- Anodic oxidation of novel hole-transporting materials derived from tetraarylbenzidines. Electrochemical and spectroscopic characterization
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Fluorenylidene-linked triarylamines, potential hole-transporting materials, have been prepared by the palladium-catalyzed Hartwig-Buchwald animation. Their redox and spectral properties were investigated in solution, applying cyclic voltammetry, UV-VIS and WR spectroscopy, and in situ spectroelectrochemical measurements. N,N,N′,N′-Tetraphenylbenzidine (1), N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (2), and triphenylamine (3) served as model substances in the study of the synthesized complex compounds 4 and S. In structure 4, two triphenylamine centres are linked with a non-conjugated fluorene bridge; in structure 5, two tetraarylbenzidine skeletons with two nitrogens are linked with a conjugated biphenyl-bridge system. In addition, structure 5 contains a non-conjugated fluorene bridge. The presence of the fluorene moiety in the molecular design has a significant influence on the investigated properties of the new materials. In the anodic oxidation of the tetraarylbenzidine-type compounds (1, 2, and 5), two well-defined reversible oxidation peaks were observed. However, the oxidation of the triphenylamine-type structures (3 and 4) is more complex, due to fast consecutive reactions. The dimer-like structures (4 and 5) are characterized by two independent oxidation centres that are simultaneously oxidized at approximately the same potentials. This was confirmed by quantitative cyclovoltammetric as well as UV-VIS investigations.
- Faber, Rene,Mielke, G. Felix,Rapta, Peter,Stasko, Andrej,Nuyken, Oskar
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- Fluorine cleavage of the light blue heteroleptic triplet emitter FIrpic
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The lifetime stability of devices containing FIrpic as emitter has been a major concern for organic blue light emitting devices (OLEDs). To gain a deeper knowledge about the purity of FIrpic (bis[2-(4,6-difluorophenyl)pyridyl-N,C2′]iridium (III)) emitters
- Sivasubramaniam, Varatharajan,Brodkorb, Florian,Hanning, Stephanie,Loebl, Hans Peter,van Elsbergen, Volker,Boerner, Herbert,Scherf, Ullrich,Kreyenschmidt, Martin
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- COMPOUNDS AND ORGANIC LIGHT EMITTING DIODE USING THE SAME
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Disclosed are new compounds and an organic light emitting diode using the same. The organic light emitting diode using the new compound according to the present invention exhibits excellent characteristics in terms of actuating voltage, light efficiency, and lifespan.
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Page/Page column 117-118
(2010/04/23)
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- AROMATIC AMINE DERIVATIVES AND ELECTROLUMINESCENCE DEVICE USING THE SAME
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An aromatic amine derivative with a specific structure and an organic electroluminescence device which comprises at least one organic thin film layer comprising a light emitting layer sandwiched between a pair of electrode consisting of an anode and a cat
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- Synthesis and characterization of photo-cross-linkable hole-conducting polymers
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The synthesis and characterization of side-chain polymers functionalized with hole-transporting units and photo-cross-linkable groups, which can be used for solution-based preparation of multilayer organic light-emitting devices (OLEDs), are discussed. The concept deals with triarylamine and oxetane-functionalized styrenes, which are copolymerized by radical polymerization. Four different types of hole-transporting monomers were combined with one cross-linkable monomer in two different ratios, yielding two groups of each four polymers (P1A...P4A and P1B...P4B). The polymers were investigated by NMR spectroscopy, molecular weights were determined by GPC with light scattering, and the thermal properties were measured with differential scanning calorimetry (DSC). Optical characterization by UV-vis and fluorescence spectroscopy was performed. Electrochemical and cross-linking characteristics of the copolymers were investigated to proove this strategy's potential in application for modern multilayer polymer OLEDs. Finally, hole-only devices were prepared for evaluation of the semiconductive performance of the materials.
- Bacher, Erwin,Bayerl, Michael,Rudati, Paula,Reckefuss, Nina,Mueller, C.David,Meerholz, Klaus,Nuyken, Oskar
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p. 1640 - 1647
(2007/10/03)
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