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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Star-shaped π-conjugated oligomers and their applications in organic electronics and photonics
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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.
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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.
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Efficient blue-emitting silafluorene–fluorene-conjugated copolymers: selective turn-off/turn-on detection of explosives
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References
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The built-in potential in blue polyfluorene-based light-emitting diodes
Vladimir Bodrozic,Vladimir Bodrozic,Thomas M. Brown,Shabbir M. Mian,Daren J. Caruana,Daren J. Caruana,Matthew Roberts,Nathan Phillips,Jonathan Halls,Ilaria Grizzi,Jeremy Burroughes,Franco Cacialli,Franco Cacialli +12 more
TL;DR: In this paper, energy level alignment in polyfluorene-based polymer light-emitting diodes (PLEDs) is studied with electroabsorption spectroscopy and cyclic voltammetry (CV).
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A new organic/inorganic electroluminescent material with a silsesquioxane core
Chih-Chia Cheng,Chen Han Chien,Ying-Chieh Yen,Yun-Sheng Ye,Fu-Hsiang Ko,Chun-Hung Lin,Feng-Chih Chang +6 more
TL;DR: In this paper, a new polyhedral oligomeric silsesquioxane (POSS)-based blue-light electroluminescent nanoparticle, octakis[ N -(9-ethyl-9 H -carbazol-3-yl)undecanamide-11-dimethylsiloxy]silsesquioxanes (C11-Cz), was described.
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Keto defect sites in fluorene-based organic field-effect transistors: The origin of rapid degradation on the performance of the device
Yong-Young Noh,Dong-Yu Kim,Yuji Yoshida,Kiyoshi Yase,Byung Jun Jung,Eunhee Lim,Hong-Ku Shim,Reiko Azumi +7 more
TL;DR: In this article, the effect of keto defects in fluorene units on the performance of organic field effect transistors (OFETs) was examined based on BFTT and biphenyl end-capped fused bithiophenes (BPTT) oligomers.
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Fluorescence Emission Anisotropy Coupled to an Electrochemical System: Study of Exciton Dynamics in Conjugated Polymers
TL;DR: In this paper, anisotropy studies have been performed for two types of conjugated polymers: phenylene−vinylene (MDMO−PPV) and fluorene−phenylene (PFP) based polymers.
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Polymer/nanoporous silica nanocomposite blue-light-emitting diodes
TL;DR: In this article, a blue-light-emitting polymer/mesoporous silica nanocomposite was prepared by blending poly(9,9-dioctylfluorene) with nanosized MCM-41.