Electroluminescence from Well-Defined Tetrahedral Oligophenylenevinylene Tetramers

Robinson, Matthew R.; Wang, S.; Bazan, Guillermo C.; Cao, Yong

doi:10.1002/1521-4095(200011)12:22<1701::aid-adma1701>3.0.co;2-u

Cited by 94 publications

(52 citation statements)

References 9 publications

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“…The compounds 2,5-dioctyloxy-4-iodobenzaldehyde, 2,5-dioctyloxy-1-styryl-4-(49-vinylstyryl)benzene [6] (1), and tetra(4-iodophenyl)methane [19] were prepared according to literature precedents. NMR spectra were obtained using a Varian Unity 400 spectrometer.…”

Section: Methodsmentioning

confidence: 99%

“…The olefin 2 was built with Wittig and Heck reactions in two steps from the distyrylbenzene derivative 1, which was synthesized by adapting literature procedures. [6] Chromatography on silica using a mixture of hexane and dichloromethane removes unreacted 2 from T-6R-OC 8 H 17 . The product obtained in this manner is a mixture of cis±trans isomers.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…The use of various cathodes and anode buffers, which better match the electronic levels of T-6R-OC 8 H 17 , should result in emission near the highest occupied molecular orbital±lowest unoccupied molecular orbital (HOMO±LUMO) energy difference, as seen in previous devices using 4-ring tetrahedral oligo-PVs . [6] The simplest device architecture corresponds to ITO/T-6R-OC 8 H 17 /Ba/Al. Light is detected between 5.5 V and 8 V, depending on the casting solvent and thickness.…”

Section: Electroluminescencementioning

confidence: 99%

“…[2±4] Work from our labs has shown that attaching four optoelectronic fragments to a tetrahedral point of convergence often results in amorphous materials [5] and that these can be used in the fabrication of light-emitting diodes (LEDs) with low turn-on voltages. [6] In all cases, the constituent ªarmº gives crystalline samples when cast out of solution, thereby limiting their use as the electroluminescent layer.…”

Section: Introductionmentioning

confidence: 99%

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A Tetrahedral Oligo(phenylenevinylene) Molecule of Intermediate Dimensions: Effect of Molecular Shape on the Morphology and Electroluminescence of Organic Glasses

et al. 2001

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Tetrakis[(4‐(4′‐(2″,5″‐dioctyloxy‐4″‐(4‴‐(2′‴,5′‴‐dioctyloxy‐4′‴‐styryl)styryl)styryl)styryl)styryl)phenyl]methane (T‐6R‐OC8H17) is an organic chromophore that consists of four optoelectronic fragments (“arms”) connected to a tetrahedral point of convergence (carbon). Bulk samples are amorphous as determined by powder diffraction, while differential scanning calorimetry (DSC) is sometimes ambiguous. Film forming properties were studied by atomic force microscopy (AFM) and fluorescence microscopy as a function of casting solvent and heat treatment. The film forming qualities are useful for the fabrication of light‐emitting diodes with low turn‐on voltages. Device performance is also history dependent. The relationship between bulk morphology, film topology, photoluminescence (PL) properties, and light‐emitting diode (LED) performance is discussed. A comparison of these compounds against the parent oligo(phenylenevinylene) arms, with respect to morphology, topology, and PL properties is also presented.

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Section: Methodsmentioning

confidence: 99%

Section: Synthesis and Characterizationmentioning

confidence: 99%

Section: Electroluminescencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Tetrahedral Oligo(phenylenevinylene) Molecule of Intermediate Dimensions: Effect of Molecular Shape on the Morphology and Electroluminescence of Organic Glasses

et al. 2001

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“…[3] Conducting polymers could, potentially, be used for secondary batteries, [4][5] media for erasable information storages, [6] electromagnetic shielding, [7][8] artificial muscles [9] and, also, new applications such as conducting polymer fibers, [9][10] light electroluminescence devices, [11][12] membranes for selective gas separations, [13][14][15][16] catalysts, biosensors and solar cells. [17] Polyanilines have been extensively studied as one of the attractive organic metals, due to their simple synthesis methods, various electrical properties and relatively high conductivities and thermal stabilities.…”

Section: Introductionmentioning

confidence: 99%

Control of Polyaniline Particle Shapes

Jung

Lee

et al. 2008

Macro Chemistry & Physics

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Needle‐like poly(aniline p‐toluenesulfonic acid) complex aggregates were synthesized by oxidative polymerization, yielding conductivities of up to 3 S · cm−1 and maximum aspect ratios of 26. Rod‐like aggregates as precursors to be developed into needle‐like aggregates were obtained with 1 to 2 h APS addition time at 15 °C. Flake‐like polyanilines were prepared at −2 or +20 °C with 1.9 to 2.5 h of APS addition time, giving aspect ratios of 2 to 10. Plate‐like polyaniline aggregates emerged when xylene was added, and an optimum xylene concentration was 15 vol.‐%, giving 1.3 S · cm−1 conductivity. The polyanilines were characterized by optical microscopy, SEM and UV‐vis/NIR spectroscopy.magnified image

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Glass-Forming Binaphthyl Chromophores

et al. 2001

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The use of the binaphthyl framework to synthesize glass-forming organic chromophores is described. Suzuki coupling reactions of racemic 6,6'-dibromo-2,2'-dialkoxy-1,1'-binaphthyl with 1,1-diphenyl-2-(4-dihydroxyboronphenyl)-ethene using [Pd(dppf)Cl2] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) as the catalyst provide a set of chromophores with the 4-(2,2'-diphenylvinyl)-1-phenyl group at the 6- and 6'-positions and a range of groups on the oxygen atom. Starting with enantiomerically enriched (R)-6,6'-dibromo-2,2'-dihexyloxy-1,1'-binaphthyl ((R)-2Hex), one can obtain (R)-3Hex. Heck coupling reactions of 6,6'-dibromo-2,2'-dialkoxy-1,1'-binaphthyl compounds with styrene provide chromophores of the type 2,2'-dialkoxy-1,1'-binaphthyl-6,6'-bis(2-phenyl-vinyl). Starting with enantiomerically enriched (R)-2Hex, one obtains (R)-4Hex. Molecules of the type 4 contain two 1-naphthyl-2-phenyl ethylene chromophores with a pseudoorthogonal relationship. Similar procedures can be used to obtain fragments with more extended conjugation length. Thus, the Heck coupling reaction of 2Hex with 4-(4'-tert-butylstyryl)styrene, 1-(4'-tert-butylstyryl)-4-(4'-vinylstyryl)benzene, and 1-(3',5'-dihexyloxystyryl)4-(4'-vinylstyryl)benzene provides 5Hex, 6Hex, and 7Hex, respectively. DSC measurements and powder diffraction experiments indicate that the binaphthol chromophores show a resistance to crystallization. In some cases, considerably different thermal behavior is observed between enantiomerically enriched samples and their racemic counterparts. Increasing the size of the conjugated fragment on the binaphthol core leads to materials with higher glass-transition temperatures and a less pronounced tendency to crystallize. Fluorescence spectroscopy gives evidence of "excimer"-type interactions in the solid state, except for the chromophores with 4-(2,2'-diphenylvinyl)-1-phenyl groups. It is possible to obtain amorphous films of these chromophores directly from solution, and to fabricate light-emitting diodes, in which the electroluminescent layer corresponds to the binaphthyl chromophore.

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Electroluminescence from Well-Defined Tetrahedral Oligophenylenevinylene Tetramers

Cited by 94 publications

References 9 publications

A Tetrahedral Oligo(phenylenevinylene) Molecule of Intermediate Dimensions: Effect of Molecular Shape on the Morphology and Electroluminescence of Organic Glasses

A Tetrahedral Oligo(phenylenevinylene) Molecule of Intermediate Dimensions: Effect of Molecular Shape on the Morphology and Electroluminescence of Organic Glasses

Control of Polyaniline Particle Shapes

Glass-Forming Binaphthyl Chromophores

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