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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Journal ArticleDOI
Synthesis and Electrochemical Properties of Peripheral Carbazole Functional Ter(9,9-spirobifluorene)s
Shi Tang,Meirong Liu,Cheng Gu,Yang Zhao,Ping Lu,Dan Lu,Linlin Liu,Fangzhong Shen,Bing Yang,Yuguang Ma +9 more
TL;DR: The oxidation potentials of spirobifluorene trimers S TCPC-6 and STCPC-4 were significantly lower than that of model compound STHPH without peripheral carbazole groups, which reflect that the title compounds process higher HOMO energy level and better hole-injection ability.
Journal ArticleDOI
Light-Induced Solubility Modulation of Polyfluorene To Enhance the Performance of OLEDs.
Korwin M. Schelkle,Markus Bender,Krischan Fabian Jeltsch,Tiago Buckup,Klaus Müllen,Manuel Hamburger,Uwe H. F. Bunz +6 more
TL;DR: Light-induced modulation of the solubility of π-conjugated polymers (polyfluorene) with side chains functionalized with hydroxycinnamic acid is reported, offering the possibility for further development in terms of manipulating thesolubility and emissive parameters of an important class of functional materials.
Journal ArticleDOI
High-performance polymer-based electrophosphorescent light-emitting diodes
TL;DR: In this article, high-performance electrophosphorescent light-emitting diodes (LEDs) were demonstrated with tris-[9,9-dihexyl-2-(pyridinyl-2′) fluorene] iridium(III) [Ir(DPF)3], tris-{9, 9,dihexylon-2-[phenyl-4′-(-pyrin-2″-yl)] fluorenea} iridium[Ir(III)] iridium, and tris]-2,5-
Journal ArticleDOI
Synthesis, characterization and optical properties of oligoketanils containing carbon–carbon double bond in the main chain
Agnieszka Iwan,Danuta Sek,Patrice Rannou,Janusz Kasperczyk,Henryk Janeczek,Zbigniew Mazurak,Adam Pron +6 more
TL;DR: Protonation with DEHEPSA transforms blue radiation emitters into the green radiation ones, which results in a large decrease of the glass transition temperatures (Tg), from values exceeding 373 K to values close to room temperature, improving by consequence their flexibility as discussed by the authors.
Journal ArticleDOI
A thermally stable anthracene derivative for application in organic thin film transistors
TL;DR: In this paper, a novel multifunctional anthracene derivative 2,6-bis(dibenzo[b,d]furan-3-yl)anthracene (BDBFAnt) was designed and synthesized for application in OTFT devices, which is highly innovative due to their suitable carrier transport ability, excellent thermal stability, fine film-forming property, rigid planarity and outstanding fluorescence.
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