Synthesis and Characterization of Aromatic Poly(1,3,5-triazine−ether)s for Electroluminescent Devices

Fink, Ralf; Frenz, Carsten; Thelakkat, Mukundan; Schmidt, Hans‐Werner

doi:10.1021/ma970528x

Cited by 124 publications

(88 citation statements)

References 16 publications

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“…The reaction was carried out in diphenylsulfone or NMP in the presence of potassium carbonate at 190 8C, using toluene to remove water by azeotropic distillation [32,33]. Synthesis of the poly-(quinoxaline ether) (p-QUX) and the monomers 1 and 2 were carried out according to the literature [25,34,35]. The HBETL polymers were characterized by NMR, FTIR spectroscopy and UV/vis and fluorescence spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

A comparison of hole blocking/electron transport polymers in organic LEDs

et al. 1998

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Three main‐chain aromatic polyethers with different electroactive heterocyclic moieties, 1,4‐quinoxaline, 1,3,4‐oxadiazole and 1,3,5‐triazine, have been synthesized. The polymers are amorphous with glass transition temperatures above 200°C. The polymers with these high electron affinity units were used as hole blocking/electron transport layers (HBETL) in light‐emitting diodes (LEDs) having the HBETL casted on top of a hole transport/emitting PPV layer. In order to compare the influence of the different polyethers on the LED characteristics, three multilayer devices (ITO/PPV/HBETL/Al) with different HBETLs were investigated. Relative to the single layer PPV device, quantum efficiencies were improved by two orders of magnitude in all multilayer devices and power efficiency was increased using poly(quinoxaline ether) as HBETL. To investigate the electrochemical behavior of the three HBETLs, cyclic voltammetry measurements were carried out and the HOMO/LUMO energy values determined from redox potentials were used to understand the hole blocking property. Lowering the onset voltage using the poly(quinoxaline ether) as HBETL in two‐layer devices is compatible with the high electron affinity of this polymer.

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Section: Resultsmentioning

confidence: 99%

A comparison of hole blocking/electron transport polymers in organic LEDs

et al. 1998

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“…Its most representative derivative is 3-(4-biphenyl)-4-phenyl-5-(49-tert-butylphenyl)1,2,4-triazole (TAZ, 86), which is not only a good electron-transporting material but also a better hole-blocking material than PBD [188]. Although 1,3,4-oxadiazoles and 1,2,4-triazoles are the most widely used electron-transporting materials, other materials containing electron-deficient quinoxalines (88) [19] and triazines (89) [19,189] among others have also been used as ETLs.…”

Section: Low Molecular Weight Electroluminescent Materialsmentioning

confidence: 99%

The chemistry of electroluminescent organic materials

Segura¹

1998

Acta Polym.

287

200

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Electroluminescence has been a subject of interest for several decades because of its many applications in areas such as telecommunications or information displays. Light‐emitting diodes using p‐n junctions of inorganic semiconductors have dominated the field in the last twenty years; however, efficient blue emission has only recently been achieved and inorganic semiconductors are difficult to form over large areas, making the process uneconomic. During the last decade, an explosive growth of activity in the area of organic electroluminescence has occurred in both academia and industry, stimulated by the promise of light‐emitting plastics for the fabrication of large, flexible, inexpensive and efficient screens to be used in different applications. Thus, a substantial amount of research is presently directed towards color control and improvement of manufacturability and reliability of devices in order to make their commercialization viable. A great deal of work has been carried out by physicists and materials scientists concerned with the preparation of different device structures and with the use of different techniques for device manufacture. However, all this work would not be possible without the continuous efforts of synthetic chemists to prepare materials with enhanced luminescent properties and processabilities. This article provides a review of the main types of organic materials that have been used in the fabrica‐tion of light‐emitting diodes either as emitting materials or as charge‐transport layers. Special attention will be paid to the different synthetic strategies that have been followed in order to tune the color of the emission, to increase stability of materials and to enhance their processabilities.

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“…[28] 1,3,5-Triazine is an electron-deficient group with high electron-affinity, [29] which is higher than that of oxadiazole. Hence, by introducing triazine into PFs, the electron injection and transport properties are improved.…”

Section: Hyperbranched Polyfluorenesmentioning

confidence: 99%

Polyfluorene‐Based Blue‐Emitting Materials

Zhao

Liu

Huang

2009

Macro Chemistry & Physics

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Polyfluorenes are a class of promising blue light‐emitting conjugated polymer due to their excellent optoelectronic properties. However, the applications of polyfluorenes in polymer light‐emitting diodes (PLEDs) have been hampered by the appearance of long‐wavelength green emission, leading to the problem of color purity and stability. Hence, the preparation of pure blue‐emitting polyfluorenes becomes very important for the realization of real blue‐emitting PLEDs. In this short review, we introduce the efforts made by our group to realize polyfluorenes with pure blue emission, including the incorporation of spirobifluorene units, heterofluorene units, hyperbranched, and star‐shaped structures into polymer backbones.

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Synthesis and Characterization of Aromatic Poly(1,3,5-triazine−ether)s for Electroluminescent Devices

Cited by 124 publications

References 16 publications

A comparison of hole blocking/electron transport polymers in organic LEDs

A comparison of hole blocking/electron transport polymers in organic LEDs

The chemistry of electroluminescent organic materials

Polyfluorene‐Based Blue‐Emitting Materials

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