Blue electroluminescence in blend of polymers containing carbazole and 1,3,4-oxadiazole units

Jin, Sung‐Ho; Kim, Woo-Hong; Song, In-Sung; Kwon, Soon‐Ki; Lee, Kwang-Sik; Han, Eun‐Mi

doi:10.1016/s0040-6090(99)01070-6

Cited by 31 publications

(18 citation statements)

References 6 publications

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“…They effectively prevent the crystallization or aggregation of the small molecules [2]. The blend compositions containing mixtures of electron transporting and emitting materials are often used to fabricate efficient single-layer devices with high quantum efficiencies [3,4]. Kido et al [5] demonstrated that molecularly doped polymers provide a high flexibility in designing EL devices, in which poly(9-vinylcarbazole) (PVK) was used both as a matrix and as a hole transport material.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Energy Transfer in a Blend of electroluminescent Conducting Polymers

Định¹,

Nam²,

Chung³

2011

Comm. in Phys.

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Abstract. With the aim of improving the photonic efficiency of an organic light emitting diode a blend of electroluminescent polymers, poly [9-vinylcarbarzole] (PVK) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) was prepared. The energy transfer in the blend was investigated through the comparison of absorption, photoluminescence (PL) and currentvoltage (I-V) characteristics of the blend and standard polymers. The obtained results showed that energy transfer from PVK to MEH-PPV enable to form localized excited-state complexes (e.g. exciplexes) in MEH-PPV. The PL intensity of the blended polymers was enhanced as the relative content of MEH-PPV was increased, and particularly, the highest improved PL was observed for an weight fraction of 15 wt% of MEH-PPV in PVK. Organic light emitting diodes made from these blends would exhibit a large photonic efficiency.

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Section: Introductionmentioning

confidence: 99%

Investigation of Energy Transfer in a Blend of electroluminescent Conducting Polymers

Định¹,

Nam²,

Chung³

2011

Comm. in Phys.

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“…14 Therefore, the development of P3AT derivatives with improved electron injection and transporting capability and a balance in the injection of electrons and holes into the emissive layers is necessary to obtain high-efficiency polymer light-emitting diode devices. 15 Materials, such as 1,3,4-oxadiazole or pyridine, with an electron-deficient heteroaromatic ring always have lower barriers for electron injection from metal cathodes. 16 Thus, copolymers containing 1,3,4-oxadiazole or pyridine in the main chain or in the side groups have been found to be very efficient for increasing electron affinity and, therefore, enhancing their electron-transporting properties.…”

Section: Introductionmentioning

confidence: 99%

Novel 2,4‐divinyl‐3‐alkylthiophene/1,3,4‐oxadiazole alternating conjugated copolymer synthesized by the Heck coupling method: Synthesis, characterization, and electronic and optical properties

Wei

Chen

et al. 2010

J of Applied Polymer Sci

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A novel alternating copolymer with 3-alkylthiophene and oxadiazole (or pyridine) units in ordered arrangement was synthesized with vinyl as a bridge for the first time. The synthesis process included four steps: bromomethylation, preparation of the ylide monomer, the formation of 2,4-divinyl-3-alkylthiophene, and Heck alternating copolymerization. The Fourier transform infrared spectroscopy, 1 H-NMR, and gel permeation chromatography measurements showed that all of the copolymers had the required structures. The weight-average molecular weights of the copolymers were in the range 5500-15,000 with a relatively low polydispersity index of 1.4-1.7. The solubility of the copolymers in common solvents (e.g., methylene chloride, chloroform, tetrahydrofuran) was excellent. The optical properties and bandgap of the copolymers was compared with corresponding poly(3-alkylthiophene) homopolymers. The photoluminescence quantum efficiency (QE) of the copolymers improved markedly in chloroform. The QEs of poly(2,4-divinyl-3-hexylthiophene-alt-2,5-diphenyl-1,3,4-oxadiazole) and poly(2,4-divinyl-3-octythiophene-alt-2,5-diphenyl-1,3,4-oxadiazole) were 43.2 and 34.2%, respectively, which were about 20 and 21 times higher than those of the homopolymers, respectively. The ionization potential of the copolymers between 5.53 and 6.13 eV was appropriated to poly(3-alkylthiophene)s. The high electron affinity of the copolymers (2.71-2.95 eV) made the electrons inject from the cathode more easily. With excellent solubility, low bandgap energy, high QE, and both electron-transporting and hole-transporting abilities, the proposed copolymers might be excellent polymeric materials for applications in polymer light-emitting diodes, light-emitting electrochemical cells, and polymer solar cells.

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“…In our previous publications, we reported the synthesis and characterization of several novel electroluminescent (EL) polymers, including alkylsilylphenyl‐ and alkyloxyphenoxy‐substituted poly(p‐phenylenevinylene)s (PPVs), blend systems with oxadiazole‐containing electron transfer polymers, and the synthesis of alternating copolymers composed of PPV segments and aromatic amine blocks 15–21. More recently, we reported the EL properties of the highly efficient poly(9,9‐dioctylfluorenyl‐2,7‐vinylene) and its copolymers with various feed ratios of poly[2‐methoxy‐5‐(2'‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) units,22, 23 and those of PPV with pendant 1,3,4‐oxadiazole and propylenedioxythiophene derivatives obtained with the Gilch polymerization method 24, 25.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of fluorene‐based copolymers containing benzothiadiazole derivative for light‐emitting diodes applications

Yoon

Park

Lee

et al. 2008

J. Polym. Sci. A Polym. Chem.

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Five new thermally robust electroluminescent fluorene-based conjugated copolymers, including poly[2,7-(9,9-dioctylfluorene)-co-4,7-{5,6-bis(3,7-dimethyloctyloxymethyl)-2,1,3-(benzothiadiazole)}] (PFO-P2C 10 BT) were synthesized and used to fabricate the efficient polymer light-emitting diodes (PLEDs). The glass transition temperatures of the polymers were found to be higher than that of poly(9,9-dialkylfluorenes) and are in the range 113-165 C. We fabricated PLEDs in indium-tin oxide/ PEDOT/light-emitting polymer/cathode configurations using either double-layer LiF/Al or triple-layer Alq 3 /LiF/Al cathode structures. The new copolymers were found to have emission colors that vary from greenish blue (491 nm) to green (543 nm) depending on the copolymer composition. The maximum brightness and luminance efficiency of these PLEDs were found to be up to 5347 cd/m 2 and 1.51 cd/A at 10 V, respectively. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: [6762][6763][6764][6765][6766][6767][6768][6769] 2008

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Blue electroluminescence in blend of polymers containing carbazole and 1,3,4-oxadiazole units

Cited by 31 publications

References 6 publications

Investigation of Energy Transfer in a Blend of electroluminescent Conducting Polymers

Investigation of Energy Transfer in a Blend of electroluminescent Conducting Polymers

Novel 2,4‐divinyl‐3‐alkylthiophene/1,3,4‐oxadiazole alternating conjugated copolymer synthesized by the Heck coupling method: Synthesis, characterization, and electronic and optical properties

Synthesis and characterization of fluorene‐based copolymers containing benzothiadiazole derivative for light‐emitting diodes applications

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