Stability of polymer light-emitting diodes

Berntsen, A. J. M.; Weijer, Peter van de; Croonen, Y.; Liedenbaum, C.T.H.F.; Vleggaar, J.J.M.

doi:10.1016/s0165-5817(98)00021-7

Cited by 39 publications

(13 citation statements)

References 8 publications

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“…Upon entering the diode, they cause the following failures: 1) Delamination of the interfaces between various layers, particularly the interface between cathode and organic EL layer. [10,11,22] 2) Corrosion of active metals used as part of cath- Fig. 9.…”

Section: Process and Mechanism Of Dark Spotsmentioning

confidence: 99%

Understanding Dark Spot Formation and Growth in Organic Light-Emitting Devices by Controlling Pinhole Size and Shape

Lim

Wang²,

Chua

2002

Adv. Funct. Mater.

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We report on our in‐situ experimental observations of dark spots in organic light‐emitting diodes using optical microscopy. Uniformly sized silica microparticles are used to intentionally create size‐ and shape‐controllable pinholes on the cathode protective layer. Subsequently, the pinholes trigger the initial formation of dark spots, which we then monitor. Due to the use of particles of various diameters, we are able to linearly associate the growth rate with pinhole size. This allows us to estimate the original pinhole sizes that give rise to the dark spots and to study their distribution. Our studies verify that pinholes on the protective layer create pathways for water or oxygen diffusion, which controls the dark spot growth rate. The pinhole size dependence illustrates that the pinhole perimeter (not the area) determines the amount of water or oxygen diffusing into the diodes at a certain time.

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Section: Process and Mechanism Of Dark Spotsmentioning

confidence: 99%

Understanding Dark Spot Formation and Growth in Organic Light-Emitting Devices by Controlling Pinhole Size and Shape

Lim

Wang²,

Chua

2002

Adv. Funct. Mater.

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“…[1][2][3][4][5][6] The improvements have been directed towards advanced synthesis of suitable polymers and understanding of the electrical properties, like charge injection, charge transport, and electron-hole balance. [7][8][9][10][11][12][13][14][15][16][17] These parameters are of course of vital importance for the device performance.…”

Section: Introductionmentioning

confidence: 99%

Luminescence probing of crystallization in a polymer film

Granlund

Pettersson

Andersson

et al. 2000

Journal of Applied Physics

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Articles you may be interested inNear-infrared photoconductive and photovoltaic devices using single-wall carbon nanotubes in conductive polymer films J. Appl. Phys. 98, 084314 (2005); 10.1063/1.2113419 Modeling disorder in polymer aggregates: The optical spectroscopy of regioregular poly(3-hexylthiophene) thin films J. Chem. Phys. 122, 234701 (2005); 10.1063/1.1914768 Polarized luminescence and absorption of highly oriented, fully conjugated, heterocyclic aromatic rigid-rod polymer poly-p-phenylenebenzobisoxazole J. Appl. Phys. 95, 417 (2004); 10.1063/1.1632021 Ionomeric control of interchain interactions, morphology, and the electronic properties of conjugated polymer solutions and filmsWe report studies of a thin film multilayer stack including a highly emissive substituted polythiophene, poly͓3-͑2,5-dioctylphenyl͒thiophene͔. Analysis of the photoluminescence spectra revealed an inhomogeneous polymer film. X-ray diffraction studies attribute the existence of an inhomogeneous film as originating from crystallization of the polymer. We used the interference effect of light to detect the region of crystallization in the film. Photoluminescence and absorption were redshifted upon crystallization and displayed an enhanced vibronic structure. Comparison between calculated and measured photoluminescence shows that the crystallization starts from the top of the film and not from the supporting substrate.

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“…P3HT:PCBM), and (iv) a low work function cathode. The spin-coated PEDOT:PSS layer improves the alignment of the energy levels of the anode and the highest occupied molecular orbital (HOMO) of the donor-material, and planarizes spikes created during ITO sputtering, that would otherwise penetrate the thin photoactive layer and decrease device efficiency [4][5][6]. In some cases the ITO anode can even be fully replaced by high conductive (HC) grades of PEDOT:PSS [7,8].…”

Section: Introductionmentioning

confidence: 99%