Singlet-to-triplet interconversion using hyperfine as well as ferromagnetic fringe fields

Wohlgenannt, M.; Flatté, Michael E.; Harmon, Nicholas J.; Wang, F.; Kent, Andrew D.; Maciá, Ferran

doi:10.1098/rsta.2014.0326

Cited by 2 publications

(2 citation statements)

References 32 publications

(51 reference statements)

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“…Most species formed in the course of charge generation and charge separation in organic solar cells are inherently paramagnetic. Nevertheless, the role of the electron spin on kinetics of recombination and therefore eventually the efficiency of OPV devices has only recently been highlighted (Rao et al, 2013; Wohlgenannt et al, 2015). In the dark, however, ideally there should be no paramagnetic species present.…”

Section: Paramagnetic States In Organic Photovoltaic Devicesmentioning

confidence: 99%

Structure–Function Relationship of Organic Semiconductors: Detailed Insights From Time-Resolved EPR Spectroscopy

Biskup

2019

Front. Chem.

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Organic photovoltaics (OPV) is a promising technology to account for the increasing demand for energy in form of electricity. Whereas the last decades have seen tremendous progress in the field witnessed by the steady increase in efficiency of OPV devices, we still lack proper understanding of fundamental aspects of light-energy conversion, demanding for systematic investigation on a fundamental level. A detailed understanding of the electronic structure of semiconducting polymers and their building blocks is essential to develop efficient materials for organic electronics. Illuminating conjugated polymers not only leads to excited states, but sheds light on some of the most important aspects of device efficiency in organic electronics as well. The interplay between electronic structure, morphology, flexibility, and local ordering, while at the heart of structure—function relationship of organic electronic materials, is still barely understood. (Time-resolved) electron paramagnetic resonance (EPR) spectroscopy is particularly suited to address these questions, allowing one to directly detect paramagnetic states and to reveal their spin-multiplicity, besides its clearly superior spectral resolution compared to optical methods. This article aims at giving a non-specialist audience an overview of what EPR spectroscopy and particularly its time-resolved variant (TREPR) can contribute to unraveling aspects of structure–function relationship in organic semiconductors.

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Section: Paramagnetic States In Organic Photovoltaic Devicesmentioning

confidence: 99%

Structure–Function Relationship of Organic Semiconductors: Detailed Insights From Time-Resolved EPR Spectroscopy

Biskup

2019

Front. Chem.

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“…In this report, we study the ability of a thermally activated delayed fluorescence (TADF)-based OLED device in combination with an organic photodetector (OPD) to act as a magnetometer and alternative device geometry to MR-based sensors. While the TADF OLED exhibits some MR effect that is a fraction of the MEL, other common OLED materials might only exhibit a measurable MEL effect and no or weak MR, such as Alq 3 , MEHPPV, ADTs, and Rubrene. ,, For such cases, the herein-reported device structure enables the use of these materials. Furthermore, we show that a monolithic OLED/OPD stack can achieve sensitivities on the order of commercial Hall-sensors and promise detectivities beyond that of organic MR-based sensors.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Field Sensor Based on a OLED/Organic Photodetector Stack

Engmann,

Bittle,

Gundlach

2023

ACS Appl. Electron. Mater.

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In this study, an all-organic magnetic field sensor based on an organic light-emitting diode (OLED) and organic photodetector (OPD) layer stack is presented. This sensor opens possibilities to create printable, flexible magnetic field sensors using commercially viable components, allowing magnetic field sensors to be simply integrated into the existing OLED technology. The sensor function is driven by the large magneto-electroluminescence (MEL) of a thermally activated delayed fluorescence (TADF)emitter-based OLED, which in reference devices have shown an MEL of about 60% for magnetic fields on the order of 10 mT. Maximum sensitivity of about 0.15 nA/mT (150 μV/mT or 15 mV/kG with amplification) is achieved at a magnetic field of 3−4 mT. While the detectivity is limited to ∼10 −3 T•Hz −1/2 , we show this can be improved upon as the magnetic field detection sensitivity of OLEDs measured by an external Si-detector is about an order of magnitude higher. Sensitivity of 2 nA/mT and detectivities better than 10 −5 T•Hz −1/2 are demonstrated, and the intrinsic detectivity limit is estimated to be on the order of 10 −9 T•Hz −1/2 .

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Singlet-to-triplet interconversion using hyperfine as well as ferromagnetic fringe fields

Abstract: One contribution of 11 to a discussion meeting issue 'Organic semiconductor spintronics: utilizing triplet excitons in organic electronics' .

Cited by 2 publications

References 32 publications

Structure–Function Relationship of Organic Semiconductors: Detailed Insights From Time-Resolved EPR Spectroscopy

Structure–Function Relationship of Organic Semiconductors: Detailed Insights From Time-Resolved EPR Spectroscopy

Magnetic Field Sensor Based on a OLED/Organic Photodetector Stack

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