Organic Light‐emitting Diodes Based on Solution‐Processable Organic Materials

Andreopoulou, Aikaterini K.; Gioti, M.; Kallitsis, Joannis K.

doi:10.1002/9783527813872.ch8

Cited by 7 publications

(7 citation statements)

References 242 publications

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“…At a voltage higher than 2.7 V, denoted below as a space charge formation voltage, U scf , the system becomes symmetrical (Figure 5c). The K coefficient value close to 1 2 and at almost equal time constants (Figure 4) confirms that conclusion.…”

Section: The Fully Protected Pledssupporting

confidence: 84%

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Three Destinies of Solution-Processable Polymer Light-Emitting Diodes under Long-Time Operation

et al. 2021

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The article describes three different ways of polymer light-emitting diode (PLED) degradation, caused by damage of the protective layer. The electroluminescence and charge-transport properties of a completely encapsulated diode, the diodes with a leaky protective layer and diodes without encapsulation were compared under long-time exploitation. The studied devices incorporated Super Yellow light-emitting poly-(1,4-phenylenevinylene) PPV copolymer as an electroluminescence component, and (poly-(3,4-ethylenedioxythiophene)–poly-(styrene sulfonate) (PEDOT:PSS) as a charge-transport layer between the indium tin oxide (ITO) anode and aluminum–calcium cathode. To analyze the PLED degradation mechanism regarding charge transport, impedance spectroscopy was used. The values of resistance and capacitance of the internal layers revealed an effect of applied voltage on charge carrier injection and recombination. The factors responsible for the device degradation were analyzed on a macromolecular level by comparing the plots of voltage dependence of resistance and capacitance at different operation times elapsed.

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Section: The Fully Protected Pledssupporting

confidence: 84%

“…Compared to their inorganic counterparts, PLEDs with thin organic layers are lighter, more flexible and use less energy. However, the wide application of PLEDs is limited so far by several problems, such as lifetime and vulnerability to mechanical damage and chemical corrosion caused by water and oxygen penetration [ 1 , 2 ].…”

Section: Introductionmentioning

confidence: 99%

Three Destinies of Solution-Processable Polymer Light-Emitting Diodes under Long-Time Operation

et al. 2021

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“…In recent years, tremendous advances in the field of Polymer Light-Emitting Diodes (PLEDs) have been achieved mainly through the synthesis of novel emitting materials and the development of improved device architectures [1][2][3][4][5]. In particular, scientific interest has largely increased in White Organic Light-Emitting Diodes (WOLEDs) processed from wetbased techniques, which have strong potential for use in future solid-state light sources and flat panel displays [1][2][3][4][5][6][7][8][9]. The wet-based fabrication process of such devices is compatible with automated roll-to-roll coating, which can allow upscaling to large scale industrial production of these devices [1,4,7].…”

Section: Introductionmentioning

confidence: 99%

“…In particular, scientific interest has largely increased in White Organic Light-Emitting Diodes (WOLEDs) processed from wetbased techniques, which have strong potential for use in future solid-state light sources and flat panel displays [1][2][3][4][5][6][7][8][9]. The wet-based fabrication process of such devices is compatible with automated roll-to-roll coating, which can allow upscaling to large scale industrial production of these devices [1,4,7].…”

Section: Introductionmentioning

confidence: 99%

Photophysical and Electro-Optical Properties of Copolymers Bearing Blue and Red Chromophores for Single-Layer White OLEDs

et al. 2021

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In this study, novel copolymers consisting of blue and red chromophores are presented to induce emission tuning, enabling the definition of white light emission in a single polymeric layer. These aromatic polyether sulfones exhibit high molecular weights, excellent solubility and processability via solution deposition techniques. In addition, by carefully controlling the molar ratios of chromophores composition, the energy transfer mechanism, from blue to red chromophores, takes place enabling us to define properly the emission covering the entire range of the visible spectrum. The optical and photophysical properties of the monomers and copolymers were thoroughly investigated via NIR-Vis-far UV Spectroscopic Ellipsometry (SE), Absorbance and Photoluminescence (PL). These copolymers are used as an emissive layer and applied in solution-processed WOLED devices. The fabricated WOLED devices have been subsequently studied and characterized in terms of their electroluminescence properties. Finally, the WOLED devices possess high color stability and demonstrate CIE Coordinates (0.33, 0.38), which approach closely the pure white light CIE coordinates.

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“…As explained above, solution-processable small molecular Ir(III) complexes have been widely employed as “guest” molecules in combination with “host” polymers according to their energy levels and color emissions. On the contrary, only a handful solution-processable Ir(III)-bearing polymers have been identified as potential candidates, whether as standalone or blend components, for the EMLs of OLEDs [ 33 ]. In general, polymer metallocomplexes are an attractive solution, as they uniquely combine the advantages of small-molecular complexes with polymers’ superior film-forming properties and excellent thermal and chemical stability.…”

Section: Introductionmentioning

confidence: 99%

Bis-Tridendate Ir(III) Polymer-Metallocomplexes: Hybrid, Main-Chain Polymer Phosphors for Orange–Red Light Emission

et al. 2020

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In this work, hybrid polymeric bis-tridentate iridium(III) complexes bearing derivatives of terpyridine (tpy) and 2,6-di(phenyl) pyridine as ligands were successfully synthesized and evaluated as red-light emitters. At first, the synthesis of small molecular bis-tridendate Ir(III) complexes bearing alkoxy-, methyl-, or hydroxy-functionalized terpyridines and a dihydroxyphenyl-pyridine moiety was accomplished. Molecular complexes bearing two polymerizable end-hydroxyl groups and methyl- or alkoxy-decorated terpyridines were copolymerized with difluorodiphenyl-sulphone under high temperature polyetherification conditions. Alternatively, the post-polymerization complexation of the terpyridine-iridium(III) monocomplexes onto the biphenyl-pyridine main chain homopolymer was explored. Both cases afforded solution-processable metallocomplex-polymers possessing the advantages of phosphorescent emitters in addition to high molecular weights and excellent film-forming ability via solution casting. The structural, optical, and electrochemical properties of the monomeric and polymeric heteroleptic iridium complexes were thoroughly investigated. The polymeric metallocomplexes were found to emit in the orange–red region (550–600 nm) with appropriate HOMO and LUMO levels to be used in conjunction with blue-emitting hosts. By varying the metal loading on the polymeric backbone, the emitter’s specific emission maxima could be successfully tuned.

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Organic Light‐emitting Diodes Based on Solution‐Processable Organic Materials

Cited by 7 publications

References 242 publications

Three Destinies of Solution-Processable Polymer Light-Emitting Diodes under Long-Time Operation

Three Destinies of Solution-Processable Polymer Light-Emitting Diodes under Long-Time Operation

Photophysical and Electro-Optical Properties of Copolymers Bearing Blue and Red Chromophores for Single-Layer White OLEDs

Bis-Tridendate Ir(III) Polymer-Metallocomplexes: Hybrid, Main-Chain Polymer Phosphors for Orange–Red Light Emission

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