Impedance spectroscopy as a probe for the degradation of organic light-emitting diodes

Nowy, Stefan; Ren, Wenjie; Elschner, Andreas; Lövenich, Wilfried; Brütting, Wolfgang

doi:10.1063/1.3294642

Cited by 148 publications

(118 citation statements)

References 29 publications

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“…This means that all the organic compounds under investigation reduce more slowly than they oxidise. This result corresponds to a known fact that hole mobility in organic solid films is in most cases much higher than electron mobility [25,26]. Finally, the compounds used as host materials were found to be oxidised and reduced very slowly and irreversibly.…”

Section: Figure 12mentioning

confidence: 67%

Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy

Chulkin

Łapkowski

Santos

et al. 2017

Electrochimica Acta

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(2017) 'Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy.', Electrochimica Acta., 258 . pp. 1160-1172. Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Two main features concerning the redox reaction rates of OLED-active compounds were revealed: (i) the oxidation and reduction rates of ambipolar compounds, i.e. containing both donor and acceptor parts, were found to be much higher than those of unipolar donor-only and acceptoronly molecules; (ii) the relationship between the oxidation and reduction rate constants was shown to be related to the compounds' conductivity type in the solid state.

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Section: Figure 12mentioning

confidence: 67%

Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy

Chulkin

Łapkowski

Santos

et al. 2017

Electrochimica Acta

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“…For example, in [3] the usage of impedance spectroscopy is described; in [4] an approach using the forward voltage of the OLED is shown. These methods are all anticipated for analog driving and compensating the degradation of current efficiency.…”

Section: Acquisition Of Agingmentioning

confidence: 99%

19.2: Distinguished Student Paper: Compensation of OLED I‐V‐Drift for Suppressing Image Sticking in A Digital AMOLED Display Module

Volkert

2015

Symp Digest of Tech Papers

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“…Nevertheless, degradation mechanisms occur and display through a modification of the emission color and/or a reduction of the driving current and the luminance. The effect of aging leads to a progressive increase in impedance during the operation of OLEDs and in order to maintain a constant current, the bias polarization has to be raised more and more [13]. However, it was observed that half lifetime (the time for which the decrease in luminance is 50% from the initial value) and the initial decay are closely related to the amount of non-emissive triplets in emissive layer [9,10].…”

Section: Introductionmentioning

confidence: 97%

Application of [Pt(II)(Tetra-Tert-Butylsalophen)] Complex within Organic Devices: Deep Red Emission, Bistable Light-Emitting Diodes and Operational Stability

et al. 2018

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This paper focuses on the Negative Differential Resistance (NDR) we observed on organic light-emitting diodes (OLEDs) using [Pt(II)(tetra-tert-butylSalophen)] as host, since this Pt(II) complex displays a deep-red emission (λ max = 660 nm). Electrical characterizations of monolayer devices have shown that doping Tris-(8-hydroxyquinoline)aluminum (Alq 3 ) as matrix emissive layer with this complex, leads to the modulation of the charge transport properties highlighted by Negative Differential Resistance (NDR). Upon electrical driving stresses, the conductivity of active layer can be switched between two electrical states (ON and OFF) with a figure of merit higher than 10 3 . By adding an electron-blocking layer, we demonstrated that the NDR trend is closely related to negative charge accumulation within Alq 3 leading to the modification of electronic properties in the vicinity of anode/active layer interface. The NDR phenomenon is interpreted in terms of space charge polarization (SCP) linked to charge trapping/untrapping mechanism as a consequence of the polarization/depolarization of the Pt(II) complex. Under electrical driving stresses, the performance of the devices which include the Pt(II) complex, are stabilized. A schematic model is proposed to depict the SCP responsible for NDR and decrease-resetting behaviors observed in these devices.

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Impedance spectroscopy as a probe for the degradation of organic light-emitting diodes

Abstract: Nonradiative recombination centers and electrical aging of organic light-emitting diodes: Direct connection between accumulation of trapped charge and luminance loss

Cited by 148 publications

References 29 publications

Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy

Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy

19.2: Distinguished Student Paper: Compensation of OLED I‐V‐Drift for Suppressing Image Sticking in A Digital AMOLED Display Module

Application of [Pt(II)(Tetra-Tert-Butylsalophen)] Complex within Organic Devices: Deep Red Emission, Bistable Light-Emitting Diodes and Operational Stability

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