Electroluminescence Properties of Systematically Derivatized Organic Chromophores Containing Electron Donor and Acceptor Groups

Patra, Amitava; Pan, Michael; Friend, Christopher S.; Lin, Tzu Chau; Cartwright, and Alexander N.; Prasad, Paras N.; Burzyński, Ryszard

doi:10.1021/cm020075x

Cited by 49 publications

(34 citation statements)

References 23 publications

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“…This is because TPA has a HOMO level that is higher than PVK and a LUMO level that is lower than PVK, which decreases the energy barriers for hole and electron injection, and provides an effective, higher-lying HOMO pathway to transport holes, and a lowerlying LUMO pathway to transport electrons. [37] This point is supported by the decreased turn-on voltage ( Table 2) and increased current densities (Fig. 7) observed in device V. Secondly, TPA may act as a relay to promote singlet-exciton transfer from the PVK host to the MBIN dopant.…”

Section: Full Papermentioning

confidence: 73%

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

et al. 2006

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Three new starburst DCM (4‐(dicyanomethylene)‐2‐methyl‐6‐[4‐(dimethylaminostyryl)‐4H‐pyran]) derivatives, 4,4′,4′′‐tris[2‐(4‐dicyanomethylene‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (TDCM), 4,4′,′′‐tris[2‐(4‐(1′,3′‐indandione)‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (TIN), and 4‐methoxy‐4′,4′′‐bis[2‐(4‐(1′,3′‐indandione)‐6‐t‐butyl‐4H‐pyran‐2‐yl)‐ethylene]triphenylamine (MBIN), have been designed and synthesized for application as red‐light emitters in organic light‐emitting diodes (OLEDs). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) reveal their extremely high glass‐transition temperatures and decomposition temperatures, as well as their low tendency to crystallize. Photoluminescence and electroluminescence measurements show that they exhibit a greatly restricted concentration‐quenching effect compared to DCM1 (4‐(dicyanomethylene)‐2‐methyl‐6‐[p‐(N,N‐dimethylamino)‐styryl]‐4H‐pyran), a simple but typical DCM‐type dye, as a result of their non‐planar, three‐dimensional structures that result from their unique propeller‐like triphenylamine electron‐donating cores. The peripheral electron‐withdrawing moieties also play a key role in the restriction of concentration quenching. That is, TIN and MBIN, bearing 1,3‐indandione acceptors, emit more efficiently than TDCM and DCM1, which have dicyanomethylene as acceptors at a high doping concentration of 10 wt.‐% in poly(9‐vinylcarbazole) (PVK) film, irrespective of whether they are photoexcited or electroexcited, though their fluorescence quantum yields in dilute solutions are much lower than that of DCM1. By way of the co‐doping approach, the electroluminescence device with the configuration indium tin oxide (ITO)/PVK:MBIN(10 wt.‐%):tris(4‐(2‐phenylethynyl)‐phenyl)amine (TPA; 30 wt.‐%) (70 nm)/2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline (BCP; 20 nm)/tris(8‐quinolinolato) aluminum (Alq3;15 nm)/LiF (0.3 nm)/Al (150 nm) exhibits a turn‐on voltage of 5.1 V, a maximum luminance of 6971 cd m–2, a maximum efficiency of 6.14 cd A–1 (405 cd m–2), and chromaticity coordinates of (0.66,0.33). The encouraging electroluminescence performance suggests potential applications of the starburst DCM red‐light emitters in OLEDs.

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Section: Full Papermentioning

confidence: 73%

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

et al. 2006

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“…Recently, Patra et al reported that the molecular architectures consisting of both electron-donors and acceptors exhibit better device performance as a result of balanced carrier injection. [9] Therefore, in order to improve device efficiency and balance electron and hole injection, the architectures of EL polymers which possess both holetransporting and electron-transporting segments have been widely adapted. [10][11][12][13] For instance, in our previous studies on poly(aryl ether)s consisting of alternate isolated holetransporting and electron-transporting/emissive fluorophores we confirmed that both electron and hole affinities are enhanced simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Connector Effect in Electroluminescent Properties of Poly(p‐phenylene vinylene) Derivatives Containing Triazole Chromophores

Chen

2006

Macro Chemistry & Physics

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Summary: We report the thermal, optical, electrochemical and electroluminescent properties of four polymers P1–P4 consisting of hole‐transporting [1,4‐bis(hexyloxy)‐2,5‐distyrylbenzene;DSB] and electron‐transporting [4‐(4‐(hexyloxy)phenyl)‐3,5‐diphenyl‐4H‐1,2,4‐triazole; TAZ] fluorophores linked by four kinds of connectors: (1) ether spacers, (2) single bonds, (3) 1,4‐phenylenes, and (4) 1,4‐divinylbenzenes. These polymers are soluble in common organic solvents such as chloroform, N‐methylpyrrolidone (NMP) and CH2Cl2CH2Cl2 and exhibit good thermal stability with decomposition temperatures higher than 340 °C. Compounds M1–M3 containing a TAZ or DSB core were employed as a model to study the optical properties of the polymers. The photoluminescence (PL) spectral maxima of P1–P4 in CHCl3 were spread over a wide range, from 453 nm to 501 nm, depending upon the chemical structures of the connectors. In the film state, the PL maxima shifted bathochromically from 464nm to 538 nm, which can be attributed to the formation of excimers. From the optimized semiempirical modified neglect of diatomic overlap (MNDO) calculations, the adjacent benzene rings between DSB and TAZ chromophores in P2 and P3 twist about 81–89° which is significantly different from P4 (circa 0°). The effect of the twisted connector architectures on optical and electrochemical properties for P1–P4 is discussed. The electroluminescences of P1–P4 and corresponding Commission Internationale de l'Eclairage (C.I.E.) coordinates are also depicted to indicate that incorporating different connectors to these polymers changed their color from blue, to green, to the yellow region.The C.I.E. 1931 diagram of lights emitted from the PLED devices (ITO/PEDOT:PSS/P1–P4/Al).magnified imageThe C.I.E. 1931 diagram of lights emitted from the PLED devices (ITO/PEDOT:PSS/P1–P4/Al).

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“…(Gondek, et al, 2008;Patra, et al, 2002;Yu, et al, 1995;Shaheen, et al, 2001;Tessler, Denton & Friend, 1996;Samuel & Turnbull, 2007). Typically, these dyes have a donor-acceptor structure that controls their photophysical properties (Patra, et al, 2002;Zhou, et al, 2008;Adès, et al, 2000). Aromatic amines are among the most important derivatives as materials for hole transport in nanodevices (Pai, Yanus & Stolka, 1984;Naito & Miura, 1993;Okutsu, et al, 1997;Thelakkat, et al, 1999;Yakushchenko, et al, 1999;Strzelec, et al, 2001;Jiang, et al, 2002;Loy, Koene & Thompson, 2002;Xin, et al, 2002;Chen, et al, 2003;Satoh, et al, 2003;Salbeck, 1996;Strohriegl & Grazulevicius, 2002), and have been used in a wide range of structures, either as separate layers (Salbeck, 1996;Friend, 1999) or covalently attached to light emitting layers (Loy, Koene & Thompson, 2002;Redecker, et al, 1999;Miteva, et al, 2001;Ego.…”

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confidence: 99%

“…Some dyes with donor-acceptor structures have been formed in a Heck coupling reaction with palladium-catalysis (Patra, et al, 2002), while others have been formed in the Knoevenagel condensation (Knoevenagel, 1896). Our group previously has synthesized different conjugated compounds with the Knoevenagel condensation, without any catalyst and under solvent-free conditions (Percino, et al, 2007(Percino, et al, , 2008(Percino, et al, , 2006(Percino, et al, , 2010.…”

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confidence: 99%

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Synthesis and Characterization of Conjugated Pyridine-(N-diphenylamino) Acrylonitrile Derivatives: Photophysical Properties

Percino¹,

Chapela²,

Cerón³

et al. 2012

JMSR

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We have synthesized four novel highly conjugated and fluorescent compounds, 2-(phenyl)-3-(4-diphenylaminophenyl) acrylonitrile (I), 2-(2´-pyridyl)-3-(4-diphenylamino-phenyl) acrylonitrile (II), 2-(3´-pyridyl)-3-(4-diphenylaminophenyl) acrylonitrile III) and 2-(4´-pyridyl)-3-(4-diphenylaminophenyl) acrylonitrile (IV) by the Knoevenagel condensation. In solution, the UV-vis spectra showed two maxima for each compound, one at ~296-300 nm and the other at ~403-428 nm. The compounds showed fluorescence emission in CHCl 3 solution as well as in the state solid. The fluorescence quantum yield for the compounds in powder form showed values ranging from 0.07-0.11. Structures were confirmed with IR, MS, and NMR spectroscopy. Molar coefficient absorption, absorbance, fluorescence emission spectra and fluorescence quantum yield ( f ) were compared to evaluate the effects of the diphenylamino-substituents and the position of nitrogen on the electronic properties of phenylpyridylacrylonitriles compounds.

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Electroluminescence Properties of Systematically Derivatized Organic Chromophores Containing Electron Donor and Acceptor Groups

Cited by 49 publications

References 23 publications

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Starburst DCM-Type Red-Light-Emitting Materials for Electroluminescence Applications

Connector Effect in Electroluminescent Properties of Poly(p‐phenylene vinylene) Derivatives Containing Triazole Chromophores

Synthesis and Characterization of Conjugated Pyridine-(N-diphenylamino) Acrylonitrile Derivatives: Photophysical Properties

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