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Maximum Luminance (maximum + luminance)

Distribution by Scientific Domains

Polymers and Materials Science	85%

Selected Abstracts

Multifunctional Fluorene-Based Oligomers with Novel Spiro-Annulated Triarylamine: Efficient, Stable Deep-Blue Electroluminescence, Good Hole Injection, and Transporting Materials with Very High Tg

ADVANCED FUNCTIONAL MATERIALS, Issue 24 2009
Zuoquan Jiang
Abstract A series of fluorene-based oligomers with novel spiro-annulated triarylamine structures, namely DFSTPA, TFSTPA, and TFSDTC, are synthesized by a Suzuki cross-coupling reaction. The spiro-configuration molecular structures lead to very high glass transition temperatures (197,253,°C) and weak intermolecular interactions, and consequently the structures retain good morphological stability and high fluorescence quantum efficiencies(0.69,0.98). This molecular design simultaneously solves the spectral stability problems and hole-injection and transport issues for fluorene-based blue-light-emitting materials. Simple double-layer electroluminescence (EL) devices with a configuration of ITO/TFSTPA (device A) or TFSDTC (device B)/ TPBI/LiF/Al, where TFSTPA and TFSDTC serve as hole-transporting blue-light-emitting materials, show a deep-blue emission with a peak around 432,nm, and CIE coordinates of (0.17, 0.12) for TFSTPA and (0.16, 0.07) for TFSDTC, respectively, which are very close to the National Television System Committee (NTSC) standard for blue (0.15, 0.07). The maximum current efficiency/external quantum efficiencies are 1.63,cd A,1/1.6% for device A and 1.91,cd A,1/2.7% for device B, respectively. In addition, a device with the structure ITO/DFSTPA/Alq3/LiF/Al, where DFSTPA acts as both the hole-injection and -transporting material, is shown to achieve a good performance, with a maximum luminance of 14,047,cd m,2, and a maximum current efficiency of 5.56,cd A,1. These values are significantly higher than those of devices based on commonly usedN,N,-di(1-naphthyl)- N,N,-diphenyl-[1,1,-biphenyl]-4,4,-diamine (NPB) as the hole-transporting layer (11,738,cd m,2 and 3.97,cd A,1) under identical device conditions. [source]

Synthesis and characterization of novel poly(arylenevinylene) derivative

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008
Song Se-Yong
Abstract The new poly(arylenevinylene) derivative composed naphthalene phenylene vinylene backbone was developed. The theoretical calculation showed that the model compound of the obtained polymer was highly distorted between the stryl and naphthalene units as well as between the backbone and fluorene side units. The polymer was synthesized by the palladium catalyzed Suzuki coupling reaction with 2,6-(1,,2,-ethylborate)-1,5-dihexyloxynaphtalene and 1,2-bis(4,-bromophenyl)-1-(9,,9,-dihexyl-3-fluorenyl)ethene. The structure of the polymer was confirmed by 1H NMR, IR, and elemental analysis. The weight,average molecular weight of the polymer is 29,800 with the polydispersity index of 1.87. The new polymer showed good thermal stability with high Tg of 195°C. The bright blue fluorescence (,max = 475 nm) was observed both in solution and film of new polymer with naphthalene phenylene vinylene backbone. Double layer LED devices with the configuration of ITO/PEDOT/polymer/LiF/Ca/Al showed a turn-on voltage at around 4.5 V, the maximum luminance of 150 cd/m2, and the maximum efficiency of 0.1 cd/A. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Immiscible polymers in double spin-coated electroluminescent devices containing phenyl-substituted tris(8-hydroxyquinoline)aluminum derivatives soluble in a host polymer

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2003
E. Shoji
Abstract Three new phenyl-substituted tris(8-hydroxyquinoline)aluminum (AlQ3) derivatives have been synthesized: tris(5-phenyl-8-quinolinolate-N1,O8)aluminum, tris(5,7-diphenyl-8-quinolinolate-N1,O8)aluminum, and tris[5,7-bis(p -fluorophenyl)-8-quinolinolate-N1,O8]aluminum. These AlQ3 derivatives are easily soluble in common organic solvents and form solid-phase solutions in a poly(aryl ether ketone) host polymer (A435). These interesting properties allow the use of soluble AlQ3 derivatives in double spin-coated organic light-emitting devices of the type ITO/NPB-QP/A435 + 50 wt % soluble AlQ3 derivative/Mg, where NPB-QP is a hole-transporting polymer insoluble in toluene, the solvent for A435. Typical double spin-coated organic layer devices are characterized by an emission at 530,539 nm, a threshold voltage of 6,9 V, and a maximum luminance of 1800,4000 cd/m2 at 21,25 V. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3006,3016, 2003 [source]

Design and Synthesis of Phosphorescent Iridium Containing Dendrimers for Potential Applications in Organic Light-Emitting Diodes,

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 18 2008
Qin-De Liu
Abstract Three phosphorescent dendrimers (IrC1, IrC3, and IrF2) with an iridium complex core and oligocarbazole or oligofluorene substituted ligands were synthesized and characterized. The structures of the oligocarbazole were designed to maintain high triplet energy of the ligands so that phosphorescence quenching in the resulting dendrimers can be prevented, while the oligofluorene in IrF2 resulted in undesired phosphorescence quenching. Best performance was obtained from an IrC3 based electrophosphorescent light-emitting device with a maximum luminance of 13,060 cd,·,m,2 at a driving voltage of 11.5 V and a peak current-efficiency of 4.3 cd,·,A,1 at a luminance of 3,400 cd,·,m,2, owing to its high PL efficiency, and efficient energy transfer between the iridium complex core and the ligands. [source]

Synthesis, characterization, and electroluminescence of new conjugated PPV derivatives bearing triphenylamine side-chain through a vinylene bridge

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2007
Zhan'ao Tan
Abstract Three new conjugated poly(p -phenylene vinylene) (PPV) derivatives bearing triphenylamine side-chain through a vinylene bridge, poly(2-(4,-(diphenylamino)phenylenevinyl)-1,4-phenylene-vinylene) (DP-PPV), poly(2-(3,-(3,,7,-dimethyloctyloxy)phenyl)-1,4-phenylenevinylene- alt -2-(4,- (diphenylamino)phenylenevinyl)-1,4-phenylenevinylene) (DODP-PPV), and poly(2-(4,-(diphenylamino)phenylenevinyl)-1,4-phenylenevinylene-co-2-(3,,5,-bis(3,,7,-dimethyloctyloxy)-1,4-phenylenevinylene) (DP-co-BD-PPV), were synthesized according to the Gilch or Wittig method. Among the three polymers, the copolymer DP-co-BD-PPV is soluble in common solvents with good thermal stability with 5% weight loss at temperatures higher than 386°C. The weight-average molecular weight (Mw) and polydispersity index (PDI) of DP-co-BD-PPV were 1.83,×,105 and 2.33, respectively. The single-layer polymer light-emitting diodes (PLEDs) with the configuration of Indium tin oxide (ITO)/poly (3,4-ethylenedioxythiophene): poly(4-styrene sulfonate)(PEDOT:PSS)/DP-co-BD-PPV/Ca/Al were fabricated. The PLED emitted yellow-green light with the turn-on voltage of ca. 4.9,V, the maximum luminance of ca. 990,cd/m2 at 15.8,V, and the maximum electroluminescence (EL) efficiency of 0.22,cd/A. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Diphenylamino End-Capped Oligofluorenes with Enhanced Functional Properties for Blue Light Emission: Synthesis and Structure,Property Relationships

CHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2005
Zhong Hui Li
Abstract A novel series of monodisperse asymmetrically and symmetrically substituted diphenylamino end-capped oligofluorenes, OF(2)-NPhR, R = H or An (An = 9-anthryl) and OF(n)-NPh, n = 2,4, has been synthesized by a convergent approach using palladium-catalyzed Suzuki cross-coupling. End-capping of oligofluorenes with diphenylamino group(s) has been shown to offer advantages in terms of lowering their first ionization potentials, enhancing thermal stability, and inducing good amorphous morphological stability. By tuning the number of diphenylamino end-caps and the chain length, the optimal conjugated length for optical and luminescence properties has been determined. Of all the hitherto reported oligofluorenes capable of serving as non-doped blue emitters, OF(3)-NPh, with an optimal conjugated length, exhibits some of the best hole-transport and blue-emitting properties. A maximum luminance of 7500 cd,m,2 and a luminance efficiency up to 1.8 cd,A,1 have been achieved. [source]

Charge-Transporting Polymers based on Phenylbenzoimidazole Moieties

ADVANCED FUNCTIONAL MATERIALS, Issue 3 2010
Marc Debeaux
Abstract A series of novel styrene functionalized monomers with phenylbenzo[d]imidazole units and the corresponding homopolymers are prepared. These side-chain polymers show high glass-transition temperatures that even exceed the corresponding value for the common electron-transporting material 1,3,5-tris(1-phenyl-1H -benzo[d]imidazol-2-yl)benzene (TPBI). Similar electronic behavior between the polymers and TPBI is shown. The polymers are used as matrices for phosphorescent dopants. The fabricated devices exhibit current efficiencies up to 38.5,cd A,1 at 100,cd,m,2 and maximum luminances of 7400,cd m,2 at 10,V with a minimum turn-on voltage as low as 2.70,V in single-layer devices with an ITO/PEDOT:PSS anode (ITO,=,indium tin oxide, PEDOT:PSS,=,poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate)) and a CsF/Ca/Ag cathode. [source]