Polyquinolines: Multifunctional Polymers for Electro-Optic and Light-Emitting Applications

1999 ◽  
Vol 558 ◽  
Author(s):  
Alex K.-Y. Jen ◽  
Hong Ma
Keyword(s):  
Electrical Characterization ◽  
Bright Light ◽  
Side Chain ◽  
Light Emitting ◽  
Electro Optic ◽  
Film Forming ◽  
Hole Transporting ◽  
Broad Variation ◽  
Nlo Chromophores ◽  
Multifunctional Polymers

ABSTRACTA versatile, and generally applicable modular approach for making second-order nonlinear optical (NLO) side-chain aromatic polyquinolines has been developed. This approach emphasizes the ease of incorporating NLO chromophores onto the pendent phenyl moieties of parent polyquinolines at the final stage via mild Mitsunobu reaction. This method provides the synthesis of polyquinolines with a broad variation of the polymer backbones and great flexibility in the selection of NLO chromophores. These side-chain NLO polyquinolines demonstrate high electro-optic (E-O) activity (up to 35 pm/V at 830 nm and 22 pm/V at 1300 nm, respectively) and a good combination of thermal, optical, electrical and mechanical properties.Comparatively, two new electroluminescent (EL) polyquinolines have been prepared via the Friedlander condensation and nucleophilic reaction. The resulting polymers contain a bipolar property with both an efficient hole-transporting moiety, tetraphenyldiaminobiphenyl (TPD), and an electron affinitive light-emitting moiety, bis-quinoline. In addition, they possess high thermal stability, excellent electrochemical reversibility, good thin film-forming ability, and bright light-emitting property. Electrical characterization of two-layer diode devices based on the configurations of ITO/CuPc/TPD-PQ or TPD-PQE/Al showed excellent electroluminescence performance (a rectification ratio greater than 105 and a low turn-on voltage of less than 4 V).

Light-Emitting and Hole-Transporting Polymers for LEDs

1997 ◽  
Vol 488 ◽  
Author(s):  
Toshihiro Ohnishi ◽  
Shuji Doi ◽  
Masato Ueda ◽  
Fumi Yamaguchi ◽  
Takanobu Noguchi
Keyword(s):  
High Efficiency ◽  
Hole Mobility ◽  
Hole Injection ◽  
Side Chain ◽  
High Luminance ◽  
Strong Fluorescence ◽  
Light Emitting ◽  
Hole Transporting ◽  
Hole Transporting Material ◽  
Injection Barrier

AbstractVarious copolymers of arylene vinylenes, having strong fluorescence, showed predominantly the emission in the multi-layer device using an electron-transporting material(ETM) such as tris(8-quinolinolato)aluminum(Alq3). The emission from Alq3 was suppressed due to the high hole-injection barrier from the copolymers to ETM in spite of low or no barriers of electron injection from ETM to the copolymers. We have successfully prepared highly hole-transporting polysilane having a triphenylamine group as a side chain(TPA-PS). The hole mobility as high as 10 cm3cm2/Vs is attributable to the intermolecular hopping process facilitated by the interaction between the polysilane backbone and the triphenylamine group. The polysilane is effectively used as a hole transporting material. The bilayer LED device consisting of TPA-PS and Akb3 showed high luminance (2000cd/m2) and high efficiency (4cd/A).

Synthesis of Carbazole-Based Polymers with 1,3,4-Oxadiazole Pendant Group and Their Application in Organic Light-Emitting Diodes

2008 ◽  
Vol 8 (9) ◽  
pp. 4846-4850
Author(s):  
Hui Wang ◽  
Jeong-Tak Ryu ◽  
Chao Cao ◽  
Younghwan Kwon
Keyword(s):  
Light Emitting Diodes ◽  
Band Gap Energy ◽  
Side Chain ◽  
Visible Absorption ◽  
Homo Energy ◽  
Light Emitting ◽  
Hole Transporting ◽  
Palladium Catalyzed ◽  
Polymer Light Emitting Diodes ◽  
Uv Visible

Structurally well-defined copolymers with high solubility were prepared via palladium-catalyzed polycondensation of N-(2-ethylhexyl)-3,6-dibromocarbazole with 2-aryl-5-(4-aminophenyl)-1,3,4-oxadiazole (aryl = phenyl, p-methylphenyl, p-methoxyphenyl). Copolymers consisted of alkylcarbazole groups in the main chain and 1,3,4-oxadiazole pendants in the side chain. The influence of their aryl substituents on physical, optical, band gaps and electroluminescent characteristics of the copolymers was investigated. Both UV-Visible absorption and photoluminescence emission peaks of the copolymers were similar to each other. The band gap energy of the polymers was measured in the range of 2.84∼2.88 eV, and HOMO energy in the range of −5.13∼−5.18 eV. These copolymers were used as hole-transporting layers (HTL) in the light-emitting diodes with Alq3 as an emitting layer. Compared to devices with P-H and P-OCH3 used as HTL, it should be noted that device with P-CH3 used as HTL showed higher luminescence. Maximum luminescence of devices was measured to be 276cd/m2 at 14 V with P-H, 625 cd/m2 at 15 V with P-CH3, and 471 cd/m2 at 14 V with P-OCH3. This might be due to effect of subtle changes in HOMO energy level of polymers with changing substituent groups. Phosphorescent polymer light emitting diodes were also fabricated with an emitting layer consisting of P-CH3 matrix and a red phosphorescent dopant (Ir-PIQCH).

High Performance Side-Chain Polyquinolines and Perfluorocyclobutane-Containing Thermoset Polymers for Electro-Optic Applications

1999 ◽  
Vol 598 ◽  
Author(s):  
Hong Ma ◽  
Jianyao Wu ◽  
Petra Herguth ◽  
Baoquan Chen ◽  
Ajay Purohit ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Cycloaddition Reaction ◽  
Second Order ◽  
Side Chain ◽  
Crosslinking Reaction ◽  
Modular Approach ◽  
Electro Optic ◽  
Wide Range ◽  
Thermoset Polymers ◽  
Nlo Chromophores

ABSTRACTA modular approach for making second-order nonlinear optical (NLO) side-chain aromatic polyquinolines has been developed. The synthesis provides a method for readily incorporating NLO chromophores into the pendent phenyl moieties of parent polyquinolines at the final stage via the Mitsunobu reaction. The method produces polyquinolines with a wide range of polymer backbones and offers great flexibility in the selection of NLO chromophores. These side-chain NLO polyquinolines demonstrate high electro-optic (E-O) activities (up to 35 pm/V at 830 nm and 22 pm/V at 1300 nm) and excellent tradeoffs among thermal, optical, and electrical properties.Most recently, a series of novel second-order NLO thermoset polymers containing silicon-perfluorocyclobutane (PFCB) has also been synthesized. This was accomplished via the crosslinking reaction between the di(trifluorovinylether)-containing NLO chromophores and the tris(trifluorovinylether) monomer in solid state at 180-250 °C. The radical-mediated, stepwise cycloaddition reaction offers great tolerance to very sensitive functional groups such as tricyanovinyl acceptor. A variety of NLO chromophores could be easily incorporated into these thermoset polymers compared to the modular approach. Preliminary results have indicated these polymers to possess excellent processability, low optical loss, and a combination of highly desirable thermal, nonlinear optical, and mechanical properties.

Charged Iridium(III) Complexes with Varied Side Chain Length in Organic Light Emitting Diodes

2017 ◽  
Vol 751 ◽  
pp. 500-506
Author(s):  
Natsiri Wongsang ◽  
Kittiya Wongkhan ◽  
Laongdao Kangkeaw ◽  
Somboon Sahasitthiwat ◽  
Rukkiat Jitchati
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Side Chain ◽  
Light Emitting ◽  
Alkyl Chains ◽  
The Core ◽  
Organic Light ◽  
Film Forming ◽  
Maximum Current ◽  
Π Stacking Interaction

The four varied side chains of charged iridium(III) complexes were synthesized and characterized for organic light emitting diodes. The core materials were designed with 9,9-bis(4-methoxyphenyl)-4,5-diazafluorene as the bulky N^N ligand which prevent the π-π stacking interaction in the solid state. Their photophysical and electrochemical properties were investigated. OLEDs were fabricated with the structure ITO/PEDOT:PSS/ PVK:complex (10:7 by weight)/ TPBi/LiF/Al. The similar colors were obtained with varied OLEDs performances. We concluded that the long alkyl chains affected to the excellent film-forming property of emitting layer. Therefore, the device based on the n-octyl chain namely [(9,9-bis(4-octyloxyphenyl)-9H-cyclopentadipyridine-N-N′)-bis-(2-phenylpyridine-C2′,N)-iridium(III)] haxafluorophosphate (C8) showed the maximum current efficiency and brightness of 11.37 cd/A and 3,926 cd/m2, respectively.

Controlled Injection of Holes into ALQ3 Based Oleds by Means of An Oxidized Transport Layer

2001 ◽  
Vol 708 ◽  
Author(s):  
Mathew K. Mathai ◽  
Keith A. Higginson ◽  
Bing R. Hsieh ◽  
Fotios Papadimitrakopoulos
Keyword(s):  
Indium Tin Oxide ◽  
Oxidative Degradation ◽  
Transport Layer ◽  
Hole Injection ◽  
Carrier Injection ◽  
Salt Loading ◽  
Light Emitting ◽  
Hole Transporting ◽  
Intrinsic Degradation ◽  
Variable Conductivity

ABSTRACTIn this paper we report a method for tuning the extent of hole injection into the active light emitting tris- (8-hydroxyquinoline) aluminum (Alq3) layer in organic light emitting diodes (OLEDs). This is made possible by modifying the indium tin oxide (ITO) anode with an oxidized transport layer (OTL) comprising a hole transporting polycarbonate of N,N'-bis(3-hydroxymethyl)-N,N'-bis(phenyl) benzidine and diethylene glycol (PC-TPB-DEG) doped with varying concentrations of antimonium hexafluoride salt of N,N,N',N'-tetra-p-tolyl-4,4'-biphenyldiamine (TMTPD+ SbF6-). The conductivity of the OTL can be changed over three orders of magnitude depending on salt loading. The analysis of hole and electron current variations in these devices indicates that optimizing the conductivity of the OTL enables the modulation of hole injection into the Alq3 layer. The bipolar charge transport properties for OLEDs in which the interfacial carrier injection barriers have been minimized, are governed by the conductivities of the respective layers and in this case it is shown that the variable conductivity of the OTL does allow for better control of the same. Accordingly, varying the concentration of holes in the device indicates that beyond an optimum concentration of holes, further hole injection results in the formation of light quenching cationic species and the initiation of oxidative degradation processes in the Alq3 layer, thus accelerating the intrinsic degradation of these devices. The variable conductivity of the OTL can hence be used to minimize the occurrence of these processes.

Sulfonamides Are an Overlooked Class of Electron Donors in Luminogenic Luciferins and Fluorescent Dyes

2018 ◽  
Author(s):  
Deepak K. Sharma ◽  
Spencer T. Adams ◽  
Kate L. Liebmann ◽  
Adam Choi ◽  
Stephen Miller
Keyword(s):  
Fluorescent Dyes ◽  
Bright Light ◽  
Firefly Luciferase ◽  
Electron Donors ◽  
Light Emitting

Many fluorophores, and all bright light-emitting substrates for firefly luciferase, contain hydroxyl or amine electron donors. Here we show that sulfonamides can serve as replacements for these canonical groups. Unlike “caged” carboxamides, sulfonamide analogues enable bioluminescence, and sulfonamidyl luciferins, coumarins, rhodols, and rhodamines are fluorescent in water. Sulfonamide donors thus have previously unappreciated potential to expand the functional repertoire of luminescent molecules.

scholarly journals High efficiency blue organic light-emitting diodes with below-bandgap electroluminescence

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maria Vasilopoulou ◽  
Abd. Rashid bin Mohd Yusoff ◽  
Matyas Daboczi ◽  
Julio Conforto ◽  
Anderson Emanuel Ximim Gavim ◽  
...  
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
High Mobility ◽  
Organic Light Emitting Diodes ◽  
Triplet Energy ◽  
Material Interface ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Hole Transporting

AbstractBlue organic light-emitting diodes require high triplet interlayer materials, which induce large energetic barriers at the interfaces resulting in high device voltages and reduced efficiencies. Here, we alleviate this issue by designing a low triplet energy hole transporting interlayer with high mobility, combined with an interface exciplex that confines excitons at the emissive layer/electron transporting material interface. As a result, blue thermally activated delay fluorescent organic light-emitting diodes with a below-bandgap turn-on voltage of 2.5 V and an external quantum efficiency (EQE) of 41.2% were successfully fabricated. These devices also showed suppressed efficiency roll-off maintaining an EQE of 34.8% at 1000 cd m−2. Our approach paves the way for further progress through exploring alternative device engineering approaches instead of only focusing on the demanding synthesis of organic compounds with complex structures.

An Efficient Hole Transporting Polymer for Quantum Dot Light‐Emitting Diodes

2021 ◽  
pp. 2100731
Author(s):  
Wenhai Wu ◽  
Zhao Chen ◽  
Yunfeng Zhan ◽  
Bochen Liu ◽  
Weidong Song ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Hole Transporting

Bis(4-diphenylaminophenyl)carbazole end-capped fluorene as solution-processed deep-blue light-emitting and hole-transporting materials for electroluminescent devices

2012 ◽  
Vol 53 (28) ◽  
pp. 3615-3618 ◽  
Author(s):  
Daungratchaneekron Meunmart ◽  
Narid Prachumrak ◽  
Tinnagon Keawin ◽  
Siriporn Jungsuttiwong ◽  
Taweesak Sudyoadsuk ◽  
...  
Keyword(s):  
Blue Light ◽  
Solution Processed ◽  
Electroluminescent Devices ◽  
Light Emitting ◽  
Deep Blue ◽  
Hole Transporting ◽  
Hole Transporting Materials
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