices to larger integrated logic systems or spatially smaller sensing elements, particularly those associated with the variation of quantum properties both within and between devices. Here, spatially resolved magnetoluminescence is used to provide the first 2D map of a hyperfine spin property-the Overhauser field-in traditional organic light-emitting diodes (...

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Section: Impacts Of Overhauser Variation On Spin‐reliant Applicationsmentioning

confidence: 99%

Resolving the Spatial Variation and Correlation of Hyperfine Spin Properties in Organic Light‐Emitting Diodes

et al. 2022

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“…In the following, we show that the high mobilities of PETDOT:PSS at low temperature cause montional narrowing of charge carrier hyperfine fields and that the arXiv:1804.05139v1 [cond-mat.mes-hall] 14 Apr 2018 ability to tune mobilities using EG [20] also enables the tunability of effective charge carrier hyperfine fields and associated observables such as charge carrier spin coherence times. In order to detect motional narrowing, we measured the distribution of local effective hyperfine field strengths as well as the spin decoherence times (T 2 ) using continuous wave (cw) [22] and pulsed (p) [23] electrically detected magnetic resonance (EDMR) spectroscopies. In order to detect EDMR, changes of spin-dependent currents of paramagnetic charge carriers are measured while the charge carrier spin states are brought into resonance [22].…”

mentioning

confidence: 99%

Tuning effective hyperfine fields in PEDOT:PSS thin films by doping

et al. 2018

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Using electrically detected magnetic resonance spectroscopy, we demonstrate that doping the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) with ethylene glycol allows for the control of effective local charge carrier hyperfine fields through motional narrowing. These results suggest that doping of organic semiconductors could enable the tuning of macroscopic material properties dependent on hyperfine fields such as magnetoresistance, the magneto-optical responses and spin-diffusion.

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“…[31,32] Electrically detected magnetic resonance (EDMR) can be used to study the charge transport mechanisms and spin physics in conducting polymers. [27,33,34] Interestingly, it was recently shown that the spin diffusion constant can be much larger than the charge diffusion constant. [35] This opens up new perspectives regarding qubit readout by spin currents rather than charge currents.…”

Section: Introductionmentioning

confidence: 99%

“…[ 43 ] We demonstrate that the charge transport is only a little affected by the presence of the MQBs. The polaronic charge transport processes were shown to be spin‐dependent by EDMR experiments, [ 33 ] proving the principle viability of electrical readout out of the MQBs. We demonstrate that chemical doping, leading to the presence of mobile charge carriers in the material, has only limited effect on spin dynamics times.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Spintronic Materials from Conducting Polymers with Molecular Quantum Bits

Kern

Tesi

Neußer

et al. 2020

Adv Funct Materials

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Hybrid materials consisting of organic semiconductors and molecular quantum bits promise to provide a novel platform for quantum spintronic applications. However, investigations of such materials, elucidating both the electrical and quantum dynamical properties of the same material have never been reported. Here the preparation of hybrid materials consisting of conducting polymers and molecular quantum bits is reported. Organic field-effect transistor measurements demonstrate that the favorable electrical properties are preserved in the presence of the qubits. Chemical doping introduces charge carriers into the material, and variable-temperature charge transport measurements reveal the existence of mobile charge carriers at temperatures as low as 15 K. Importantly, quantum coherence of the qubit is shown to be preserved up to temperatures of at least 30 K, that is, in the presence of mobile charge carriers. These results pave the way for employing such hybrid materials in novel molecular quantum spintronic architectures.

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Electrically Detected Magnetic Resonance Spectroscopy

Cited by 10 publications

References 102 publications

Resolving the Spatial Variation and Correlation of Hyperfine Spin Properties in Organic Light‐Emitting Diodes

Resolving the Spatial Variation and Correlation of Hyperfine Spin Properties in Organic Light‐Emitting Diodes

Tuning effective hyperfine fields in PEDOT:PSS thin films by doping

Hybrid Spintronic Materials from Conducting Polymers with Molecular Quantum Bits

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