Extraordinary magnetic field effects mediated by spin-pair interaction and electron mobility in thermally activated delayed fluorescence-based OLEDs with quantum-well structure

Pan, Ruiheng; Tang, Xiantong; Hu, Yeqian; Zhu, Hong Qiang; Deng, Jinqiu; Xiong, Zuhong

doi:10.1039/c8tc06033a

Cited by 20 publications

(15 citation statements)

References 49 publications

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“…Figure 1b shows typical MEL profiles of 4CzIPN-based OLED under constant-current condition (MEL J ). To assess the origin of the MEL profiles, we performed a fitting analysis based on the Lorentzian and non-Lorentzian equations [16][17][18][19] Magnetic field effect ¼ ðLow À field effectÞ þ ðhigh À field effectÞ…”

Section: Resultsmentioning

confidence: 99%

“…The MEL profiles had two parts, indicating that there are two different mechanisms. Because B L is a comparable value for the PP mechanism, i.e., 5 mT [16][17][18][19] , the low-field effect originates from the PP mechanism that increases "bright" singlet excitons. The magnetic field suppresses the intersystem crossing between 1 PP and 3 PP states.…”

Section: Resultsmentioning

confidence: 99%

“…2b, d). Because of the proportionality between electroluminescence intensity and current density, the magneto-efficiency under constant voltage (Mη V ) was calculated by 16 Mη…”

Section: Resultsmentioning

confidence: 99%

“…Numerous studies regarding the mechanism of magnetic field effects on OLEDs based on fluorescent 11,12 , phosphorescent 13 , exciplex 14 , and TADF emitters 15,16 were investigated to unveil the underlying dynamics of exciton generation, radiation, and annihilation processes. PP 11,17 , triplet-polaron interactions (TPI) 16,18 , and TTA mechanisms 12,16 were mainly used to explain magnetic field effects. However, the interpretation of these effects has been unclear, and the relationship between exciton dynamics and OLED degradation has been lacking.…”

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confidence: 99%

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Understanding degradation of organic light-emitting diodes from magnetic field effects

et al. 2020

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The impact of magnetic field effects on the electroluminescence of organic light-emitting diodes is commonly used to characterize exciton dynamics such as generation, annihilation, and performance degradation. However, interpreting these effects is challenging. Here, we show that magnetic field effects in organic light-emitting diodes can be understood in terms of the magnetic response of device characteristics derived from polaron-pair and triplet exciton quenching processes, such as triplet-polaron interactions and triplet-triplet annihilation. Device degradation shows a clear relationship with the amplitude of the magnetic field effects, enabling non-destructive measurement of the degradation. The results and proposed mechanism provide a better understanding of magnetic field effects on organic light-emitting diodes and device degradation phenomena.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…2b, d). Because of the proportionality between electroluminescence intensity and current density, the magneto-efficiency under constant voltage (Mη V ) was calculated by 16 Mη…”

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Understanding degradation of organic light-emitting diodes from magnetic field effects

et al. 2020

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“…态极化子对(triplet polaron pairs, PP 3 ) [32] . 同时, 部分PP 1 和PP 3 也会分别以d S 和d T 解离成自由的载流子 [33] . 能以退激辐射的方式发出荧光 [11] .…”

Section: 和72×10unclassified

Abnormal temperature dependence of triplet-triplet annihilation in excimer-based devices

Zhao¹,

Tang²,

Pan³

et al. 2019

Chin. Sci. Bull.

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Energy Gain and Loss Processes in OLEDs with Spacer‐Separated Electron–Hole Pairs Investigated by Magnetic Field Effects

Liu,

Chen,

et al. 2024

Advanced Optical Materials

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Interfacial or diluted exciplex organic light emitting diodes (OLEDs) with spacer‐separated electron–hole pairs have emerged as a promising approach for precise tuning the energy level of charge‐transfer (CT) excitons and the improvement in device performance. However, their microscopic energy gain and loss mechanisms are not well understood. In this study, magnetic field effects (MFEs) including magneto‐electroluminescence (MEL), magneto‐conductance (MC), and magneto‐efficiency (Mη) in two series of donor‐spacer‐acceptor type exciplex‐based OLEDs, which exhibited opposite distance‐dependent device performances, are studied to explore the microscopic dynamics of spacer‐separated electron–hole pairs. Intersystem crossing (ISC) between CT excitons and between polaron‐pairs, reverse intersystem crossing (RISC) between CT excitons, triplet–triplet annihilation (TTA), scattering and dissociation channels of triplet‐charge annihilation (TQA), and additional Dexter energy transfer (DET) processes are identified. The decreased external quantum efficiency (EQE) and MEL with increasing thickness of space layer in Configuration II devices are attributed to an activation of the potential DET process from the lowest triplet of spacer‐separated CT excitons to the lowest triplet of Bphen caused by their smaller energy gaps. The study offers in‐depth insights into the exciton utilization and energy loss, which may allow better design and optimization of space‐modulated OLEDs.

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Extraordinary magnetic field effects mediated by spin-pair interaction and electron mobility in thermally activated delayed fluorescence-based OLEDs with quantum-well structure

Abstract: We fabricated quantum-well organic light-emitting diodes (QW-OLEDs) based on thermally activated delayed fluorescence (TADF) and measured their magnetic field effects curves over various magnetic field ranges.

Cited by 20 publications

References 49 publications

Understanding degradation of organic light-emitting diodes from magnetic field effects

Understanding degradation of organic light-emitting diodes from magnetic field effects

Abnormal temperature dependence of triplet-triplet annihilation in excimer-based devices

Energy Gain and Loss Processes in OLEDs with Spacer‐Separated Electron–Hole Pairs Investigated by Magnetic Field Effects

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