Flexible white organic light-emitting diodes with a multi-metal electrode and a new combination of heteroleptic iridium compound

One of the core technologies of transparent organic light-emitting diodes (TOLEDs) is to develop an optically transparent and high electrical conductivity electrode so that light generated inside the device can efficiently escape into the air through the electrodes. We recently reported in TOLED research that two flipping processes are required to dry-transfer the front multilayered graphene (MLG) to the top electrode, while the rear MLG requires one dry transfer process. As the transfer process increases, the electrical properties of graphene deteriorate due to physical damage and contamination by impurities. At the charge-injecting layer/MLG interface constituting the TOLED, the rear MLG electrode has significantly lower charge injection characteristics than the front MLG electrode, so it is very important to improve the electrical characteristics of the rear MLG. In this paper, we report that the light-emitting properties of the TOLED are improved when an oxygen plasma-treated rear MLG is used as the top electrode, as compared with untreated rear MLG. In addition, the fabricated device exhibits a transmittance of 74–75% at the maximum electroluminescence wavelength, and the uniformity of transmittance and reflectance is more constant at a wavelength of 400–700 nm than in a device with a metal electrode. Finally, near-edge X-ray absorption fine structure spectroscopic analysis proves that the MLG crystallinity is improved with the removal of impurities on the surface after oxygen plasma treatment.

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Systematic investigation of transparent organic light-emitting diodes depending on top metal electrode thickness

Organic Electronics ◽

10.1016/j.orgel.2011.05.006 ◽

2011 ◽

Vol 12 (8) ◽

pp. 1383-1388 ◽

Cited By ~ 24

Author(s):

Jonghee Lee ◽

Simone Hofmann ◽

Mauro Furno ◽

Michael Thomschke ◽

Yong Hyun Kim ◽

...

Keyword(s):

Light Emitting Diodes ◽

Metal Electrode ◽

Systematic Investigation ◽

Organic Light Emitting Diodes ◽

Electrode Thickness ◽

Light Emitting ◽

Organic Light

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White organic light-emitting diodes with 4 nm metal electrode

Applied Physics Letters ◽

10.1063/1.4934274 ◽

2015 ◽

Vol 107 (16) ◽

pp. 163302 ◽

Cited By ~ 17

Author(s):

Simone Lenk ◽

Tobias Schwab ◽

Sylvio Schubert ◽

Lars Müller-Meskamp ◽

Karl Leo ◽

...

Keyword(s):

Light Emitting Diodes ◽

Metal Electrode ◽

Organic Light Emitting Diodes ◽

Light Emitting ◽

Organic Light

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Improving organic/electrode interface in organic light-emitting diodes by soft contact Iamination

Proceedings of the Institution of Mechanical Engineers Part N Journal of Nanoengineering and Nanosystems ◽

10.1243/174034905x68850 ◽

2005 ◽

Vol 219 (1) ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

T-W Lee ◽

J. W. P. Hsu

Keyword(s):

Light Emitting Diodes ◽

Metal Electrode ◽

Organic Light Emitting Diodes ◽

Organic Layer ◽

Metal Electrodes ◽

Soft Contact ◽

Light Emitting ◽

Organic Light ◽

Organic Electrode ◽

Metal Organic

Organic light-emitting diodes (OLEDs), with few exvceptions, are fabricated in the standard way of sequentially depositing active layers and elecrodes onto a substrate. The conventional devices have ‘a detrimental layer’ at the interface between the organic and the top metal electrode because evaporation results in metal in-diffusion and chemical disruption at the metal-organic interface, Here, a different approach is introduced to construct OLEDs: soft contact lamination (SCL) is based on thysical lamination of thin metal electrodes supported by an elastomeric layer against the electrolumnescent organic layer. Thei method produces spatially homogeneous, intimate contacts via van der Waals interaction between the metal and the organic, resulting in no chemical and physical damages to the organic. Devices fabricated by SCL are shown to have no detrimental layer and fewer luminescence-quenching channels than conventional devices that have evaporated top metal electrodes.

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