Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes
Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes
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DOI：
10.1063/1.5084216
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发表时间：
2019-03
影响因子：
3.2
通讯作者：
K. Kanemoto;Shuto Hatanaka;Takayuki Suzuki
中科院分区：
文献类型：
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作者：
K. Kanemoto;Shuto Hatanaka;Takayuki Suzuki
利用电探测和电探测磁共振（EDMR和ELDMR）技术研究了有机发光二极管（oled）中电流磁场效应（MFEs）和电致发光（EL）强度的偏置依赖行为。仅电子器件没有检测到EDMR信号，并且仅空穴器件只给出比OLED器件小得多的EDMR信号。从OLED中观察到的EDMR和ELDMR信号主要是由电子-空穴（e-h）对的自旋依赖反应引起的。增加OLED的工作偏置会降低归一化EDMR和ELDMR的信号强度，因为偏置的增加会增强e-h对的解离和重组，而不是偏置对对密度的增加。磁导率和磁电强度的偏置曲线分别与归一化EDMR和ELDMR的偏置曲线非常相似。这种相似性直接证明了e-h对决定了当前oled在室温下的MFEs，而MFEs是由e-h对的偏倚解离和重组而降低的。因此，偏置相关的EDMR和ELDMR实验是有效的探测方法，可以通过e-h对检测oled的磁场特性。利用电探测和电探测磁共振（EDMR和ELDMR）技术研究了有机发光二极管（oled）中电流磁场效应（MFEs）和电致发光（EL）强度的偏置依赖行为。仅电子器件没有检测到EDMR信号，并且仅空穴器件只给出比OLED器件小得多的EDMR信号。从OLED中观察到的EDMR和ELDMR信号主要是由电子-空穴（e-h）对的自旋依赖反应引起的。增加OLED的工作偏置会降低归一化EDMR和ELDMR的信号强度，因为偏置的增加会增强e-h对的解离和重组，而不是偏置对对密度的增加。磁导率和磁电强度的偏置曲线分别与归一化EDMR和ELDMR的偏置曲线非常相似。这种相似性直接证明了……
The bias dependent behaviors in magnetic field effects (MFEs) of the current and the electroluminescence (EL) intensity in organic light emitting diodes (OLEDs) have been investigated from electrically-detected and EL-detected magnetic resonance (EDMR and ELDMR) techniques. An EDMR signal was not detected from the electron-only device, and the hole-only device gave only a much smaller EDMR signal than the OLED device. Both the EDMR and ELDMR signals observed from the OLED are concluded to primarily arise from the spin-dependent reaction of electron-hole (e-h) pairs. Both the normalized EDMR and ELDMR signal intensities decrease by increasing the operation bias of OLED, because the increased bias enhances the dissociation and recombination of e-h pairs beyond the increase in the pair-density by the bias. The bias-dependence curves of magneto-conductances and magneto-EL intensities are demonstrated to be very similar to those of the normalized EDMR and ELDMR, respectively. This similarity gives direct evidence that e-h pairs determine the MFEs of the present OLEDs at room temperature and that the MFEs are reduced by bias-dependent dissociation and recombination of e-h pairs. The bias-dependent EDMR and ELDMR experiments are thus effective as probing methods to examine the magnetic field properties via e-h pairs of OLEDs.The bias dependent behaviors in magnetic field effects (MFEs) of the current and the electroluminescence (EL) intensity in organic light emitting diodes (OLEDs) have been investigated from electrically-detected and EL-detected magnetic resonance (EDMR and ELDMR) techniques. An EDMR signal was not detected from the electron-only device, and the hole-only device gave only a much smaller EDMR signal than the OLED device. Both the EDMR and ELDMR signals observed from the OLED are concluded to primarily arise from the spin-dependent reaction of electron-hole (e-h) pairs. Both the normalized EDMR and ELDMR signal intensities decrease by increasing the operation bias of OLED, because the increased bias enhances the dissociation and recombination of e-h pairs beyond the increase in the pair-density by the bias. The bias-dependence curves of magneto-conductances and magneto-EL intensities are demonstrated to be very similar to those of the normalized EDMR and ELDMR, respectively. This similarity gives direct evide...