Open Access
Stabilized Blue Emission from Polyfluorene-Based Light-Emitting Diodes: Elimination of Fluorenone Defects
Xiong Gong
- Vol. 13
TLDR
In this paper, the photoluminescence (PL) and electroluminescent (EL) of polyfluorene (PF)-based light-emitting diodes (LEDs) were studied and it was shown that the low-energy emission band originates from fluorenone defects which are introduced by photo-oxidization, thermal oxidation, or during device fabrication.Abstract:
Polyfluorene (PF)-based light-emitting diodes (LEDs) typically exhibit device degradation under operation with the emergence of a strong low-energy emission band (at ∼ 2.2–2.4 eV). This longer wavelength band converts the desired blue emission to blue–green or even yellow. We have studied both the photoluminescence (PL) and electroluminescence (EL) of PFs with different molecular structures and found that the low-energy emission band originates from fluorenone defects which are introduced by photo-oxidization, thermal oxidation, or during device fabrication. X-ray photo-emission spectroscopy (XPS) results show that the oxidation of PF is strongly catalyzed by the presence of calcium. The fluorenone defects generate a stronger contribution to the EL than to the PL. By utilization of a novel electron-transporting material as a buffer layer between the emissive PF and the Ca/Ag (Ba/Ag) cathode, the blue EL emission from the PF was stabilized.read more
Citations
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Synthesis of novel conjugated polymer based on cyclopenta[def]phenanthrene and vinylene with strong interchain interaction
Youngeup Jin,Minjung Lee,Sun Hee Kim,Suhee Song,I. L. Kim,Han Young Woo,Kwanghee Lee,Hongsuk Suh +7 more
TL;DR: In this paper, a novel conjugated polymer, poly(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene-2,6-vinylene) (PCPPV) has been synthesized and characterized.
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Synthesis and photo- and electrophysical properties of conjugated copolyfluorenes with 7,8,10-triarylfluoranthene fragments in the main chain
Mukhamed L. Keshtov,Eugene I. Mal’tsev,S. I. Pozin,D. V. Marochkin,Valery P. Perevalov,Inesa V. Blagodatskikh,Pavel V. Petrovskii,Alexei R. Khokhlov +7 more
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Probing Metal/Organic Interfaces Using Doubly-Resonant Sum Frequency Generation Vibrational Spectroscopy
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New photo- and electroluminescent conjugated copolyfluorenes with 7,8,10-triarylfluoranthene units in the backbone
TL;DR: The dibromo derivative of fluoranthene 1-[7,10-bis(4-bromophenyl)fluoranthen-8-yl]pyrene was synthesized and used to prepare three new copolyfluorenes containing 3, 5, and 10 mol % 7,8, 10-triarylfluoranthene groups via the Yamamoto reaction as mentioned in this paper.
References
More filters
Journal ArticleDOI
Multilayer polymer light-emitting diodes : White-light emission with high efficiency
Journal ArticleDOI
Star-shaped π-conjugated oligomers and their applications in organic electronics and photonics
TL;DR: These structures are monodisperse, well-defined, discrete molecules with 100% synthetic reproducibility, and possess high purity and excellent solubility in common organic solvents and are therefore extremely attractive alternatives to conjugated polymers.
Journal ArticleDOI
Suzuki Polycondensation: Polyarylenes à la Carte
TL;DR: This review draws a rather comprehensive picture of how Suzuki polycondensation was discovered in 1989 and how it was subsequently developed into the most powerful polymerization method for polyarylenes during the last 20 years.
Journal ArticleDOI
Blue-light-emitting oligoquinolines: Synthesis, properties, and high-efficiency blue-light-emitting diodes
Christopher J. Tonzola,Abhishek P. Kulkarni,Angela P. Gifford,Werner Kaminsky,Samson A. Jenekhe +4 more
TL;DR: In this article, the synthesis, photophysics, cyclic voltammetry, and highly efficient blue electroluminescence of a series of n-type conjugated oligomers are reported.
Journal ArticleDOI
Efficient blue-emitting silafluorene–fluorene-conjugated copolymers: selective turn-off/turn-on detection of explosives
TL;DR: In this article, the synthesis and spectroscopic characterization of a series of new blue-emitting silafluorene-fluorene copolymers is described, which are synthesized using kinetically controlled hydrosilylation copolymerization of 1,1-dihydridosilafluoresne with a series 9-substituted 2,7-diethynylfluorenes.